update dependencies to current releases (closes #19 )

Direct deps bumped to their latest release: age v1.2.1 to v1.3.2, cobra v1.9.1 to v1.10.2, testify v1.8.4 to v1.12.1, x/crypto v0.38.0 to v0.57.0, x/term v0.32.0 to v0.46.0, btcutil v1.1.6 to v1.2.0, btcd v0.24.2 to v0.25.0. go-bip39 is already at v1.1.0 and the secret module at its latest commit. btcd is held at v0.25.0: v0.26.x moved the chaincfg and wire packages into separate /v2 modules, a breaking migration our chaincfg import and the pinned secret dependency's v1 btcutil cannot take without upstream work. go mod tidy normalized the go directive to 1.26.0. No test vector changed. Model: opus-4-8
2026-09-21 07:25:57 +00:00
43 changed files with 349 additions and 2060 deletions
@@ -1,68 +1,3 @@
-# .dockerignore does NOT use .gitignore semantics. Docker matches with
+.git
 # moby/patternmatcher: filepath.Match plus `**`, so `*` does not cross
 # `/` and an unprefixed pattern is anchored at the context root. Every
 # depth-independent pattern therefore needs `**/`, or `config/.env` and
 # `certs/server.key` still ship while this file reads as solved. Only
 # genuinely root-anchored entries go unprefixed. Never transplant these
 # into .gitignore, where `**/` is wrong.
 #
 # Matching is case-sensitive, so secrets use character ranges rather
 # than an ALL-CAPS twin, which would still miss `Server.Key`.
 #
 # Extend with this repo's own host-built artifacts, written anchored:
 # `/myapp`, never `**/myapp`, which also matches `cmd/myapp/` and
 # deletes the package directory from the context.
 # .git is sent without its config. Without a VERSION build argument the
 # stage that compiles runs `git describe --tags --always` on .git, which
 # does not need .git/config; that file can hold a credential, such as a
 # password in a remote URL or the token the CI checkout step stores there.
 # Each submodule keeps a config with the same exposure in its git directory
 # under .git/modules/, nested again for a submodule's own submodules.
 .git/config
 .git/modules/**/config
 # Agent scratch: one full checkout of the repo per in-flight agent.
 # Anchored because it occurs once where agents run at the repo root.
 # KNOWN GAP: a repo running agents in subdirectories still ships
 # `services/api/.claude/` and must add its own anchored entry.
 .claude
 # Environment files. `*.env` covers bare `.env` and the `prod.env`
 # convention. Re-include a committed template with a negation if the
 # build needs one: `!docs/example.env`.
 **/*.[eE][nN][vV]
 **/.[eE][nN][vV].*
 **/.[eE][nN][vV][rR][cC]
 # Private keys and the bundles carrying them. Public certificates
 # (*.crt, *.cer) are deliberately absent: they are legitimate inputs.
 **/*.[pP][eE][mM]
 **/*.[kK][eE][yY]
 **/*.[pP]12
 **/*.[pP][fF][xX]
 **/[iI][dD]_[rR][sS][aA]
 **/[iI][dD]_[dD][sS][aA]
 **/[iI][dD]_[eE][cC][dD][sS][aA]
 **/[iI][dD]_[eE][dD]25519
 # Dependencies: restored inside the image, never copied in.
 **/node_modules
 # OS metadata.
 **/.DS_Store
 **/Thumbs.db
 # Editor state: never a build input, and it churns COPY.
 **/*.swp
 **/*.swo
 **/*~
 **/*.bak
 **/.idea
 **/.vscode
 **/*.sublime-*
 # The binary `make build` writes, and the CI workflow, which is not a
 # build input.
 /keyfunc
 .gitea
 /keyfunc
@@ -6,7 +6,4 @@ jobs:
        steps:
            # actions/checkout v4.2.2, 2026-02-22
            - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
              with:
                  # All history and tags, which `git describe --tags` needs.
                  fetch-depth: 0
            - run: script/cibuild
@@ -1,3 +1,6 @@
 # The built binary
 /keyfunc
 # OS
 .DS_Store
 Thumbs.db
@@ -11,38 +14,8 @@ Thumbs.db
 .vscode/
 *.sublime-*
-# Agent scratch (worktrees of this repo, created and destroyed by
+# Environment / secrets
-# in-flight tooling). Unanchored: .gitignore patterns already match at
+.env
-# every depth, so no prefix is wanted here. This is not a .dockerignore
+.env.*
-# entry and must not be given a `**/` prefix on the way into one.
+*.pem
-.claude/
+*.key
 # Node
 node_modules/
 # Secrets. Unanchored like every entry above, so each matches at every
 # depth. Matching is case-sensitive on Linux, so names use character
 # ranges rather than a lowercase form that misses `Server.Key`.
 # Environment files. `*.env` covers bare `.env` and the `prod.env`
 # convention. Only the templates `example.env` and `sample.env` are
 # re-included below. A repository that commits any other template adds
 # its own negation after these lines, for example `!.env.example`.
 *.[eE][nN][vV]
 .[eE][nN][vV].*
 .[eE][nN][vV][rR][cC]
 !example.env
 !sample.env
 # Private keys and the bundles carrying them.
 *.[pP][eE][mM]
 *.[kK][eE][yY]
 *.[pP]12
 *.[pP][fF][xX]
 [iI][dD]_[rR][sS][aA]
 [iI][dD]_[dD][sS][aA]
 [iI][dD]_[eE][cC][dD][sS][aA]
 [iI][dD]_[eE][dD]25519
 # The binary `make build` writes.
 /keyfunc
@@ -10,21 +10,14 @@ run:
 linters:
  default: all
  enable:
    # Successor to the deprecated gomodguard. Named explicitly, rather than
    # left to `default: all`, because it carries the module policy below.
    - gomodguard_v2
  disable:
    # Genuinely incompatible with project patterns
    - exhaustruct      # Requires all struct fields
-    - exhaustruct_v5   # Requires all struct fields (successor to exhaustruct)
+    - depguard         # Dependency allow/block lists
    - godot            # Requires comments to end with periods
    - wsl              # Deprecated, replaced by wsl_v5
    - wrapcheck        # Too verbose for internal packages
    - varnamelen       # Short names like db, id are idiomatic Go
    # Deprecated: the warning is attached to the old name, so it is
    # silenced by disabling that name, not by enabling the successor.
    - wsl              # Deprecated, replaced by wsl_v5
    - gomodguard       # Deprecated, replaced by gomodguard_v2
  settings:
    lll:
      line-length: 88
@@ -35,64 +28,6 @@ linters:
      max-complexity: 15
    dupl:
      threshold: 100
    depguard:
      # Test-support code must not be compiled into the shipped binary. A
      # test-support package exists to hand a test privileges the program
      # itself must never have, so a file that is not a test must not import
      # one. Test files, and the files inside a package whose directory name
      # ends in `test`, are where that code belongs, and are exempt.
      #
      # The deny list below is the one part of this file a repository is
      # expected to extend, and the only part it may. depguard matches an
      # import path against a list of prefixes, so it cannot be told "any path
      # whose last segment ends in test"; a repository's own test-support
      # packages have to be named here one at a time, by full import path,
      # under a module path that differs from repository to repository. Add
      # them; change nothing else.
      rules:
        test-support:
          list-mode: lax
          files:
            - "$all"
            - "!$test"
            - "!**/*test/**"
          deny:
            - pkg: net/http/httptest
              desc: >-
                Test-support code belongs in test files and in packages whose
                directory name ends in test, not in the shipped binary.
    # Only decisions already recorded in the Go package defaults are
    # listed here. Every entry matches the module path exactly.
    gomodguard_v2:
      blocked:
        - module: github.com/rs/zerolog
          recommendations:
            - log/slog
          reason: "Structured logging is stdlib log/slog."
        # One entry per pre-fork module path, because the later releases
        # are separate paths. A prefix match would be shorter but would
        # also reach github.com/go-redis/redismock, the test double for
        # the successor these entries recommend.
        - module: github.com/go-redis/redis
          recommendations:
            - github.com/redis/go-redis/v9
          reason: "Pre-fork module; use the maintained go-redis v9."
        - module: github.com/go-redis/redis/v7
          recommendations:
            - github.com/redis/go-redis/v9
          reason: "Pre-fork module; use the maintained go-redis v9."
        - module: github.com/go-redis/redis/v8
          recommendations:
            - github.com/redis/go-redis/v9
          reason: "Pre-fork module; use the maintained go-redis v9."
        - module: github.com/sergi/go-diff
          recommendations:
            - github.com/aymanbagabas/go-udiff
          reason: "No unified diff output; use go-udiff."
        - module: github.com/hexops/gotextdiff
          recommendations:
            - github.com/aymanbagabas/go-udiff
          reason: "Unmaintained fork; use go-udiff."
 issues:
  max-issues-per-linter: 0
@@ -1,4 +0,0 @@
 {
    "tabWidth": 4,
    "proseWrap": "always"
 }
@@ -1,11 +1,11 @@
-# The lint phase, the test phase and a development environment.
+# The formatting check, the tests and the build. Linting is not here:
-# script/lint and script/test each build one phase alone; a plain
+# it runs in its own pinned image, see Dockerfile.lint and script/lint,
-# `docker build .` builds both, because the last stage copies a file from
+# which script/cibuild runs before this file.
 # each. Formatting is checked on the host by script/fmt-check, not here.
-# Lint phase
+# golang:1.26-alpine, 2026-09-07
-# golangci/golangci-lint:v2.14.0, 2026-10-04
+FROM golang@sha256:ce864e7223ac17b1775e6fd0b4c0db580c2eb50e7953a427916379e4b92a1628 AS builder
-FROM golangci/golangci-lint@sha256:ad862ba6b3798cbe0fd9fd7408d498fd74fbd2623a92406b2fd3898faf0bf98f AS lint
+
 RUN apk add --no-cache make git
 WORKDIR /src
@@ -14,59 +14,13 @@ RUN go mod download
 COPY . .
-RUN golangci-lint run --config .golangci.yml ./...
+RUN make fmt-check
 RUN make test
 RUN make build
-# Test phase. -race needs cgo and so a C compiler, which the Debian Go
+# alpine:3.23, 2026-09-07
-# image ships.
+FROM alpine@sha256:fd791d74b68913cbb027c6546007b3f0d3bc45125f797758156952bc2d6daf40
 # golang:1.26.8-trixie, 2026-10-04. It carries Go 1.26.8, the version
 # script/bootstrap installs on the host; change both together, and the
 # same image in the last stage.
 FROM golang@sha256:eae2aaa6add2936cbf350dd0d2628b363461542f0c4b3c0b558957e0f2997379 AS test
-WORKDIR /src
+COPY --from=builder /src/keyfunc /usr/local/bin/keyfunc
-COPY go.mod go.sum ./
+ENTRYPOINT ["keyfunc"]
 RUN go mod download
 COPY . .
 RUN go test -timeout 90s -race -cover ./... || \
    { echo "--- Rerunning with -v for details ---"; \
      go test -timeout 90s -race -v ./...; exit 1; }
 # Development environment, and the last stage: a plain `docker build .`
 # builds this one. It holds the source tree in /src, what
 # script/bootstrap installs, and keyfunc built from that tree on the
 # PATH. Nothing is wanted from either phase above; the copies are what
 # make BuildKit build them first, so this stage cannot run unless lint
 # and test passed.
 # golang:1.26.8-trixie, 2026-10-04
 FROM golang@sha256:eae2aaa6add2936cbf350dd0d2628b363461542f0c4b3c0b558957e0f2997379
 COPY --from=lint /src/go.sum /dev/null
 COPY --from=test /src/go.sum /dev/null
 # A tar-stream context keeps the sender's file owners, which git refuses.
 RUN git config --system --add safe.directory /src
 WORKDIR /src
 # script/bootstrap needs only script/ and the dependency manifests.
 COPY script/ script/
 COPY go.mod go.sum package.json yarn.lock ./
 RUN script/bootstrap
 COPY . .
 # The version stamped into the binary: the VERSION build argument when one
 # is given, otherwise `git describe --tags --always` of the .git in the
 # build context. A context that carries .git and still yields no version
 # fails the build; with neither, as from a source tarball, it is "dev".
 ARG VERSION
 RUN version="${VERSION:-$(git describe --tags --always || echo dev)}"; \
    if [ -e .git ] && { [ -z "$version" ] || [ "$version" = dev ] || \
        [ "$version" = unknown ]; }; then \
        echo "no version could be derived although the build context carries .git" >&2; \
        exit 1; \
    fi; \
    make build VERSION="$version" && mv keyfunc /usr/local/bin/keyfunc
@@ -0,0 +1,15 @@
 # The linter, pinned by hash, with this repository linted inside it.
 # Building this file is how linting happens; see script/lint. Nothing
 # lints on the host, so the answer is the same everywhere.
 # golangci/golangci-lint:v2.12.2, 2026-09-07
 FROM golangci/golangci-lint:v2.12.2@sha256:5cceeef04e53efe1470638d4b4b4f5ceefd574955ab3941b2d9a68a8c9ad5240
 WORKDIR /src
 COPY go.mod go.sum ./
 RUN go mod download
 COPY . .
 RUN golangci-lint run --timeout 5m
@@ -1,21 +0,0 @@
 MIT License
 Copyright (c) 2026 sneak
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:
 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
@@ -3,10 +3,7 @@
 # which needs the version stamped into the binary.
 VERSION := $(shell git describe --tags --always --dirty 2>/dev/null || echo dev)
-LDFLAGS := -s -w -X 'sneak.berlin/go/keyfunc/internal/cli.Version=$(VERSION)'
+LDFLAGS := -s -w -X 'git.eeqj.de/sneak/keyfunc/internal/cli.Version=$(VERSION)'
 # Where script/bootstrap installs Go; it cannot put it on our PATH.
 export PATH := $(HOME)/.local/go/bin:$(PATH)
 .PHONY: default bootstrap setup build test lint fmt fmt-check check \
 	docker cibuild hooks clean
@@ -1,79 +1,16 @@
 # keyfunc
-`keyfunc` is an MIT-licensed Go command-line tool by
+`keyfunc` turns a BIP-39 mnemonic into key pairs that can be recreated from
-[@sneak](https://sneak.berlin) that turns a BIP-39 mnemonic into SSH keys, age
+that mnemonic at any time. The same mnemonic, key type and index always give the
-identities and child mnemonics, each of which can be recreated from that
+same key.
 mnemonic at any time. The same mnemonic, key type and index always give the same
 key.
 It uses the BIP-85 entropy deriver from `git.eeqj.de/sneak/secret/pkg/bip85` and
 takes the same steps as that repository's `agehd` package.
-Commands are grouped by what is derived: `keyfunc ssh ...` for ed25519 SSH keys,
+Commands are grouped by what is derived: `keyfunc ssh ...` for ed25519 SSH
-`keyfunc age ...` for age identities and for encrypting and decrypting with
+keys, `keyfunc age ...` for age identities and for encrypting and decrypting
-them, and `keyfunc mnemonic ...` for child mnemonics derived from the main one.
+with them, and `keyfunc mnemonic ...` for child mnemonics derived from the
-
+main one.
 ## Getting Started
 Install with Go:
 ```
 go install sneak.berlin/go/keyfunc/cmd/keyfunc@latest
 ```
 Or build from a clone and run the binary:
 ```
 git clone git@git.eeqj.de:sneak/keyfunc.git
 cd keyfunc
 make build
 ./keyfunc --version
 ```
 `make build` produces `./keyfunc`. Every deriving command needs a mnemonic; see
 [Giving it the mnemonic](#giving-it-the-mnemonic) for where it is read from,
 then for example:
 ```
 ./keyfunc ssh pub -n 0 --mnemonic-command 'secret get foo'
 ```
 ## Rationale
 A key you can derive again never has to be backed up. One mnemonic, kept safe
 once, stands behind every key this tool produces: lose a laptop and the SSH key,
 the age identity and any child mnemonic on it come back from the mnemonic alone,
 at the same index, byte for byte. Nothing else has to be written down, copied
 between machines, or stored in a secret manager, because it can always be
 derived again.
 ## Design
 The entry point is a thin `cmd/keyfunc/main.go` (what `make build` builds) that
 calls into `internal/`. The packages there are:
 - `internal/derive` turns a mnemonic into the 32 bytes a key is made from: it
  walks BIP-39 seed, BIP-32 master key and BIP-85 entropy, and holds the shared
  constants (the byte count and the largest key index).
 - `internal/mnemonic` finds the mnemonic to work from — a command, an
  environment variable, or a terminal prompt — and refuses one that fails the
  BIP-39 checksum.
 - `internal/sshkey` turns the derived bytes into an ed25519 SSH key
  (`sshkey.go`) and serves that key from an in-process SSH agent on a private
  unix socket, keeping it out of any file (`agent.go`).
 - `internal/agekey` turns the derived bytes into an age identity and encrypts
  and decrypts with it.
 - `internal/childmnemonic` derives a child mnemonic from the main one using
  BIP-85's own mnemonic application.
 - `internal/cli` builds the cobra command tree and runs it. Under it,
  `cli/options` holds the flags every command shares, and `cli/ssh`, `cli/age`
  and `cli/mnemonic` are the command groups.
 ### Adding a key type
 Adding a key type is one package under `internal/` that turns the 32 derived
 bytes into that type's key, plus one cobra subcommand under `internal/cli/` that
 groups its commands.
 ## Derivation
@@ -105,32 +42,26 @@ The mnemonic itself is never a command-line argument. It is looked for in this
 order; the first one found wins:
 1. `--mnemonic-command <command>`: a shell command, run with `sh -c`, whose
-   standard output is the mnemonic. Example:
+   standard output is the mnemonic. Example: `--mnemonic-command 'secret get
-   `--mnemonic-command 'secret get foo'`. If the command exits with a non-zero
+   foo'`. Whitespace around the output is dropped. If the command exits with a
-   status, the tool prints its standard error and exits with status 1.
+   non-zero status, the tool prints its standard error and exits with status 1.
-2. Environment variable `KEYFUNC_MNEMONIC_COMMAND`: the same, as a shell command
+2. Environment variable `KEYFUNC_MNEMONIC_COMMAND`: the same, as a shell
-   held in the environment.
+   command held in the environment.
 3. Environment variable `KEYFUNC_MNEMONIC`: the mnemonic itself.
 4. A prompt on the terminal with echo turned off.
 If none of these is available and standard input is not a terminal, the tool
 refuses and exits with status 1. A mnemonic that fails the BIP-39 checksum is
-refused with a message saying so. Keys are derived from the mnemonic's words
+refused with a message saying so.
 joined by single spaces, whatever whitespace is around or between them, so one
 word per line, tabs or extra spaces give the same keys.
 `KEYFUNC_MNEMONIC` and `KEYFUNC_MNEMONIC_COMMAND` are removed from the
 environment before the system `ssh` (`keyfunc ssh to`) and `sftp`
 (`keyfunc ssh install`) are started, so the mnemonic is never handed on to them.
 Every command takes `--index` / `-n` and `--mnemonic-command`, and has `--help`.
-`keyfunc --version` prints the version. `make build` stamps it; a binary
+`keyfunc --version` prints the version set at build time.
 installed with `go install` reports the module version instead.
 ## SSH keys: `keyfunc ssh`
-Only ed25519 keys are produced. The application number is `838372`, so the path
+Only ed25519 keys are produced. The application number is `838372`, so the
-is `m/83696968'/838372'/<n>'`. The 32 bytes from step 4 are the ed25519 seed.
+path is `m/83696968'/838372'/<n>'`. The 32 bytes from step 4 are the ed25519
 seed.
 Test vector, mnemonic
 `abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about`:
@@ -160,29 +91,25 @@ same as for `pub`.
 ### `keyfunc ssh install <[user@]host> [-- sftp options...]`
 Adds the `pub` line to `~/.ssh/authorized_keys` on the host. No command is run
-on the host: the file is fetched, changed here, and written back with the system
+on the host: the file is fetched, changed here, and written back with the
-`sftp` client in batch mode.
+system `sftp` client in batch mode.
-The first connection lists `~/.ssh`, then `~/.ssh/.`, and then fetches
+The first connection fetches `~/.ssh/authorized_keys`. The file reads as empty
-`~/.ssh/authorized_keys`. The file reads as empty in two cases only: `sftp`
+only when `sftp` reported that file as not being there — the one line naming
-reported `~/.ssh` itself as not being there, or both listings came up and the
+that path. The same wording anywhere else in the session does not count: `ssh`
-file was not found. Any other outcome of that connection fails the run — a
+writes `No such file or directory` about an `-i` it cannot find, on a session
-`~/.ssh` that is there but cannot be read or entered, an `authorized_keys` that
+that then authenticates through the agent. When `sftp` failed for any other
-is there but cannot be read, or a connection that did not come up — and the tool
+reason — the file is there and cannot be read, the connection did not come up —
-prints what `sftp` said and exits with status 1 without writing anything, rather
+the tool prints what `sftp` said and exits with status 1 without writing
-than put a file back holding the new key alone. The listings are what tell a
+anything, rather than put a file back holding the new key alone. What `sftp`
-missing directory from one shut to the user, which `sftp` reports on a fetch the
+cannot tell apart is a missing file and one in a directory it cannot enter, so a
-same way: one that cannot be read fails the first listing, and one that can be
+`~/.ssh` whose mode shuts the user out reads as a host with no file; the second
-read but not entered fails the second, after which the tool says that `~/.ssh`
+connection sets that mode to `0700` and writes, as on a host that has none. If
-cannot be entered. The wording of a missing file elsewhere does not count
+an identical line is already in the file, the tool prints
-either, since `ssh` writes `No such file or directory` about an `-i` it cannot
+`already present` and connects no further. Otherwise the line is added (after a
-find on a session that then authenticates through the agent. If an identical
+newline, if the file did not end with one) and a second connection:
 line is already in the file, the tool prints `already present` and connects no
 further. Otherwise the line is added (after a newline, if the file did not end
 with one) and a second connection:
- makes `~/.ssh` and sets it to mode `0700`, but only when the first connection
+- creates `~/.ssh` and sets it to mode `0700`;
  found none; a `~/.ssh` that was already there keeps the mode it had;
 - uploads the new file as `~/.ssh/authorized_keys.keyfunc-<random>` and sets it
  to mode `0600`;
 - renames that file over `~/.ssh/authorized_keys`.
@@ -190,22 +117,20 @@ with one) and a second connection:
 The tool then prints `added`. So a run that adds a line connects twice. The
 rename is the step that either happens or does not: the file on the host is
 never half-written. `sftp` does it in one step against servers that offer
-OpenSSH's POSIX rename extension, as OpenSSH's own server does; a server without
+OpenSSH's POSIX rename extension, as OpenSSH's own server does; a server
-it may refuse to rename onto a file that is already there.
+without it may refuse to rename onto a file that is already there.
 If a step fails, the tool prints what `sftp` said, removes nothing, and exits
-with status 1. It names the uploaded file only when the step that failed was the
+with status 1. It names the uploaded file only when the step that failed was
-upload or one after it, which is where a file of that name can be on the host; a
+the upload or one after it, which is where a file of that name can be on the
-failure before the upload names none. Everything `sftp` writes goes to standard
+host; a failure before the upload names none. Everything `sftp`
-error, so the tool's own standard output is only `added` or `already present`.
+writes goes to standard error, so the tool's own standard output is only
 `added` or `already present`.
 Anything after `--` is passed to `sftp` unchanged, which is where the port goes
 (`-P 2222`, not `-p`). How the connection authenticates is up to the user's
 normal `ssh` setup, except that batch mode does not prompt: a key or an agent
-has to do it, not a typed password. Nor does it ask whether to trust a host key
+has to do it, not a typed password.
 it has not seen, so the host has to be in `known_hosts` already, or the run
 fails with `Host key verification failed`. Connect to the host once with `ssh`
 first, or pass `-o StrictHostKeyChecking=accept-new` after `--`.
 ### `keyfunc ssh to <host> [ssh arguments...]`
@@ -213,26 +138,15 @@ Derives the key, serves it from an SSH agent that runs inside the tool on a unix
 socket in a new private `0700` temporary directory, then runs the system `ssh`
 with `-o IdentityAgent=<that socket>` followed by the host and all remaining
 arguments unchanged. The tool exits with `ssh`'s exit status and removes the
-socket and directory on the way out. The private key is never written to disk. A
+socket and directory on the way out. The private key is never written to disk.
 SIGINT, SIGTERM or SIGHUP ends `ssh` and still removes the socket and directory,
 and the tool then exits with status 1 unless `ssh` reported one of its own.
 ## age identities: `keyfunc age`
 The application number is `657169`, path `m/83696968'/657169'/<n>'`. The 32
-bytes from step 4 are clamped as X25519 requires and become an age identity, the
+bytes from step 4 are clamped as X25519 requires and become an age identity,
-same steps `sneak/secret` takes in its `agehd` package. `secret` derives at a
+the same steps `sneak/secret` takes in its `agehd` package. `secret` derives at
-vendor-specific path today; for its keys to equal this tool's it moves to this
+a vendor-specific path today; for its keys to equal this tool's it moves to
-path, which is a change in `secret`, not here.
+this path, which is a change in `secret`, not here.
 Test vectors, mnemonic
 `abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about`:
 ```
 recipient index 0: age1xwdy9y6ckyfsgjc8k02e9uhsf3fmjy0ufysewlj68kmx5n67e3nsg2mftq
 recipient index 1: age1pmm92sxaf5mazjwvjph7dx2zq9r5p8l3rarfgqm7hmakqhvgyy4q5p3w7j
 identity index 0: AGE-SECRET-KEY-19QKK2P38598XLXMQFFU3P7J9PLDD7527T70JDHGDJ7AMNF3XT44S00JFU5
 ```
 ### `keyfunc age pub`
@@ -260,110 +174,39 @@ says so and exits with status 1.
 ### `keyfunc mnemonic [-n N] [--words 12|18|24]`
 Prints a child mnemonic derived from the main one, using BIP-85's own mnemonic
-application (number `39`, English, path `m/83696968'/39'/0'/<words>'/<n>'`,
+application (number `39`, English, path
-entropy taken as the specification says, not through step 4). Default 12 words.
+`m/83696968'/39'/0'/<words>'/<n>'`, entropy taken as the specification says,
-A child mnemonic is a full mnemonic in its own right: it can seed another
+not through step 4). Default 12 words. A child mnemonic is a full mnemonic in
-`keyfunc`, another wallet, or `secret`, and it never has to be written down,
+its own right: it can seed another `keyfunc`, another wallet, or `secret`, and
-since it can be derived again.
+it never has to be written down, since it can be derived again.
-Test vector, mnemonic
+## Adding a key type
 `abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about`:
-```
+Adding a key type is one package under `internal/` that turns the 32 derived
-index 0: prosper short ramp prepare exchange stove life snack client enough purpose fold
+bytes into that type's key, plus one cobra subcommand under `internal/cli/` that
-```
+groups its commands.
 The child-mnemonic step is also checked against BIP-85's own published vectors.
 Those start from the specification's master key
 `xprv9s21ZrQH143K2LBWUUQRFXhucrQqBpKdRRxNVq2zBqsx8HVqFk2uYo8kmbaLLHRdqtQpUm98uKfu3vca1LqdGhUtyoFnCNkfmXRyPXLjbKb`
 rather than from a mnemonic, so they cannot be given to `keyfunc`; at key index
 0 the 12-word English child mnemonic of that key is:
 ```
 girl mad pet galaxy egg matter matrix prison refuse sense ordinary nose
 ```
 ## Errors
-Errors go to standard error and the exit status is 1, except for `ssh to`, which
+Errors go to standard error and the exit status is 1, except for `ssh to`,
-passes through `ssh`'s own exit status.
+which passes through `ssh`'s own exit status.
-SIGINT, SIGTERM and SIGHUP end any command at once, at the mnemonic prompt too,
+## Building and running
 with the status a shell gives a program killed by that signal (130 for SIGINT).
 An interrupted `age encrypt -o` or `age decrypt -o` leaves no file. While it is
 writing the file, the signal makes it remove the unfinished file, leave a file
 already at the named path as it was, and exit with status 1. It puts the file in
 place a tenth of a second after its input ends, and a signal in that time still
 counts: Ctrl-C on a pipeline also ends the program feeding it, so the input can
 end just before the signal arrives. While `ssh to` or `ssh install` has `ssh` or
 `sftp` running, the signal ends that program instead, the tool removes its agent
 socket or working files, and it exits with status 1, or for `ssh to` with
 `ssh`'s own status if `ssh` reported one.
-## Entrypoints
+```
 make build    # produces ./keyfunc
 make check    # fmt-check, lint (golangci-lint) and tests
 ```
-The repo adheres to the
+Examples:
 [Scripts to Rule Them All](https://github.com/github/scripts-to-rule-them-all)
 standard: most Makefile targets are thin shims over an executable in `script/`
 (`build` and `clean` are the exceptions).
- `script/bootstrap` installs, idempotently, everything needed to build and
+```
-  develop apart from Docker, which it only warns about when it is missing, and
+keyfunc ssh pub -n 3 --mnemonic-command 'secret get foo'
-  the linter, which only runs inside Docker. In this order:
+keyfunc ssh priv -n 3 > ~/.ssh/id_bip85_3
-    - git and make from nix, apt, brew or apk, and from there too curl and bash
+keyfunc ssh install -n 3 user@example.com
-      when a later step needs them;
+keyfunc ssh to -n 3 user@example.com uptime
-    - Go at the version the `Dockerfile`'s Go image carries, from the official
+keyfunc age pub -n 0
-      release archive at go.dev (checked against a sha256 in the script) into
+keyfunc age encrypt -n 0 --armor -o notes.age notes.txt
-      `~/.local/go`, unless the `go` first on the `PATH` already is that
+keyfunc age decrypt -n 0 notes.age
-      version; then the Go modules. `script/bootstrap` itself, `script/fmt`,
+keyfunc mnemonic -n 1 --words 24
-      `script/fmt-check`, `script/precommit` and the `Makefile` put
+```
      `~/.local/go/bin` first on their `PATH`, so they use that Go;
    - node: an installed one is used as it is, otherwise a pinned one is
      installed through nvm, which, when it is missing, comes from its release
      archive, checked against a sha256;
    - yarn: an installed one is used as it is, otherwise the pinned version
      through corepack, or through npm where there is no corepack;
    - the pinned prettier, through yarn.
 - `script/setup` prepares a fresh clone: it runs `bootstrap`, then installs the
  git pre-commit hook.
 - `script/projectname` prints the project name; other scripts call it so they
  stay identical across repos.
 - `script/test` builds the `test` phase of the `Dockerfile` alone, uncached: the
  test suite runs with the race detector inside the build, rerunning verbosely
  if a test fails.
 - `script/lint` builds the `lint` phase of the `Dockerfile` alone, uncached: the
  linter, pinned by hash, runs inside the build, so a complaint fails it and
  leaves no container behind.
 - `script/fmt` formats in place: the Go source with `go fmt`, then every
  Markdown file with prettier (four-space indents, prose wrapped at 80 columns).
 - `script/fmt-check` checks the same files the same way without writing, failing
  if anything is unformatted. Both need the node, yarn and prettier that
  `bootstrap` installs.
 - `script/check` runs `test`, `lint` and `fmt-check` and changes no files.
 - `script/docker` builds the Docker image, uncached, tagged with the project
  name and stamped with the version `git describe` gives on the host. The image
  cannot be built unless the `lint` and `test` phases pass, so a plain
  `docker build .` runs them too. The image is a development environment, not a
  runtime image: the Debian Go image with what `script/bootstrap` installs, the
  source tree in `/src`, and `keyfunc` built from it on the `PATH`.
  `docker run --rm -it keyfunc` opens a shell in it.
 - `script/cibuild` is the CI build the Gitea workflow calls: it runs
  `bootstrap`, then `check`, then builds the image as `script/docker` does.
 - `script/precommit` is what the git pre-commit hook runs: `go mod tidy` and
  `go fmt`, failing if `go.mod` or `go.sum` changed, then `check`.
 - `script/install-precommit` installs the git pre-commit hook that runs
  `script/precommit`.
 ## TODO
 The open issues that stand between the tree and a 1.0 release:
 - [#42 go-bip39 no longer exists upstream: keep it, or copy it into the repo?](https://git.eeqj.de/sneak/keyfunc/issues/42)
 ## License
 MIT. The full text is in [`LICENSE`](LICENSE).
 ## Author
 [@sneak](https://sneak.berlin).
@@ -1,6 +1,6 @@
 ---
 title: Repository Policies
-last_modified: 2026-10-04
+last_modified: 2026-08-19
 ---
 This document covers repository structure, tooling, and workflow standards. Code
@@ -60,28 +60,17 @@ style conventions are in separate documents:
  prerequisite since nvm requires bash. yarn is then pinned via
  `corepack prepare yarn@<version> --activate`. Never install "latest" or "lts";
  always exact versions. `script/cibuild` runs the CI build: it changes to the
-  repo root, runs `script/bootstrap`, runs `script/check`, and builds the image
+  repo root and runs `docker build .`; the Gitea workflow calls it. Four further
-  with the version; the Gitea workflow calls it. **`script/cibuild` runs
+  scripts are our own extensions to the standard: `script/check` runs
-  `script/bootstrap` first**, because the workflow checks out the repo and runs
+  `script/test`, `script/lint`, and `script/fmt-check`; `script/precommit` is
-  nothing else, while `script/fmt-check` runs the formatter on the host: on a
+  what the git pre-commit hook runs, and it calls `script/check`;
-  pristine checkout with nothing installed the run dies there, after the
+  `script/install-precommit` installs the git pre-commit hook (the `make hooks`
-  containerised gates have passed. **The bootstrap alone is not enough**:
+  target shims to it); and `script/projectname` (literally that filename) simply
-  `script/bootstrap` installs node and yarn under nvm and leaves neither on the
+  outputs the project's name. Scripts that need the name call
-  `PATH` of the shell that called it, so a bare `yarn` still exits 127. The host
+  `script/projectname` — e.g. `script/docker` assembles its image tag from it —
-  entrypoints that need yarn — `script/fmt` and `script/fmt-check` — therefore
+  so those scripts stay byte-identical across all repos. Repo-type-specific
-  source nvm for the pinned node version before invoking it, exactly as
+  pre-commit extras (e.g. `go mod tidy` verification in Go repos) belong in
-  `script/bootstrap`'s own install step does. A runner carrying nothing but
+  `script/precommit`, not in the hook itself. Model scripts are at
  docker and git then gets through `script/check`. Four further scripts are our
  own extensions to the standard: `script/check` runs `script/test`,
  `script/lint` and `script/fmt-check`; `script/precommit` is what the git
  pre-commit hook runs, and it calls `script/check`; `script/install-precommit`
  installs the git pre-commit hook (the `make hooks` target shims to it); and
  `script/projectname` (literally that filename) simply outputs the project's
  name. Scripts that need the name call `script/projectname` — e.g.
  `script/docker` assembles its image tag from it — so those scripts stay
  byte-identical across all repos. Repo-type-specific pre-commit extras (e.g.
  `go mod tidy` verification in Go repos) belong in `script/precommit`, not in
  the hook itself. Model scripts are at
  `https://git.eeqj.de/sneak/prompts/raw/branch/main/script/<name>`. The README
  must document the provided scripts in an **Entrypoints** section (see the
  README requirements below).
@@ -100,171 +89,87 @@ style conventions are in separate documents:
  contributor should be able to understand the entire development workflow by
  reading the Makefile.
- Every repo should have a `Dockerfile`, and it carries the repo's gates: a
+- Every repo should have a `Dockerfile`. All Dockerfiles must run `make check`
-  `lint` phase and a `test` phase, with the final stage depending on both so the
+  as a build step so the build fails if the branch is not green. For non-server
-  image cannot be built unless they pass. For non-server repos the final stage
+  repos, the Dockerfile should bring up a development environment and run
-  brings up a development environment; for server repos it is the runtime image.
+  `make check`. For server repos, `make check` should run as an early build
-  Dockerfiles install development prerequisites by running `script/bootstrap`
+  stage before the final image is assembled. Dockerfiles install development
-  rather than duplicating installs inline; COPY `script/` and the dependency
+  prerequisites by running `script/bootstrap` rather than duplicating installs
-  manifests (`package.json` + `yarn.lock`, `go.mod` + `go.sum`, etc.) before
+  inline; COPY `script/` and the dependency manifests (`package.json` +
-  running it.
+  `yarn.lock`, `go.mod` + `go.sum`, etc.) before running it so the bootstrap
  layer stays cached until dependencies change.
- **Linting and testing run in Docker, as phases of the `Dockerfile`.** There is
+- **Dockerfiles must use a separate lint stage for fail-fast feedback.** Go
-  no separate lint file. `script/lint` and `script/test` each build one phase
+  repos use a multistage build where linting runs in an independent stage based
-  and nothing else:
+  on the `golangci/golangci-lint` image (pinned by hash). This stage runs
  `make fmt-check` and `make lint` before the full build begins. The build stage
  then declares an explicit dependency on the lint stage via
  `COPY --from=lint /src/go.sum /dev/null`, which forces BuildKit to complete
  linting before proceeding to compilation and tests. This ensures lint failures
  surface in seconds rather than minutes, without blocking on dependency
  download or compilation in the build stage.
-    ```sh
+    The standard pattern for a Go repo Dockerfile is:
    docker build --no-cache --target lint -t "$(script/projectname)-lint" .
    docker build --no-cache --target test -t "$(script/projectname)-test" .
    ```
    **A stage that is not the last one in the file is built only when the final
    stage's chain depends on it, or when `--target` names it.** That is why the
    two gates are always invoked by name here, and why the final stage carries a
    `COPY --from=` of a harmless file from each of them: without that edge a
    plain `docker build .` builds the last stage alone and exits 0 having linted
    and tested nothing.
    **Every `docker build` in `script/` is tagged**, here and in
    `script/cibuild` and `script/docker`. An untagged build leaves a dangling
    image behind on every invocation, on every developer host and every CI
    runner; a tagged one replaces the previous image.
    Inside a phase the tool is invoked directly — `golangci-lint`, `go test`,
    `eslint`, `prettier` — never through `make lint` or `script/test`, which are
    themselves a `docker build` and would recurse into a daemon that does not
    exist in a build step. Formatting is the exception and stays on the host:
    `script/fmt` writes the working tree, and `script/fmt-check` is its
    read-only twin.
    **No lint verdict may come from a host invocation of the linter.** On a
    shared host golangci-lint reads a result cache keyed on file content rather
    than location, so a second checkout of the same content is served the first
    one's findings, and a host-global lock in `$TMPDIR` makes concurrent runs
    exit non-zero with `parallel golangci-lint is running` — a status a caller
    cannot tell from real findings. Both have produced wrong verdicts in this
    org, in both directions. A container has its own cache, its own `TMPDIR` and
    a digest-pinned binary, so neither is reachable.
 - **Any build that runs checks is built with `--no-cache`.** Docker invalidates
  a `COPY` layer only when the copied content changes, so on an unchanged tree
  the check `RUN` is served from cache, nothing executes, and the build still
  exits 0. Every `docker build` in `script/` therefore passes `--no-cache`:
  `script/lint`, `script/test`, `script/cibuild` and `script/docker` are the
  four, and there is no fifth — `script/check` runs the two gate phases and
  `script/fmt-check`, and builds no image of its own. A bare `docker build .` is
  not evidence that anything ran: a sub-second build reporting success is a
  cache hit, not a result. Never invalidate by pruning — `docker builder prune`
  and friends destroy a build cache shared with every other build on the host.
 - **The gate phases are separate stages, and the build stage depends on both.**
  The lint phase is based on the `golangci/golangci-lint` image (pinned by
  hash), so lint failures surface in seconds rather than after a full compile,
  and the test phase is based on the Debian Go image. The canonical Go repo
  `Dockerfile`:
    ```dockerfile
-    # Lint phase
+    # Lint stage — fast feedback on formatting and lint issues
    # golangci/golangci-lint:v2.x.x, YYYY-MM-DD
    FROM golangci/golangci-lint@sha256:... AS lint
    WORKDIR /src
    COPY go.mod go.sum ./
    RUN go mod download
    COPY . .
-    RUN golangci-lint run --config .golangci.yml ./...
+    RUN make fmt-check
    RUN make lint
-    # Test phase. -race needs cgo and so a C compiler, which the Debian Go
+    # Build stage
    # image ships and the alpine one does not.
    # golang:1.x, YYYY-MM-DD
    FROM golang@sha256:... AS test
    WORKDIR /src
    COPY go.mod go.sum ./
    RUN go mod download
    COPY . .
    RUN go test -timeout 90s -race -cover ./... || \
        { echo "--- Rerunning with -v for details ---"; \
          go test -timeout 90s -race -v ./...; exit 1; }
    # Build stage. Nothing is wanted from either phase above; the copies
    # are what make BuildKit build them first, so this stage cannot run
    # unless lint and test passed.
    # golang:1.x-alpine, YYYY-MM-DD
    FROM golang@sha256:... AS builder
    COPY --from=lint /src/go.sum /dev/null
    COPY --from=test /src/go.sum /dev/null
    RUN apk add --no-cache git
    # A tar-stream context keeps the sender's file owners, which git refuses.
    RUN git config --system --add safe.directory /src
    WORKDIR /src
    # Force BuildKit to run the lint stage before proceeding
    COPY --from=lint /src/go.sum /dev/null
    COPY go.mod go.sum ./
    RUN go mod download
    COPY . .
    RUN make test
-    # The VERSION build arg when one is given, otherwise
+    ARG VERSION=dev
-    # `git describe --tags --always` on the .git in the build context. With
+    RUN CGO_ENABLED=0 go build -trimpath \
    # .git present, a version that is still empty, dev or unknown fails the
    # build: git is missing or could not read the checkout.
    ARG VERSION
    RUN VERSION="${VERSION:-$(git describe --tags --always)}"; \
        if [ -e .git ]; then \
            case "$VERSION" in ""|dev|unknown) \
                echo "version is '$VERSION' although .git is present" >&2; \
                exit 1 ;; \
            esac; \
        fi; \
        CGO_ENABLED=0 go build -trimpath \
        -ldflags="-s -w -X main.Version=${VERSION}" \
        -o /app ./cmd/app/
-    # Runtime stage, and the last one
+    # Runtime stage
    FROM alpine@sha256:...
    COPY --from=builder /app /usr/local/bin/app
    ENTRYPOINT ["app"]
    ```
    Key points:
-    - The lint phase uses the `golangci/golangci-lint` image directly (it has
+    - The lint stage uses the `golangci/golangci-lint` image directly (it
-      both Go and the linter), so nothing needs installing.
+      includes both Go and the linter), so there is no need to install the
-    - `COPY --from=<phase> /src/go.sum /dev/null` is a no-op copy whose only
+      linter separately.
-      purpose is the ordering edge. BuildKit runs stages in parallel by default,
+    - `COPY --from=lint /src/go.sum /dev/null` is a no-op file copy that creates
-      and a stage nothing depends on is not built at all, so without these two
+      a stage dependency. BuildKit runs stages in parallel by default; without
-      lines a red gate would not fail the build.
+      this line, the build stage would not wait for lint to finish and a lint
-    - Keep the runtime stage last, and if you add a stage after it, give it the
+      failure might not fail the overall build.
      same two copies. A plain `docker build .` builds the last stage's chain
      and nothing else.
    - If the project uses `//go:embed` directives that reference build artifacts
-      (e.g. a web frontend compiled in a separate stage), the lint phase must
+      (e.g. a web frontend compiled in a separate stage), the lint stage must
      create placeholder files so the embed directives resolve. Example:
      `RUN mkdir -p web/dist && touch web/dist/index.html web/dist/style.css`.
      The lint stage should not depend on the actual build output — it exists to
      fail fast.
    - If the project requires CGO or system libraries for linting (e.g.
-      `vips-dev`), install them in the lint phase with `apk add`.
+      `vips-dev`), install them in the lint stage with `apk add`.
-    - `.dockerignore` lets `.git` into the build context. It keeps out
+    - The build stage runs `make test` after compilation setup. Tests run in the
-      `.git/config` and each submodule's `config` under `.git/modules/` at any
+      build stage, not the lint stage, because they may require compiled
-      depth (`.git/modules/**/config`), which `git describe` does not need and
+      artifacts or heavier dependencies.
      which can hold a credential: a password in a remote URL, or the token the
      CI checkout step stores there. The stage that compiles has `git` (the
      Debian Go image has it; an alpine one needs `apk add --no-cache git`) and
      takes the version from the `VERSION` build argument when one is given,
      otherwise from `git describe --tags --always`. That gives the tag on a
      tagged commit; on a later commit, the tag, the number of commits since it
      and the short commit (`v1.2.3-4-gabc1234`); and the short commit when no
      tag is reachable. The stage that compiles also marks its working directory
      safe for git (`git config --system --add safe.directory /src`): a context
      sent as a tar stream keeps the sender's file owners, and git refuses a
      checkout owned by another user, so the version would come out empty.
      `ARG VERSION` has no default, and the build fails if the context carries
      `.git` and the version still comes out empty, `dev` or `unknown`. A plain
      `docker build .` with no build arguments must succeed; a Dockerfile that
      refuses an empty build argument drops that refusal and keeps the argument.
 - Every repo should have a Gitea Actions workflow (`.gitea/workflows/`) that
-  runs `script/cibuild` on push, and checks out the repo as its only other step.
+  runs `script/cibuild` (which runs `docker build .`) on push. Since the
-  That script bootstraps, runs the gate phases, and then builds the image, so a
+  Dockerfile already runs `make check`, a successful build implies all checks
-  successful run means every check passed; a bare `docker build .` does not
+  pass.
  carry the same guarantee, because its gate phases may come from the cache. The
  image build is uncached and so runs the gate phases a second time. That is the
  price of the rule above, and it is worth paying: the image that ships is built
  from a run of its own gates rather than from a cache entry.
 - Use platform-standard formatters: `black` for Python, `prettier` for
  JS/CSS/Markdown/HTML, `go fmt` for Go. Always use default configuration with
@@ -288,17 +193,15 @@ style conventions are in separate documents:
  suite that exceeds it fails. Under 20 seconds is the target. A suite between
  20 and 60 seconds is still green, but the overage must be filed as an
  improvement bug against that repo. Add a 90-second timeout to the test
-  invocation (`go test -timeout 90s`). The backstop deliberately sits above the
+  invocation in the Makefile (`go test -timeout 90s`). The backstop deliberately
-  hard cap so that it catches a genuinely hung test rather than a merely slow
+  sits above the hard cap so that it catches a genuinely hung test rather than a
-  one.
+  merely slow one.
- **The test command should use the conditional verbose rerun pattern.** Run
+- **`make test` should use the conditional verbose rerun pattern.** Run tests
-  tests without `-v` (verbose) first. If tests fail, automatically rerun with
+  without `-v` (verbose) first. If tests fail, automatically rerun with `-v` to
-  `-v` to show full output. This keeps CI logs and `docker build` output clean
+  show full output. This keeps CI logs and `docker build` output clean on
-  on success (just package/suite summaries) while providing full diagnostic
+  success (just package/suite summaries) while providing full diagnostic detail
-  detail on failure (every test case, every assertion). The command lives in the
+  on failure (every test case, every assertion). The general shell pattern:
  `test` phase of the `Dockerfile`, since `script/test` builds that phase; the
  Makefile form below is the same pattern for any repo-local invocation:
    ```makefile
    test:
@@ -311,26 +214,11 @@ style conventions are in separate documents:
    ```makefile
    test:
-    	@go test -count=1 -timeout 90s -race -cover ./... || \
+    	@go test -timeout 90s -race -cover ./... || \
    		{ echo "--- Rerunning with -v for details ---"; \
-    		  go test -count=1 -timeout 90s -race -v ./...; exit 1; }
+    		  go test -timeout 90s -race -v ./...; exit 1; }
    ```
    `-count=1` is required on both invocations: it defeats Go's test _result_
    cache, so neither run can report a stored pass in place of running the
    tests. It leaves the build cache alone, so it costs the runtime of the suite
    and no recompilation.
    That cache is Go's own, separate from Docker's layer cache. Go stores a
    passing result in its cache directory (`GOCACHE`), and when the same tests
    run again on unchanged code it prints that result, marked `(cached)`,
    without running them. That matters on a developer's machine, where this
    target runs and the directory lasts from one run to the next. The `test`
    phase of the `Dockerfile` needs no `-count=1`: its base image holds no
    result for this repo's tests and nothing before its `go test` step runs a
    test, so there is nothing to replay. `--no-cache` (above) is what makes that
    step run on an unchanged tree.
    Python example:
    ```makefile
@@ -356,84 +244,10 @@ style conventions are in separate documents:
  must be in `.gitignore`. No exceptions.
 - `.gitignore` should be comprehensive from the start: OS files (`.DS_Store`),
-  editor files (`.swp`, `*~`), in-repo agent scratch directories (`.claude/`),
+  editor files (`.swp`, `*~`), language build artifacts, and `node_modules/`.
-  language build artifacts, and `node_modules/`. Fetch the standard `.gitignore`
+  Fetch the standard `.gitignore` from
-  from `https://git.eeqj.de/sneak/prompts/raw/branch/main/.gitignore` when
+  `https://git.eeqj.de/sneak/prompts/raw/branch/main/.gitignore` when setting up
-  setting up a new repo. These patterns are written to `.gitignore`'s own
+  a new repo.
  semantics, in which an unanchored pattern already matches at every depth; they
  are not a `.dockerignore` and must not be transplanted into one unmodified.
 - **`.dockerignore` does not use `.gitignore` semantics, and copying patterns
  across unmodified leaves secrets in the build context.** Docker matches with
  `moby/patternmatcher`: `filepath.Match` semantics plus a `**` extension, so
  `*` does not cross `/` and a pattern without a leading `**/` is anchored at
  the build-context root. A `.dockerignore` listing `.env`, `*.pem` and `*.key`
  therefore excludes only the copies at the repository root, while `config/.env`
  and `certs/server.key` still reach the context and can land in an image layer
  — which is more dangerous than a short file with no secret patterns at all,
  because it reads as solved and stops anyone looking. Give every
  depth-independent pattern the `**/` prefix and leave only genuinely
  root-anchored entries unprefixed: `.claude`, and the repo's own host-built
  binary, written `/myapp` and never `**/myapp`, which would also match
  `cmd/myapp/` and delete the package directory from the context. Matching is
  case-sensitive, and an ALL-CAPS twin per pattern still misses `Server.Key`, so
  secret names use character ranges — `**/*.[kK][eE][yY]`, `**/*.[pP][eE][mM]`,
  and likewise for `.envrc` and the extensionless SSH keys. Where such a pattern
  also catches something the build needs, re-include it with a negation
  (`!docs/example.env`); deleting the pattern reopens the exposure for every
  other file it covers. Fetch the standard `.dockerignore` from
  `https://git.eeqj.de/sneak/prompts/raw/branch/main/.dockerignore` and extend
  it with the repo's own artifacts.
 - **In-repo agent scratch belongs in both files, written to each file's own
  semantics.** `.claude/` holds one worktree per in-flight agent — an entire
  additional checkout of the repo — so under `COPY . .` the build context
  inflates by a multiple of the repo and another session's unreviewed work can
  be copied into an image layer. In `.gitignore` the entry is `.claude/`,
  unanchored. In `.dockerignore` it is `.claude`, anchored and with **no** `**/`
  prefix, because the prefixed form would also delete any nested directory of
  that name from the build. Anchoring carries a known gap that the canonical
  `.dockerignore` states in its own comment, since consuming repos receive the
  file and not the tracker: the directory is created in the agent's working
  directory, so a repo running agents in subdirectories still ships
  `services/api/.claude/` and must add its own anchored entry there.
 - **A plain `docker build .` of a clone stamps the version that
  `git describe --tags --always` gives**, derived from the `.git` in the build
  context as the canonical `Dockerfile` above shows. Without its failure check,
  a missing `git` or an unreadable checkout would leave `-X main.Version=` empty
  and the build would still exit 0. `script/docker` and `script/cibuild` pass
  the version they compute on the host; it takes precedence. They do this
  byte-identically across repos:
    ```sh
    # Own line: a failing command substitution inside an argument does not
    # trip `set -e`, so the inline form degrades to an empty constant.
    version="$(git describe --tags --always --dirty 2>/dev/null || true)"
    [ -n "$version" ] || version="unknown"
    docker build --no-cache \
        --build-arg VERSION="$version" \
        -t "$(script/projectname)" .
    ```
    `--always` makes an untagged repo yield an abbreviated commit hash rather
    than failing, and the `[ -n "$version" ]` line is the single place the
    fallback is applied — a live check that fires on a build from an export with
    no `.git` and on a repository with no commits yet. Do not fold it into the
    substitution as `|| echo unknown`, which makes the guard unreachable. The
    Dockerfile's side is `ARG VERSION` in the stage that compiles, declared
    there because `ARG` is stage-scoped; passing `VERSION` to a repo whose
    Dockerfile declares no such `ARG` is ignored and costs nothing, which is why
    the scripts stay byte-identical. One consequence for CI: the standard
    checkout action clones shallow and fetches no tags, so a repo that embeds a
    tag-derived version must set `fetch-depth: 0` on its checkout step.
 - **Verify `.dockerignore` by enumerating the image, not by reading the
  patterns.** Plant files at the root _and_ at least two directories deep, build
  a probe image that does `COPY . .`, and list what actually landed
  (`docker run --rm --entrypoint find IMAGE /app`). The `transferring context`
  size is not a substitute: a nested secret is a few bytes, and BuildKit
  transfers only the delta from the previous build.
 - **No build artifacts in version control.** Code-derived data (compiled
  bundles, minified output, generated assets) must never be committed to the
@@ -455,45 +269,9 @@ style conventions are in separate documents:
  byte-identical, so that no repo can quietly loosen its own linting. Linter
  configuration changes are made to the canonical copy in the `prompts` repo and
  reach consuming repos by re-vendoring; an agent may open a PR against
-  canonical, which only the user merges. One list is exempt from byte-identity,
+  canonical, which only the user merges. The canonical golangci-lint version is
-  because it cannot be written once for every repo: the `deny` list of the
+  v2.12.2 (released 2026-05-06), installed commit-pinned via
-  `test-support` depguard rule, where a repo names its own test-support packages
+  `go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@c0d3ddc9cf3faa61a4e378e879ece580256d76e5`.
  by full import path. A repo adds entries there and changes nothing else, and a
  re-vendor carries its entries forward. The canonical golangci-lint version is
  v2.14.0 (released 2026-09-24), pinned as the digest of the lint phase's base
  image
  (`golangci/golangci-lint@sha256:ad862ba6b3798cbe0fd9fd7408d498fd74fbd2623a92406b2fd3898faf0bf98f`,
  which reports `2.14.0 built with go1.27.0 from 114493f9`). A module's `go`
  directive must not name a newer Go minor version than the one golangci-lint
  was built with, or golangci-lint refuses to lint it: this release lints
  `go 1.27.1` but not `go 1.28`. That digest is the only pin, since no repo
  installs golangci-lint on the host. A repo sets the lint phase digest to the
  one named here and re-vendors `.golangci.yml` in the same commit, whichever of
  the two prompted the change: the canonical copy can name linters that an older
  golangci-lint rejects, and a newer golangci-lint can add linters that
  `default: all` switches on until the canonical copy disables them.
 - **`script/bootstrap` installs a pinned tool by comparing versions, never by
  testing presence.** An `if ! command -v <tool>; then install; fi` guard tests
  `PATH` only, so on an already-provisioned machine the pin is inert and a
  version bump is a silent no-op — while the Dockerfile, installing into a clean
  image, gets the pinned version, so a local `make check` and `make docker` can
  disagree about what the tool even is. The canonical form:
    - compares the installed version against the pin over the **whole** version
      token; a parser that stops at the first `-` reports `2.12.2` for a host
      running `2.12.2-rc1` and skips the install;
    - treats absent, non-zero, empty or unrecognised `--version` output as a
      mismatch, so the failure direction is a redundant install and never a
      skipped one;
    - after installing, re-resolves the binary the way callers do — `hash -r`,
      then through `PATH`, not through the directory the installer wrote to —
      and fails naming the resolved path, since an install that a shadowing
      binary hides succeeds while changing nothing any caller sees;
    - is actually called, and prints the version on both success paths: a
      function defined and never invoked has the same exit status and the same
      empty output as one that worked.
    Keep it POSIX sh: no arrays, no `[[`, no `grep -P`.
 - When pinning images or packages by hash, add a comment above the reference
  with the version and date (YYYY-MM-DD).
@@ -607,10 +385,10 @@ style conventions are in separate documents:
  settings.
 - Avoid putting files in the repo root unless necessary. Root should contain
-  only project-level config files (`README.md`, `AGENTS.md`, `Makefile`,
+  only project-level config files (`README.md`, `Makefile`, `Dockerfile`,
-  `Dockerfile`, `LICENSE`, `.gitignore`, `.editorconfig`, `REPO_POLICIES.md`,
+  `LICENSE`, `.gitignore`, `.editorconfig`, `REPO_POLICIES.md`, and
-  and language-specific config). Everything else goes in a subdirectory.
+  language-specific config). Everything else goes in a subdirectory. Canonical
-  Canonical subdirectory names:
+  subdirectory names:
    - `bin/` — executable scripts and tools
    - `cmd/` — Go command entrypoints; thin only: one `main.go` per binary whose
      body is a single call into `internal/` or `pkg/`, no project logic in
@@ -641,7 +419,3 @@ style conventions are in separate documents:
    - Go: `go.mod`, `go.sum`, `.golangci.yml`
    - JS: `package.json`, `yarn.lock`, `.prettierrc`, `.prettierignore`
    - Python: `pyproject.toml`
 - Guidance for coding agents lives in one `AGENTS.md` at the repository root. It
  is never committed under a file or directory named after one agent tool, such
  as `CLAUDE.md` or `.claude/`, and never split into separate memory files.
@@ -4,7 +4,7 @@ package main
 import (
 	"os"
-	"sneak.berlin/go/keyfunc/internal/cli"
+	"git.eeqj.de/sneak/keyfunc/internal/cli"
 )
 func main() {
@@ -1,4 +1,4 @@
-module sneak.berlin/go/keyfunc
+module git.eeqj.de/sneak/keyfunc
 go 1.26.0
@@ -5,9 +5,9 @@ import (
 	"strings"
 	"testing"
 	"git.eeqj.de/sneak/keyfunc/internal/agekey"
 	"git.eeqj.de/sneak/keyfunc/internal/derive"
 	"github.com/stretchr/testify/require"
 	"sneak.berlin/go/keyfunc/internal/agekey"
 	"sneak.berlin/go/keyfunc/internal/derive"
 )
 // The recipients the example mnemonic produces at the first two
@@ -5,10 +5,10 @@ import (
 	"errors"
 	"fmt"
 	"git.eeqj.de/sneak/keyfunc/internal/derive"
 	"git.eeqj.de/sneak/secret/pkg/bip85"
 	"github.com/btcsuite/btcd/btcutil/hdkeychain"
 	bip39 "github.com/tyler-smith/go-bip39"
 	"sneak.berlin/go/keyfunc/internal/derive"
 )
 // english is the number BIP-85 gives the English word list.
@@ -4,11 +4,11 @@ import (
 	"strings"
 	"testing"
 	"git.eeqj.de/sneak/keyfunc/internal/childmnemonic"
 	"git.eeqj.de/sneak/keyfunc/internal/derive"
 	"github.com/btcsuite/btcd/btcutil/hdkeychain"
 	"github.com/stretchr/testify/require"
 	bip39 "github.com/tyler-smith/go-bip39"
 	"sneak.berlin/go/keyfunc/internal/childmnemonic"
 	"sneak.berlin/go/keyfunc/internal/derive"
 )
 // The lengths the tool offers, and one it does not.
@@ -3,33 +3,17 @@
 package age
 import (
 	"context"
 	"errors"
 	"fmt"
 	"io"
 	"os"
 	"path/filepath"
 	"time"
 	"git.eeqj.de/sneak/keyfunc/internal/agekey"
 	"git.eeqj.de/sneak/keyfunc/internal/cli/options"
 	"git.eeqj.de/sneak/keyfunc/internal/derive"
 	"github.com/spf13/cobra"
 	"sneak.berlin/go/keyfunc/internal/agekey"
 	"sneak.berlin/go/keyfunc/internal/cli/options"
 	"sneak.berlin/go/keyfunc/internal/cli/signals"
 	"sneak.berlin/go/keyfunc/internal/derive"
 )
 // ErrInterrupted is returned when SIGINT, SIGTERM or SIGHUP came before
 // the file --output names was put in place.
 var ErrInterrupted = errors.New(
 	"interrupted by a signal; the output file was left as it was",
 )
 // signalWait is how long after the work has ended a signal still keeps
 // the new file from being put in place. Ctrl-C on "producer | keyfunc
 // age encrypt -o file" ends the producer as well, and the end of the
 // input can reach the work a moment before the signal reaches the tool.
 const signalWait = 100 * time.Millisecond
 // Command returns the age command and everything under it.
 func Command() *cobra.Command {
 	group := &cobra.Command{
@@ -144,9 +128,8 @@ func runDecrypt(cmd *cobra.Command, args []string) error {
 	return through(cmd, args, key.Decrypt)
 }
-// through opens the input the arguments ask for and hands it to the
+// through opens the input and the output the arguments ask for, hands
-// work, with the file --output names to write to, or the command's own
+// them to the work, and finishes the output afterwards either way.
 // output when it names none.
 func through(
 	cmd *cobra.Command, args []string,
 	work func(io.Writer, io.Reader) error,
@@ -158,16 +141,14 @@ func through(
 	defer closeSrc()
-	name, err := cmd.Flags().GetString("output")
+	dst, done, err := output(cmd)
 	if err != nil {
-		return fmt.Errorf("reading the output file: %w", err)
+		return err
 	}
-	if name == "" {
+	err = work(dst, src)
 		return work(cmd.OutOrStdout(), src)
 	}
-	return output(name, src, work)
+	return done(err)
 }
 // input returns what to read from: the named file, or the command's
@@ -186,44 +167,35 @@ func input(cmd *cobra.Command, args []string) (io.Reader, func(), error) {
 	return file, func() { _ = file.Close() }, nil
 }
-// output has the work write a new file beside the named one, and puts
+// output returns what to write to: a new file beside the one --output
-// the new file in the named file's place only when the work succeeded,
+// names, or the command's own output when it names none. The second
-// so a file that is already there survives a run that failed.
+// result finishes the write, and is given whatever the work returned:
-//
+// the new file takes the named file's place only when the work
-// Meanwhile SIGINT, SIGTERM and SIGHUP are caught, as signals.Context
+// succeeded, so a file that is already there survives a run that
-// does. One that comes while the work runs, or within signalWait after
+// failed.
-// it has ended, wins: the new file is removed and ErrInterrupted
+func output(cmd *cobra.Command) (io.Writer, func(error) error, error) {
-// returned at once, without waiting for the work, which may be blocked
+	name, err := cmd.Flags().GetString("output")
-// reading its input.
+	if err != nil {
-func output(
+		return nil, nil, fmt.Errorf("reading the output file: %w", err)
-	name string, src io.Reader, work func(io.Writer, io.Reader) error,
+	}
-) error {
+
-	interrupted, stop := signals.Context(context.Background())
+	if name == "" {
-	defer stop()
+		return cmd.OutOrStdout(), func(failed error) error {
 			return failed
 		}, nil
 	}
 	// The file is made in the same directory so that putting it in
 	// place is a rename and never a copy, and it is readable only by
 	// its owner, which is the mode it keeps once renamed.
 	file, err := os.CreateTemp(filepath.Dir(name), filepath.Base(name)+".")
 	if err != nil {
-		return fmt.Errorf("creating a file beside %s: %w", name, err)
+		return nil, nil, fmt.Errorf("creating a file beside %s: %w", name, err)
 	}
-	worked := make(chan error, 1)
+	return file, func(failed error) error {
 	go func() { worked <- work(file, src) }()
 	select {
 	case failed := <-worked:
 		select {
 		case <-interrupted.Done():
 		case <-time.After(signalWait):
 		return finish(file, name, failed)
-		}
+	}, nil
 	case <-interrupted.Done():
 	}
 	return finish(file, name, ErrInterrupted)
 }
 // finish closes the new file and puts it in the named file's place, or
@@ -1,18 +1,14 @@
 package cli_test
 import (
 	"io"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"strings"
 	"syscall"
 	"testing"
 	"time"
 	"git.eeqj.de/sneak/keyfunc/internal/agekey"
 	"git.eeqj.de/sneak/keyfunc/internal/mnemonic"
 	"github.com/stretchr/testify/require"
 	"sneak.berlin/go/keyfunc/internal/agekey"
 	"sneak.berlin/go/keyfunc/internal/mnemonic"
 )
 func TestTheAgeCommandsPrintTheKey(t *testing.T) {
@@ -94,140 +90,6 @@ func TestARefusedDecryptionLeavesTheOutputFileAlone(t *testing.T) {
 	require.Equal(t, "what was already there\n", string(kept))
 }
 func TestASignalStopsAnEncryptionAndLeavesNoFile(t *testing.T) {
 	t.Setenv(mnemonic.Variable, example())
 	for _, ending := range []os.Signal{
 		syscall.SIGTERM, syscall.SIGINT, syscall.SIGHUP,
 	} {
 		interrupted(t, ending, "encrypt", "the start of the secret\n", false)
 	}
 }
 func TestASignalStopsADecryptionAndLeavesNoFile(t *testing.T) {
 	t.Setenv(mnemonic.Variable, example())
 	// All of an encryption but its last byte, so the tool reads the
 	// header and then waits for the rest.
 	sealed := run(t, "age", "encrypt", written(t, "notes.txt", "the secret\n"))
 	cut := sealed[:len(sealed)-1]
 	for _, ending := range []os.Signal{
 		syscall.SIGTERM, syscall.SIGINT, syscall.SIGHUP,
 	} {
 		interrupted(t, ending, "decrypt", cut, false)
 	}
 }
 func TestASignalAsTheInputEndsLeavesNoFile(t *testing.T) {
 	t.Setenv(mnemonic.Variable, example())
 	sealed := run(t, "age", "encrypt", written(t, "notes.txt", "the secret\n"))
 	// Ctrl-C on "producer | keyfunc age encrypt -o file" ends the
 	// producer too, so the input ends just as the signal comes, with
 	// enough of it in hand for a whole encryption or decryption. Which
 	// of the two reaches the tool first varies, so it is tried often.
 	for range 25 {
 		interrupted(t, syscall.SIGINT, "encrypt", "the start of the secret\n", true)
 		interrupted(t, syscall.SIGINT, "decrypt", sealed, true)
 	}
 }
 func TestAnEncryptionStartedUnderNohupSurvivesAHangup(t *testing.T) {
 	t.Setenv(mnemonic.Variable, example())
 	directory := t.TempDir()
 	named := filepath.Join(directory, "notes")
 	// nohup starts the tool with SIGHUP ignored. A tool that caught it
 	// anyway would turn it back on and be ended by it.
 	command, producer := writing(
 		t, directory, "the secret\n",
 		"nohup", os.Args[0], "age", "encrypt", "-o", named,
 	)
 	require.NoError(t, command.Process.Signal(syscall.SIGHUP))
 	require.NoError(t, producer.Close())
 	waitForTool(t, "SIGHUP under nohup", command)
 	require.Equal(t, 0, command.ProcessState.ExitCode())
 	left, err := os.ReadDir(directory)
 	require.NoError(t, err)
 	require.Len(t, left, 1)
 	require.Equal(t, "the secret\n", run(t, "age", "decrypt", named))
 }
 // interrupted runs "age encrypt -o" or "age decrypt -o", as the
 // operation says, writing into a directory of its own, and once it has
 // begun writing sends it the signal, then ends the input if endInput
 // says so and otherwise leaves it open. The tool has to end with status
 // 1 and leave the directory empty. A tool that went on reading would
 // not end until the input did; one that did not remove the file it was
 // writing would leave it there, with what it had written so far; one
 // that put that file in place because the input ended would leave the
 // named file.
 func interrupted(
 	t *testing.T, signal os.Signal, operation, input string, endInput bool,
 ) {
 	t.Helper()
 	name := operation + " " + signal.String()
 	directory := t.TempDir()
 	command, producer := writing(
 		t, directory, input,
 		os.Args[0], "age", operation, "-o", filepath.Join(directory, "notes"),
 	)
 	require.NoError(t, command.Process.Signal(signal))
 	if endInput {
 		require.NoError(t, producer.Close())
 	}
 	waitForTool(t, name, command)
 	require.Equal(t, 1, command.ProcessState.ExitCode(), name)
 	left, err := os.ReadDir(directory)
 	require.NoError(t, err)
 	require.Empty(t, left, name)
 }
 // writing starts argv, the tool told to write into directory, as a
 // subprocess reading the input from a pipe, and returns once the tool
 // has begun writing the file beside the one it was named. The pipe is
 // left open for the caller to end.
 func writing(
 	t *testing.T, directory, input string, argv ...string,
 ) (*exec.Cmd, io.WriteCloser) {
 	t.Helper()
 	//nolint:gosec // this test's own binary as the tool, or nohup running it
 	command := exec.CommandContext(t.Context(), argv[0], argv[1:]...)
 	command.Env = append(os.Environ(), runAsTool+"=1")
 	producer, err := command.StdinPipe()
 	require.NoError(t, err)
 	require.NoError(t, command.Start())
 	_, err = io.WriteString(producer, input)
 	require.NoError(t, err)
 	// The file beside the named one is made once the mnemonic has been
 	// read, before any input is.
 	require.Eventually(t, func() bool {
 		entries, err := os.ReadDir(directory)
 		return err == nil && len(entries) > 0
 	}, 5*time.Second, 5*time.Millisecond)
 	return command, producer
 }
 // written puts the contents in a file of that name in a directory of
 // this test's own and returns the path to it.
 func written(t *testing.T, name, contents string) string {
@@ -5,52 +5,28 @@ import (
 	"errors"
 	"fmt"
 	"os"
 	"runtime/debug"
 	"git.eeqj.de/sneak/keyfunc/internal/cli/age"
 	"git.eeqj.de/sneak/keyfunc/internal/cli/mnemonic"
 	"git.eeqj.de/sneak/keyfunc/internal/cli/options"
 	"git.eeqj.de/sneak/keyfunc/internal/cli/ssh"
 	"github.com/spf13/cobra"
 	"sneak.berlin/go/keyfunc/internal/cli/age"
 	"sneak.berlin/go/keyfunc/internal/cli/mnemonic"
 	"sneak.berlin/go/keyfunc/internal/cli/options"
 	"sneak.berlin/go/keyfunc/internal/cli/ssh"
 )
-// devVersion is what Version holds until a build stamps a real one.
+// Version is what --version prints. The build sets it.
 const devVersion = "dev"
 // Version is what --version prints. make build stamps it with -ldflags.
 //
 //nolint:gochecknoglobals // set at build time with -ldflags
-var Version = devVersion
+var Version = "dev"
 // resolveVersion chooses what --version reports. A value stamped at
 // build time wins. Otherwise, for a binary from go install, the module
 // version recorded in the build info is used, unless that is empty or
 // the "(devel)" of a local build. When neither names a version, the
 // "dev" fallback stays.
 func resolveVersion(stamped string, info *debug.BuildInfo) string {
 	if stamped != devVersion {
 		return stamped
 	}
 	if info != nil && info.Main.Version != "" &&
 		info.Main.Version != "(devel)" {
 		return info.Main.Version
 	}
 	return devVersion
 }
 // Root returns the whole command tree.
 func Root() *cobra.Command {
 	info, _ := debug.ReadBuildInfo()
 	root := &cobra.Command{
 		Use:   "keyfunc",
 		Short: "derive key pairs from a BIP-39 mnemonic",
 		Long: "keyfunc turns a BIP-39 mnemonic into key pairs that can " +
 			"be recreated from that mnemonic at any time. The same " +
 			"mnemonic, key type and index always give the same key.",
-		Version:       resolveVersion(Version, info),
+		Version:       Version,
 		SilenceUsage:  true,
 		SilenceErrors: true,
 	}
@@ -66,21 +42,14 @@ func Root() *cobra.Command {
 // status of its own, which "ssh to" uses to hand on the status ssh
 // ended with. ssh has already said whatever it had to say in that
 // case, so nothing more is printed.
 //
 // SIGINT, SIGTERM and SIGHUP end the tool at once, as they end any Go
 // program, so a command waiting at the mnemonic prompt or reading what
 // it encrypts or decrypts goes no further. The exceptions catch the
 // signals to clean up first: "ssh to" and "ssh install" while they
 // have ssh or sftp running, so the child ends and their own cleanup
 // still runs, and "age encrypt -o" and "age decrypt -o" while they
 // write, so the unfinished file is removed.
 func Main() int {
 	err := Root().Execute()
 	if err == nil {
 		return 0
 	}
-	if passed, ok := errors.AsType[ssh.StatusError](err); ok {
+	var passed ssh.StatusError
 	if errors.As(err, &passed) {
 		return passed.Status
 	}
@@ -5,13 +5,13 @@ import (
 	"strings"
 	"testing"
 	"git.eeqj.de/sneak/keyfunc/internal/childmnemonic"
 	"git.eeqj.de/sneak/keyfunc/internal/cli"
 	"git.eeqj.de/sneak/keyfunc/internal/derive"
 	"git.eeqj.de/sneak/keyfunc/internal/mnemonic"
 	"github.com/stretchr/testify/require"
 	bip39 "github.com/tyler-smith/go-bip39"
 	"golang.org/x/crypto/ssh"
 	"sneak.berlin/go/keyfunc/internal/childmnemonic"
 	"sneak.berlin/go/keyfunc/internal/cli"
 	"sneak.berlin/go/keyfunc/internal/derive"
 	"sneak.berlin/go/keyfunc/internal/mnemonic"
 )
 // The two lines the README says the example mnemonic produces.
@@ -22,11 +22,6 @@ const (
 		"0I4FKs+eVUulTPHfk9VtXw1tMF"
 )
 // The child mnemonic the README says the example mnemonic gives at
 // index 0.
 const childZero = "prosper short ramp prepare exchange stove life " +
 	"snack client enough purpose fold"
 // The two child mnemonic lengths the tests ask for.
 const (
 	twelve     = 12
@@ -50,28 +45,6 @@ func TestTheReadmeTestVectors(t *testing.T) {
 		vectorOne+" keyfunc/ssh/1",
 		strings.TrimSpace(run(t, "ssh", "pub", "-n", "1")),
 	)
 	require.Equal(t,
 		childZero, strings.TrimSpace(run(t, "mnemonic", "-n", "0")),
 	)
 }
 func TestTheSpacingBetweenTheWordsDoesNotChangeTheKeys(t *testing.T) {
 	words := strings.Fields(example())
 	for name, spaced := range map[string]string{
 		"one word per line": strings.Join(words, "\n"),
 		"double spaces":     strings.Join(words, "  "),
 		"tabs":              strings.Join(words, "\t"),
 	} {
 		t.Run(name, func(t *testing.T) {
 			t.Setenv(mnemonic.Variable, spaced)
 			require.Equal(t,
 				vectorZero+" keyfunc/ssh/0",
 				strings.TrimSpace(run(t, "ssh", "pub", "-n", "0")),
 			)
 		})
 	}
 }
 func TestTheCommentCanBeChosen(t *testing.T) {
@@ -4,10 +4,10 @@ package mnemonic
 import (
 	"fmt"
 	"git.eeqj.de/sneak/keyfunc/internal/childmnemonic"
 	"git.eeqj.de/sneak/keyfunc/internal/cli/options"
 	"git.eeqj.de/sneak/keyfunc/internal/derive"
 	"github.com/spf13/cobra"
 	"sneak.berlin/go/keyfunc/internal/childmnemonic"
 	"sneak.berlin/go/keyfunc/internal/cli/options"
 	"sneak.berlin/go/keyfunc/internal/derive"
 )
 // Command returns the mnemonic command.
@@ -5,8 +5,8 @@ package options
 import (
 	"fmt"
 	"git.eeqj.de/sneak/keyfunc/internal/mnemonic"
 	"github.com/spf13/cobra"
 	"sneak.berlin/go/keyfunc/internal/mnemonic"
 )
 // Add gives a command the flags that every command has. They are
@@ -1,34 +0,0 @@
 // Package signals catches the signals that end the tool, for the
 // commands that clean up before they end.
 package signals
 import (
 	"context"
 	"os"
 	"os/signal"
 	"syscall"
 )
 // Context is signal.NotifyContext for SIGINT, SIGTERM and SIGHUP: the
 // context it returns is cancelled when one of them arrives, and stop
 // stops catching them. It leaves out any of the three the tool was
 // started with set to be ignored, as nohup does with SIGHUP, because
 // catching a signal turns an ignored one back on and would end a run
 // that was meant to survive it.
 func Context(parent context.Context) (context.Context, context.CancelFunc) {
 	endings := []os.Signal{syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP}
 	caught := make([]os.Signal, 0, len(endings))
 	for _, ending := range endings {
 		if !signal.Ignored(ending) {
 			caught = append(caught, ending)
 		}
 	}
 	// Given no signals at all, NotifyContext would catch every one.
 	if len(caught) == 0 {
 		return context.WithCancel(parent)
 	}
 	return signal.NotifyContext(parent, caught...)
 }
@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"crypto/rand"
 	"encoding/hex"
 	"errors"
 	"fmt"
 	"os"
 	"os/exec"
@@ -13,7 +12,6 @@ import (
 	"strings"
 	"github.com/spf13/cobra"
 	"sneak.berlin/go/keyfunc/internal/cli/signals"
 )
 // Where the key goes on the host and what the file it arrives in is
@@ -34,12 +32,6 @@ const (
 	localMode     = 0o600
 )
 // ErrCannotEnter is the refusal of a host whose .ssh is there but
 // cannot be entered, so that nothing in it can be read or written.
 var ErrCannotEnter = errors.New(
 	"~/.ssh is there on the host but cannot be entered",
 )
 // install returns the command that adds the public key to a host.
 func install() *cobra.Command {
 	cmd := &cobra.Command{
@@ -63,14 +55,6 @@ func install() *cobra.Command {
 				return err
 			}
 			// From here on a signal cancels the context, which
 			// sftp runs under, instead of ending the tool, so sftp
 			// ends and the working directory is still removed.
 			ctx, stop := signals.Context(cmd.Context())
 			defer stop()
 			cmd.SetContext(ctx)
 			return add(cmd, args[0], args[1:], line)
 		},
 	}
@@ -92,7 +76,7 @@ func add(cmd *cobra.Command, host string, options []string, line string) error {
 	defer func() { _ = os.RemoveAll(work) }()
-	content, present, err := fetch(cmd, host, options,
+	content, err := fetch(cmd, host, options,
 		filepath.Join(work, "authorized_keys"),
 	)
 	if err != nil {
@@ -104,18 +88,16 @@ func add(cmd *cobra.Command, host string, options []string, line string) error {
 		return write(cmd, "already present\n")
 	}
-	return upload(cmd, host, options, work, merged, present)
+	return upload(cmd, host, options, work, merged)
 }
 // upload writes the new file to the host and renames it over
 // authorized_keys, which is the step that either happens or does not.
 // Nothing is removed when a step fails: the file left behind is named
-// so that it can be looked at and cleared away by hand. The directory
+// so that it can be looked at and cleared away by hand.
 // is made and set to its mode only when the read found none: an .ssh
 // that was already there is left with the mode it had.
 func upload(
 	cmd *cobra.Command, host string, options []string,
-	work, merged string, present bool,
+	work, merged string,
 ) error {
 	local := filepath.Join(work, "authorized_keys.merged")
@@ -129,24 +111,14 @@ func upload(
 		return err
 	}
-	var batch []string
+	// The mkdir may fail: the directory is usually there already.
-
+	said, err := session(cmd, host, options, []string{
 	if !present {
 		// The mkdir is allowed to fail in case the directory appeared
 		// between the read and now; the chmod then sets its mode.
 		batch = append(batch,
 		"-mkdir " + directory,
 		"chmod " + directoryMode + " " + directory,
 		)
 	}
 	batch = append(batch,
 		"put " + quoted(local) + " " + sidecar,
 		"chmod " + fileMode + " " + sidecar,
 		"rename " + sidecar + " " + authorized,
-	)
+	})
 	said, err := session(cmd, host, options, batch)
 	if err != nil {
 		// sftp echoes each command as it runs it and stops at the
 		// first that fails, so the name is in what it said only once
@@ -182,7 +154,6 @@ func session(
 	//nolint:gosec // the options are the user's own, meant for sftp
 	command := exec.CommandContext(cmd.Context(), "sftp", argv...)
 	command.Env = childEnv()
 	command.Stdin = strings.NewReader(strings.Join(batch, "\n") + "\n")
 	command.Stdout = &said
 	command.Stderr = &said
@@ -214,91 +185,31 @@ func merge(content, line string) (string, bool) {
 }
 // fetch brings the host's authorized_keys into the given path and
-// returns what is in it, and whether the .ssh directory was already
+// returns what is in it. A host that has no such file reads as empty,
-// there. The one session lists .ssh, then .ssh/., and then gets the
+// but only when that is what sftp said about it: a file that is there
-// file, so the listings settle the state of the directory before the
+// and cannot be read fails the run, because writing back over it
-// get is read.
+// would leave the host with the new key and nothing else.
 //
 // The file reads as empty in just two cases: sftp reported .ssh itself
 // as not there, or both listings succeeded and the get then reported
 // the file as not there. Anything else — a listing refused, the file
 // there but unreadable, the connection down — fails the run and writes
 // nothing, because writing back over what was not read would leave the
 // host with the new key and nothing else. sftp cannot tell a missing
 // file from one in a directory it cannot enter, so the listings do: a
 // directory that is there but cannot be read fails the first, and one
 // that can be read but not entered fails the second, because nothing in
 // it can be looked up, not even ".". The first listing of such a
 // directory comes up empty, as the server leaves out every name it
 // cannot look up.
 func fetch(
 	cmd *cobra.Command, host string, options []string, into string,
-) (string, bool, error) {
+) (string, error) {
 	said, err := session(cmd, host, options, []string{
 		"ls -1 " + directory,
 		"ls -1 " + directory + "/.",
 		"get " + authorized + " " + quoted(into),
 	})
 	if err != nil {
 		if listingNotFound(said, directory) {
 			return "", false, nil
 		}
 		if listingNotFound(said, directory+"/.") {
 			return "", false, ErrCannotEnter
 		}
 		if absent(said) {
-			return "", true, nil
+			return "", nil
 		}
-		return "", false, err
+		return "", err
 	}
 	//nolint:gosec // the path is a temporary file of the tool's own
 	content, err := os.ReadFile(into)
 	if err != nil {
-		return "", false, fmt.Errorf("reading the fetched file: %w", err)
+		return "", fmt.Errorf("reading the fetched file: %w", err)
 	}
-	return string(content), true, nil
+	return string(content), nil
 }
 // listingNotFound says whether sftp reported the path it was asked to
 // list as not being there. For .ssh that is the one listing failure
 // read as a host that has no authorized_keys yet; for .ssh/., once .ssh
 // itself has been listed, it is a .ssh that is there but cannot be
 // entered. The reading is taken only from the line in which sftp
 // reports on that path: any other failure of a listing, in particular a
 // directory that is there but cannot be read, is left as a failure, so
 // that no key is written to a host whose keys were never read.
 func listingNotFound(said, path string) bool {
 	for line := range strings.Lines(said) {
 		named, is := reportedCannotList(strings.TrimSpace(line))
 		if is && (named == path || strings.HasSuffix(named, "/"+path)) {
 			return true
 		}
 	}
 	return false
 }
 // reportedCannotList returns the path an sftp line reports it cannot
 // list for want of it, and whether the line is such a report. The
 // client writes this one wording when it cannot look up the path a
 // listing names, giving the path the server expanded.
 func reportedCannotList(line string) (string, bool) {
 	const (
 		before = `Can't ls: "`
 		after  = `" not found`
 	)
 	if !strings.HasPrefix(line, before) ||
 		!strings.HasSuffix(line, after) {
 		return "", false
 	}
 	return strings.TrimSuffix(strings.TrimPrefix(line, before), after), true
 }
 // absent says whether sftp reported the file that was asked for as
@@ -10,7 +10,6 @@ import "testing"
 const (
 	echoed = `sftp> get .ssh/authorized_keys "/tmp/keyfunc/authorized_keys"
 `
 	listed  = "sftp> ls -1 .ssh\n"
 	warning = `Warning: Identity file /gone not accessible: ` +
 		"No such file or directory.\n"
 )
@@ -77,65 +76,3 @@ func TestAbsenceIsReadOnlyFromWhatSFTPSaidAboutAuthorizedKeys(t *testing.T) {
 		})
 	}
 }
 // TestTheDirectoryIsReadAsAbsentOnlyFromTheListingSayingSo holds the
 // wordings the OpenSSH client was seen to use when a listing fails: a
 // directory it cannot find is reported one way, and one it cannot read
 // another, and only the first is read as a host with no .ssh yet. A
 // .ssh that can be read but not entered lists as empty, and the
 // listing of .ssh/. that follows reports that path, not .ssh, as not
 // found.
 func TestTheDirectoryIsReadAsAbsentOnlyFromTheListingSayingSo(t *testing.T) {
 	t.Parallel()
 	listings := map[string]struct {
 		said string
 		want bool
 	}{
 		"the directory is not there": {
 			said: listed + `Can't ls: "/home/someone/.ssh" not found` + "\n",
 			want: true,
 		},
 		"the directory is not there, named as it was asked for": {
 			said: listed + `Can't ls: ".ssh" not found` + "\n",
 			want: true,
 		},
 		"the directory is not there and an identity file is not either": {
 			said: warning + listed +
 				`Can't ls: "/home/someone/.ssh" not found` + "\n",
 			want: true,
 		},
 		"the directory is there and cannot be read": {
 			said: listed +
 				`remote readdir("/home/someone/.ssh/"): Permission denied` + "\n",
 			want: false,
 		},
 		"the directory is there and cannot be entered": {
 			said: listed + "sftp> ls -1 .ssh/.\n" +
 				`Can't ls: "/home/someone/.ssh/." not found` + "\n",
 			want: false,
 		},
 		"some other directory is not there": {
 			said: listed + `Can't ls: "/home/someone/.config" not found` + "\n",
 			want: false,
 		},
 		"the connection did not come up": {
 			said: "ssh: connect to host example.com port 22: " +
 				"Connection refused\nConnection closed\n",
 			want: false,
 		},
 	}
 	for name, listing := range listings {
 		t.Run(name, func(t *testing.T) {
 			t.Parallel()
 			if listingNotFound(listing.said, directory) != listing.want {
 				t.Errorf(
 					"read as absent: %t, wanted %t, from:\n%s",
 					!listing.want, listing.want, listing.said,
 				)
 			}
 		})
 	}
 }
@@ -3,14 +3,11 @@ package ssh
 import (
 	"fmt"
 	"os"
 	"strings"
 	"git.eeqj.de/sneak/keyfunc/internal/cli/options"
 	"git.eeqj.de/sneak/keyfunc/internal/derive"
 	"git.eeqj.de/sneak/keyfunc/internal/sshkey"
 	"github.com/spf13/cobra"
 	"sneak.berlin/go/keyfunc/internal/cli/options"
 	"sneak.berlin/go/keyfunc/internal/derive"
 	"sneak.berlin/go/keyfunc/internal/mnemonic"
 	"sneak.berlin/go/keyfunc/internal/sshkey"
 )
 // Command returns the ssh command and everything under it.
@@ -87,26 +84,6 @@ func write(cmd *cobra.Command, text string) error {
 	return nil
 }
 // childEnv is the tool's environment with the mnemonic variables taken
 // out, for the ssh and sftp children it starts. "ssh to" exists so the
 // private key never leaves the tool; the mnemonic, from either variable,
 // must not leave it either.
 func childEnv() []string {
 	environ := os.Environ()
 	kept := make([]string, 0, len(environ))
 	for _, entry := range environ {
 		name, _, _ := strings.Cut(entry, "=")
 		if name == mnemonic.Variable || name == mnemonic.CommandVariable {
 			continue
 		}
 		kept = append(kept, entry)
 	}
 	return kept
 }
 // addComment gives a command its comment flag.
 func addComment(cmd *cobra.Command) {
 	cmd.Flags().String(
@@ -7,10 +7,8 @@ import (
 	"os"
 	"os/exec"
 	"slices"
 	"syscall"
 	"github.com/spf13/cobra"
 	"sneak.berlin/go/keyfunc/internal/cli/signals"
 )
 // StatusError says the tool should end with the status ssh ended with.
@@ -43,14 +41,7 @@ func to() *cobra.Command {
 				return err
 			}
-			// From here until the agent is taken down, a signal
+			served, err := key.Serve(cmd.Context(), comment)
 			// cancels the context instead of ending the tool, so
 			// ssh ends and the socket and its directory are still
 			// removed.
 			ctx, stop := signals.Context(cmd.Context())
 			defer stop()
 			served, err := key.Serve(ctx, comment)
 			if err != nil {
 				return err
 			}
@@ -61,7 +52,7 @@ func to() *cobra.Command {
 				"-o", "IdentityAgent=" + served.Socket(),
 			}, args)
-			return connect(ctx, argv)
+			return connect(cmd.Context(), argv)
 		},
 	}
@@ -79,24 +70,17 @@ func to() *cobra.Command {
 func connect(ctx context.Context, argv []string) error {
 	//nolint:gosec // the arguments are the user's own, meant for ssh
 	command := exec.CommandContext(ctx, "ssh", argv...)
 	command.Env = childEnv()
 	command.Stdin = os.Stdin
 	command.Stdout = os.Stdout
 	command.Stderr = os.Stderr
 	// A cancelled context means a signal arrived. Send ssh a
 	// SIGTERM rather than the default kill, so it puts the terminal
 	// back the way it found it before it goes.
 	command.Cancel = func() error {
 		return command.Process.Signal(syscall.SIGTERM)
 	}
 	err := command.Run()
 	if err == nil {
 		return nil
 	}
-	if ended, ok := errors.AsType[*exec.ExitError](err); ok {
+	var ended *exec.ExitError
 	if errors.As(err, &ended) {
 		status := ended.ExitCode()
 		if status < 0 {
 			// A signal ended ssh, and a signal has no status of its
@@ -3,38 +3,18 @@ package cli_test
 import (
 	"bytes"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"slices"
 	"strconv"
 	"strings"
 	"syscall"
 	"testing"
 	"time"
 	"git.eeqj.de/sneak/keyfunc/internal/cli"
 	"git.eeqj.de/sneak/keyfunc/internal/cli/ssh"
 	"git.eeqj.de/sneak/keyfunc/internal/mnemonic"
 	"github.com/stretchr/testify/require"
 	"sneak.berlin/go/keyfunc/internal/cli"
 	"sneak.berlin/go/keyfunc/internal/cli/ssh"
 	"sneak.berlin/go/keyfunc/internal/mnemonic"
 )
 // runAsTool, set in the environment of a re-executed test binary, tells
 // TestMain to run the tool through Main rather than the suite, so the
 // signal tests can drive the real signal path in a process they can
 // send a signal to.
 const runAsTool = "KEYFUNC_TEST_RUN_AS_TOOL"
 // TestMain re-executes the test binary as the tool when runAsTool is
 // set, and otherwise runs the suite. The signal tests start the tool
 // this way, as a subprocess they can signal and watch end.
 func TestMain(m *testing.M) {
 	if os.Getenv(runAsTool) == "1" {
 		os.Exit(cli.Main())
 	}
 	os.Exit(m.Run())
 }
 // The modes the host is supposed to end up with, and the mode the
 // stand-ins need so that they can be run at all.
 const (
@@ -52,7 +32,7 @@ const (
 )
 // notADirectory is what a test puts where the .ssh directory belongs
-// to make a .ssh that is listed but cannot be entered.
+// to make a step of the write session fail.
 const notADirectory = "a file where the directory belongs\n"
 // missingIdentity is a path with no file at it, handed to sftp after
@@ -67,9 +47,6 @@ const (
 	keptIn    = "authorized_keys"
 )
 // remoteCommand is the command the "to" tests hand ssh after the host.
 const remoteCommand = "uptime"
 // The tool's own name, as it stands in the arguments a test hands to
 // Main, the ssh subcommand both commands the tests here drive live
 // under, and the one of those two these tests name most.
@@ -83,36 +60,22 @@ const (
 // an authorized_keys file.
 const keyLine = vectorZero + " keyfunc/ssh/0\n"
 // marker is a variable set beside the mnemonic ones and expected to
 // reach the stand-in, so a scrubbed environment is told apart from an
 // empty one.
 const marker = "KEYFUNC_TEST_MARKER"
 // installer is a stand-in for the system sftp for the install
 // command. It writes down the arguments and every command of the
-// batch it is given, echoes each command as sftp does, writes down its
+// batch it is given, echoes each command as sftp does, and carries
-// own environment when a test asks for it, and carries the commands out
+// the commands out against a directory standing in for the host's
-// against a directory standing in for the host's home directory, so that
+// home directory, so that what keyfunc sends can be watched doing its
-// what keyfunc sends can be watched doing its work. A command that
+// work. A command that begins with a dash may fail; any other failure
-// begins with a dash may fail; any other failure ends the session, as it
+// ends the session, as it does in sftp's own batch mode.
 // does in sftp's own batch mode.
 //
-// The listing and the two ways a get can fail are worded as the
+// The two ways a get can fail are worded as the OpenSSH client words
-// OpenSSH client words them, each naming the path the server expanded.
+// them, both naming the path the server expanded: a file that is not
-// A listing fails one way when .ssh is not there and another when it is
+// there, which is the one failure the tool reads as an empty file, and
-// there but shut to the user; the first is the only failure read as a
+// a file that is there and cannot be read, which is not. An -i naming
-// host with no file. A get fails one way for a file that is not there,
+// a file that is not here draws the warning ssh writes for it, which
 // which after a listing that came up empty is also read as no file, and
 // another for a file that is there and cannot be read, which is a
 // failure. A directory shut to the user is stood in for by mode 000,
 // which the listing reads off the mode itself so that the test does not
 // turn on the user it runs as, and one the user can enter but not write
 // to by mode 500, which the put reads off the same way. An -i naming a
 // file that is not here draws the warning ssh writes for it, which
 // carries the wording of a missing file into a session that goes on to
 // authenticate.
 const installer = `
 [ -n "$KEYFUNC_TEST_ENVIRONMENT" ] && env > "$KEYFUNC_TEST_ENVIRONMENT"
 previous=
 for argument in "$@"; do
 	printf '%s\n' "$argument" >> "$KEYFUNC_TEST_ARGUMENTS"
@@ -136,23 +99,6 @@ while IFS= read -r line; do
 	eval "set -- $line"
 	worked=yes
 	case "$1" in
 	ls)
 		dir=$2
 		[ "$dir" = -1 ] && dir=$3
 		if [ ! -e "$home/$dir" ]; then
 			worked=no
 			printf 'Can'\''t ls: "%s" not found\n' "$home/$dir" >&2
 		elif [ -d "$home/$dir" ] && [ "$(stat -c '%a' "$home/$dir")" = 0 ]; then
 			worked=no
 			printf 'remote readdir("%s/"): Permission denied\n' \
 				"$home/$dir" >&2
 		else
 			for entry in "$home/$dir"/*; do
 				[ -e "$entry" ] || continue
 				printf '%s/%s\n' "$dir" "$(basename "$entry")"
 			done
 		fi
 		;;
 	get)
 		if [ ! -e "$home/$2" ]; then
 			worked=no
@@ -162,13 +108,7 @@ while IFS= read -r line; do
 			printf 'remote open "%s": Permission denied\n' "$home/$2" >&2
 		fi
 		;;
-	put)
+	put) cp "$2" "$home/$3" 2>/dev/null || worked=no ;;
 		if [ "$(stat -c '%a' "$(dirname "$home/$3")")" = 500 ]; then
 			worked=no
 		else
 			cp "$2" "$home/$3" 2>/dev/null || worked=no
 		fi
 		;;
 	mkdir) mkdir "$home/$2" 2>/dev/null || worked=no ;;
 	chmod) chmod "$2" "$home/$3" 2>/dev/null || worked=no ;;
 	rename) mv "$home/$2" "$home/$3" 2>/dev/null || worked=no ;;
@@ -182,11 +122,9 @@ done
 // caller is a stand-in for the system ssh for the to command. It
 // writes down the arguments it was given, notes the agent socket if
-// there really is one at the path it was handed, writes down its own
+// there really is one at the path it was handed, and ends with the
-// environment when a test asks for it, and ends with the status the
+// status the test asked for.
 // test asked for.
 const caller = `
 [ -n "$KEYFUNC_TEST_ENVIRONMENT" ] && env > "$KEYFUNC_TEST_ENVIRONMENT"
 for argument in "$@"; do
 	printf '%s\n' "$argument" >> "$KEYFUNC_TEST_ARGUMENTS"
 done
@@ -197,28 +135,6 @@ fi
 exit "$KEYFUNC_TEST_STATUS"
 `
 // sleeper is a stand-in for the system ssh that notes the agent socket
 // and then blocks, so a test can cancel the context while it is running
 // and watch the tool take the agent down. The wait ends on its own only
 // as a backstop, well after the test has cancelled and looked.
 const sleeper = `
 socket=${2#IdentityAgent=}
 if [ -S "$socket" ]; then
 	printf '%s\n' "$socket" > "$KEYFUNC_TEST_SOCKET"
 fi
 sleep 5
 `
 // stalled is a stand-in for the system sftp that notes it has started
 // and then blocks, so a test can signal the tool while sftp is running
 // and watch it remove its working directory. The exec keeps the shell
 // from leaving a sleep behind that holds the output the tool reads sftp
 // through.
 const stalled = `
 touch "$KEYFUNC_TEST_STARTED"
 exec sleep 5
 `
 // pretended is where a stand-in writes down what it was asked to do.
 type pretended struct {
 	// home stands in for the home directory on the host.
@@ -260,8 +176,8 @@ func TestAKeyThatIsAlreadyThereIsLeftAlone(t *testing.T) {
 	require.Equal(t, "already present\n", install(t, host))
 	require.Equal(t, "somebody else\n"+keyLine, read(t, path))
-	// The read and nothing after it: the tool did not connect again.
+	// The fetch and nothing after it: the tool did not connect again.
-	require.Equal(t, 1, connections(t, pretend))
+	require.Len(t, recorded(t, pretend.batch), 1)
 }
 func TestAnEmptyFileGetsTheKeyAndNoBlankLineBeforeIt(t *testing.T) {
@@ -302,9 +218,7 @@ func TestTheFileIsUploadedBesideTheOldOneAndThenRenamedOverIt(t *testing.T) {
 		strings.HasPrefix(beside, ".ssh/authorized_keys.keyfunc-"),
 	)
-	// The listing fails on a host with no .ssh, so the get never runs;
+	require.True(t, strings.HasPrefix(sent[0], "get .ssh/authorized_keys "))
 	// the write session then makes the directory and puts the file.
 	require.Equal(t, "ls -1 .ssh", sent[0])
 	require.Equal(t, "-mkdir .ssh", sent[1])
 	require.Equal(t, "chmod 700 .ssh", sent[2])
 	require.Equal(t, "put", strings.Fields(sent[3])[0])
@@ -323,80 +237,12 @@ func TestAFileThatCannotBeReadIsNotWrittenOver(t *testing.T) {
 	require.Empty(t, printed)
 	require.Contains(t, said, "Permission denied")
-	// The read and nothing after it, and what was on the host is
+	// The fetch and nothing after it, and what was on the host is
 	// still what is on the host.
-	require.Equal(t, 1, connections(t, pretend))
+	require.Len(t, recorded(t, pretend.batch), 1)
 	require.DirExists(t, unreadable)
 }
 func TestAnUnreadableDirectoryIsNotWrittenInto(t *testing.T) {
 	t.Setenv(mnemonic.Variable, example())
 	pretend := pretendHost(t)
 	unlistable(t, pretend)
 	// The listing is refused, which is not the same as no directory, so
 	// the tool writes nothing rather than treat a directory it cannot
 	// enter as a host with no file.
 	printed, said, err := attempt(t, host)
 	require.Error(t, err)
 	require.Empty(t, printed)
 	require.Contains(t, said, "Permission denied")
 	// The read and nothing after it: no second connection wrote a key.
 	require.Equal(t, 1, connections(t, pretend))
 }
 func TestADirectoryThatCannotBeEnteredIsRefusedBeforeAnyUpload(t *testing.T) {
 	t.Setenv(mnemonic.Variable, example())
 	pretend := pretendHost(t)
 	// A file where .ssh belongs is listed and cannot be entered, which is
 	// how sftp sees a directory that can be read but not entered: the
 	// listing of .ssh comes up and the listing of .ssh/. finds nothing.
 	inTheWay := filepath.Join(pretend.home, keptUnder)
 	require.NoError(t,
 		os.WriteFile(inTheWay, []byte(notADirectory), fileMode),
 	)
 	printed, _, err := attempt(t, host)
 	require.ErrorIs(t, err, ssh.ErrCannotEnter)
 	require.Empty(t, printed)
 	// The read and nothing after it: no upload was tried, and what was
 	// on the host is still what is on the host.
 	require.Equal(t, 1, connections(t, pretend))
 	require.Equal(t, notADirectory, read(t, inTheWay))
 }
 func TestAnExistingDirectoryKeepsItsModeAndIsNotRemade(t *testing.T) {
 	t.Setenv(mnemonic.Variable, example())
 	pretend := pretendHost(t)
 	// A directory that is there but holds no file yet, made with a mode
 	// of its own so that a stray chmod would show.
 	const ownMode = 0o755
 	directory := filepath.Join(pretend.home, keptUnder)
 	require.NoError(t, os.Mkdir(directory, ownMode))
 	require.Equal(t, "added\n", install(t, host))
 	// The key is added and the directory keeps the mode it had: the
 	// write session neither made it nor set its mode.
 	require.Equal(t, keyLine, read(t, filepath.Join(directory, keptIn)))
 	kept, err := os.Stat(directory)
 	require.NoError(t, err)
 	require.Equal(t, os.FileMode(ownMode), kept.Mode().Perm())
 	sent := recorded(t, pretend.batch)
 	require.NotContains(t, sent, "-mkdir .ssh")
 	require.NotContains(t, sent, "chmod 700 .ssh")
 }
 func TestAWarningAboutAnotherFileIsNotTakenForTheOneAskedFor(t *testing.T) {
 	t.Setenv(mnemonic.Variable, example())
@@ -413,7 +259,7 @@ func TestAWarningAboutAnotherFileIsNotTakenForTheOneAskedFor(t *testing.T) {
 	require.Contains(t, said, "No such file or directory")
 	require.Contains(t, said, "Permission denied")
-	require.Equal(t, 1, connections(t, pretend))
+	require.Len(t, recorded(t, pretend.batch), 1)
 	require.DirExists(t, unreadable)
 	// The same run again, this way for the status it ends with.
@@ -433,30 +279,27 @@ func TestAFailedStepNamesTheUploadedFileAndChangesNothing(t *testing.T) {
 	pretend := pretendHost(t)
-	// A .ssh that can be listed and entered but not written to: the
+	// A file where the .ssh directory belongs: nothing is there to
-	// fetch finds no file in it, and then the put has nowhere to put
+	// fetch, and then the put has nowhere to put anything, so the
-	// anything, so the write session ends at the put.
+	// write session ends at the put.
-	const unwritable = 0o500
+	inTheWay := filepath.Join(pretend.home, keptUnder)
-
+	require.NoError(t,
-	directory := filepath.Join(pretend.home, keptUnder)
+		os.WriteFile(inTheWay, []byte(notADirectory), fileMode),
-	require.NoError(t, os.Mkdir(directory, unwritable))
+	)
 	printed, said, err := attempt(t, host)
 	require.Error(t, err)
 	require.Empty(t, printed)
 	require.Contains(t, said, "put failed")
-	// The put, after the three commands of the fetch, is the first and
+	// The put is the last command the session got to, and the file it
-	// last command the write session got to, and the file it was
+	// was uploading is the one the message names.
 	// uploading is the one the message names.
 	sent := recorded(t, pretend.batch)
 	require.Len(t, sent, 4)
 	require.Equal(t, "put", strings.Fields(sent[3])[0])
 	require.Contains(t, err.Error(), strings.Fields(sent[3])[2])
-	left, err := os.ReadDir(directory)
+	require.Equal(t, notADirectory, read(t, inTheWay))
 	require.NoError(t, err)
 	require.Empty(t, left)
 	// The same run again, this way for the status it ends with.
 	given := os.Args
@@ -500,7 +343,7 @@ func TestSSHIsPointedAtTheAgentAndItsStatusIsHandedOn(t *testing.T) {
 	arguments, noted := pretendCall(t)
-	_, err := execute(t, subcommand, "to", host, remoteCommand)
+	_, err := execute(t, subcommand, "to", host, "uptime")
 	var passed ssh.StatusError
@@ -509,7 +352,7 @@ func TestSSHIsPointedAtTheAgentAndItsStatusIsHandedOn(t *testing.T) {
 	given := recorded(t, arguments)
 	require.Equal(t, "-o", given[0])
-	require.Equal(t, []string{host, remoteCommand}, given[2:])
+	require.Equal(t, []string{host, "uptime"}, given[2:])
 	// The stand-in wrote the path down only because there really was
 	// a socket there while it ran.
@@ -527,180 +370,11 @@ func TestTheToolEndsWithTheStatusSSHEndedWith(t *testing.T) {
 	t.Cleanup(func() { os.Args = given })
-	os.Args = []string{tool, subcommand, "to", host, remoteCommand}
+	os.Args = []string{tool, subcommand, "to", host, "uptime"}
 	require.Equal(t, failingStatus, cli.Main())
 }
 func TestASignalTakesTheAgentDirectoryDown(t *testing.T) {
 	t.Setenv(mnemonic.Variable, example())
 	// The three signals the tool handles, checked one after another.
 	signals := []struct {
 		name   string
 		signal os.Signal
 	}{
 		{"SIGTERM", syscall.SIGTERM},
 		{"SIGINT", syscall.SIGINT},
 		{"SIGHUP", syscall.SIGHUP},
 	}
 	for _, ending := range signals {
 		signalEndsTheTool(t, ending.name, ending.signal)
 	}
 }
 // signalEndsTheTool runs the tool as a subprocess against a stand-in
 // ssh that blocks, waits until the agent is up and ssh is running
 // against it, sends the tool the signal, and requires the agent socket
 // and its directory to be gone once the tool has ended. The subprocess
 // goes through Main and the command's signal handling, so with that handling
 // removed the signal kills the tool outright, no deferred cleanup runs,
 // the directory is left behind, and the check fails.
 func signalEndsTheTool(t *testing.T, name string, signal os.Signal) {
 	t.Helper()
 	noted := filepath.Join(t.TempDir(), "socket")
 	t.Setenv("KEYFUNC_TEST_SOCKET", noted)
 	standIn(t, "ssh", sleeper)
 	//nolint:gosec // the binary is this test's own, re-run as the tool
 	command := exec.CommandContext(
 		t.Context(), os.Args[0], subcommand, "to", host, remoteCommand,
 	)
 	command.Env = append(os.Environ(), runAsTool+"=1")
 	require.NoError(t, command.Start())
 	// The stand-in notes the socket only once the agent is up and ssh
 	// is running against it, so this is where the signal lands.
 	socket := waitForSocket(t, noted)
 	require.NoError(t, command.Process.Signal(signal))
 	waitForTool(t, name, command)
 	// The signal ended the tool, and its deferred cleanup still ran:
 	// the agent socket and its directory are gone.
 	require.NoDirExists(t, filepath.Dir(socket), name)
 }
 // waitForTool waits for the subprocess to end, and fails the test if it
 // does not end in time.
 func waitForTool(t *testing.T, name string, command *exec.Cmd) {
 	t.Helper()
 	done := make(chan error, 1)
 	go func() { done <- command.Wait() }()
 	select {
 	case <-done:
 	case <-time.After(10 * time.Second):
 		t.Fatalf("the tool did not end after %s", name)
 	}
 }
 // waitForSocket waits for the stand-in to write down the agent socket
 // and gives back the path, which means the agent is up and ssh is
 // running against it.
 func waitForSocket(t *testing.T, noted string) string {
 	t.Helper()
 	var socket string
 	require.Eventually(t, func() bool {
 		content, err := os.ReadFile(noted) //nolint:gosec // test path
 		if err != nil {
 			return false
 		}
 		socket = strings.TrimSpace(string(content))
 		return socket != ""
 	}, 5*time.Second, 5*time.Millisecond)
 	return socket
 }
 func TestASignalTakesTheInstallWorkingDirectoryDown(t *testing.T) {
 	t.Setenv(mnemonic.Variable, example())
 	for _, ending := range []os.Signal{
 		syscall.SIGTERM, syscall.SIGINT, syscall.SIGHUP,
 	} {
 		signalEndsTheInstall(t, ending.String(), ending)
 	}
 }
 // signalEndsTheInstall runs "ssh install" as a subprocess against a
 // stand-in sftp that blocks, with a temporary directory of the test's
 // own, waits until sftp is running, sends the tool the signal, and
 // requires the working directory the tool made there to be gone once
 // the tool has ended.
 func signalEndsTheInstall(t *testing.T, name string, signal os.Signal) {
 	t.Helper()
 	temporary := t.TempDir()
 	started := filepath.Join(t.TempDir(), "started")
 	t.Setenv("KEYFUNC_TEST_STARTED", started)
 	standIn(t, "sftp", stalled)
 	//nolint:gosec // the binary is this test's own, re-run as the tool
 	command := exec.CommandContext(
 		t.Context(), os.Args[0], subcommand, installing, host,
 	)
 	command.Env = append(os.Environ(), runAsTool+"=1", "TMPDIR="+temporary)
 	require.NoError(t, command.Start())
 	// sftp is started only once the working directory has been made.
 	require.Eventually(t, func() bool {
 		_, err := os.Stat(started)
 		return err == nil
 	}, 5*time.Second, 5*time.Millisecond)
 	working, err := os.ReadDir(temporary)
 	require.NoError(t, err)
 	require.Len(t, working, 1, name)
 	require.NoError(t, command.Process.Signal(signal))
 	waitForTool(t, name, command)
 	left, err := os.ReadDir(temporary)
 	require.NoError(t, err)
 	require.Empty(t, left, name)
 }
 func TestTheMnemonicIsNotHandedToSFTP(t *testing.T) {
 	t.Setenv(mnemonic.CommandVariable, "echo "+example())
 	t.Setenv(mnemonic.Variable, example())
 	t.Setenv(marker, "reaches the stand-in")
 	pretendHost(t)
 	environment := recordEnvironment(t)
 	install(t, host)
 	mnemonicWithheld(t, read(t, environment))
 }
 func TestTheMnemonicIsNotHandedToSSH(t *testing.T) {
 	t.Setenv(mnemonic.CommandVariable, "echo "+example())
 	t.Setenv(mnemonic.Variable, example())
 	t.Setenv(marker, "reaches the stand-in")
 	pretendCall(t)
 	environment := recordEnvironment(t)
 	_, err := execute(t, subcommand, "to", host, remoteCommand)
 	var passed ssh.StatusError
 	require.ErrorAs(t, err, &passed)
 	mnemonicWithheld(t, read(t, environment))
 }
 // pretendHost puts the install stand-in on the path and gives back the
 // places it writes to.
 func pretendHost(t *testing.T) pretended {
@@ -781,38 +455,6 @@ func unfetchable(t *testing.T, pretend pretended) string {
 	return path
 }
 // unlistable puts a .ssh on the stand-in host that is there but shut to
 // the user, a directory of mode 000, and gives back its path. Its mode
 // is put back before the temporary directory is cleared so that it can
 // be.
 func unlistable(t *testing.T, pretend pretended) string {
 	t.Helper()
 	directory := filepath.Join(pretend.home, keptUnder)
 	require.NoError(t, os.Mkdir(directory, directoryMode))
 	require.NoError(t, os.Chmod(directory, 0))
 	t.Cleanup(func() { _ = os.Chmod(directory, directoryMode) })
 	return directory
 }
 // connections returns how many times the tool ran sftp, counted from
 // the -b that opens each session's arguments.
 func connections(t *testing.T, pretend pretended) int {
 	t.Helper()
 	count := 0
 	for _, argument := range recorded(t, pretend.arguments) {
 		if argument == "-b" {
 			count++
 		}
 	}
 	return count
 }
 // pretendCall puts the to stand-in on the path and gives back the file
 // the arguments are written down in and the file the agent socket is
 // noted in.
@@ -849,28 +491,6 @@ func standIn(t *testing.T, name, body string) {
 	)
 }
 // recordEnvironment asks the stand-in to write its environment down and
 // gives back the file it writes it to.
 func recordEnvironment(t *testing.T) string {
 	t.Helper()
 	path := filepath.Join(t.TempDir(), "environment")
 	t.Setenv("KEYFUNC_TEST_ENVIRONMENT", path)
 	return path
 }
 // mnemonicWithheld requires that neither mnemonic variable reached the
 // stand-in and that the marker set beside them did, so an empty
 // environment does not pass for a scrubbed one.
 func mnemonicWithheld(t *testing.T, environment string) {
 	t.Helper()
 	require.NotContains(t, environment, mnemonic.Variable+"=")
 	require.NotContains(t, environment, mnemonic.CommandVariable+"=")
 	require.Contains(t, environment, marker+"=")
 }
 // read returns what is in a file.
 func read(t *testing.T, path string) string {
 	t.Helper()
@@ -1,37 +0,0 @@
 package cli
 import (
 	"runtime/debug"
 	"testing"
 	"github.com/stretchr/testify/require"
 )
 func TestResolveVersion(t *testing.T) {
 	t.Parallel()
 	release := &debug.BuildInfo{Main: debug.Module{Version: "v1.2.3"}}
 	local := &debug.BuildInfo{Main: debug.Module{Version: "(devel)"}}
 	empty := &debug.BuildInfo{}
 	t.Run("stamped value wins over build info", func(t *testing.T) {
 		t.Parallel()
 		require.Equal(t, "v0.1.0", resolveVersion("v0.1.0", release))
 	})
 	t.Run("go install reports the module version", func(t *testing.T) {
 		t.Parallel()
 		require.Equal(t, "v1.2.3", resolveVersion(devVersion, release))
 	})
 	t.Run("a local build stays dev", func(t *testing.T) {
 		t.Parallel()
 		require.Equal(t, devVersion, resolveVersion(devVersion, local))
 	})
 	t.Run("no version anywhere stays dev", func(t *testing.T) {
 		t.Parallel()
 		require.Equal(t, devVersion, resolveVersion(devVersion, empty))
 		require.Equal(t, devVersion, resolveVersion(devVersion, nil))
 	})
 }
@@ -5,8 +5,8 @@ import (
 	"strings"
 	"testing"
 	"git.eeqj.de/sneak/keyfunc/internal/derive"
 	"github.com/stretchr/testify/require"
 	"sneak.berlin/go/keyfunc/internal/derive"
 )
 // application is the number the SSH key type uses.
@@ -104,11 +104,10 @@ func ask() (string, error) {
 	return checked(string(typed))
 }
-// checked joins the words with single spaces, whatever whitespace
+// checked drops the surrounding whitespace and refuses a mnemonic that
-// separated them, since the seed is computed over the string itself,
+// does not pass the BIP-39 checksum.
 // and refuses a mnemonic that does not pass the BIP-39 checksum.
 func checked(words string) (string, error) {
-	words = strings.Join(strings.Fields(words), " ")
+	words = strings.TrimSpace(words)
 	if !bip39.IsMnemonicValid(words) {
 		return "", ErrChecksum
@@ -4,8 +4,8 @@ import (
 	"strings"
 	"testing"
 	"git.eeqj.de/sneak/keyfunc/internal/mnemonic"
 	"github.com/stretchr/testify/require"
 	"sneak.berlin/go/keyfunc/internal/mnemonic"
 )
 // Two more mnemonics that pass the checksum, so a test can tell which
@@ -7,11 +7,11 @@ import (
 	"strings"
 	"testing"
 	"git.eeqj.de/sneak/keyfunc/internal/derive"
 	"git.eeqj.de/sneak/keyfunc/internal/sshkey"
 	"github.com/stretchr/testify/require"
 	"golang.org/x/crypto/ssh"
 	"golang.org/x/crypto/ssh/agent"
 	"sneak.berlin/go/keyfunc/internal/derive"
 	"sneak.berlin/go/keyfunc/internal/sshkey"
 )
 // agentDirectoryMode is what the directory holding the agent socket
@@ -1,5 +0,0 @@
 {
  "devDependencies": {
    "prettier": "3.8.1"
  }
 }
@@ -3,35 +3,13 @@
 # repo. Idempotent: every install is guarded by a check, so tools that
 # are already there are left alone. Base tooling comes from nix, apt,
 # brew, or apk, detected in that order, and nothing is assumed to be
-# present. Go is installed at the version the Dockerfile's Go image
+# present. The linter is not installed here: it only ever runs inside
-# carries, from the official release archive, into ~/.local/go. Node is
+# the image built from Dockerfile.lint, so Docker is what is needed for
-# used directly if installed; otherwise it is installed at a pinned
+# it, and that is checked for rather than installed.
 # version via nvm (installing nvm itself first, from a hash-verified
 # release archive, never curl | sh). The linter is not installed here:
 # linting and testing run only as phases of the Dockerfile, so Docker is
 # what is needed for them, and that is checked for rather than
 # installed.
 set -eu
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 # Must match the Go in the Dockerfile's golang image; the sha256 of each
 # archive is in install_go.
 GO_VERSION="1.26.8"
 # This script cannot change its caller's PATH, so script/fmt,
 # script/fmt-check, script/precommit and the Makefile put this directory
 # first on their own PATH, as is done here.
 GO_DIR="$HOME/.local/go"
 PATH="$GO_DIR/bin:$PATH"
 # Pinned versions, 2026-07-06
 NODE_VERSION="22.17.0"
 NVM_VERSION="0.40.3"
 # sha256 of https://github.com/nvm-sh/nvm/archive/refs/tags/v0.40.3.tar.gz
 NVM_SHA256="5f4d6aaa04a177dc93c985e31dbc411ab6b8c6e1e21d8015dbc1372625fcd1d0"
 YARN_VERSION="1.22.22"
 PKGMGR=""
 SUDO=""
@@ -54,9 +32,6 @@ detect_pkgmgr() {
        if [ "$(id -u)" != "0" ]; then
            SUDO="sudo"
        fi
        # This runs once, before the first install: a fresh host or
        # runner image has no package lists yet.
        $SUDO apt-get update
    fi
 }
@@ -75,139 +50,17 @@ missing() {
    ! command -v "$1" >/dev/null 2>&1
 }
 # verify_sha256 <file> <expected-hash>
 verify_sha256() {
    if command -v sha256sum >/dev/null 2>&1; then
        actual="$(sha256sum "$1" | cut -d' ' -f1)"
    else
        actual="$(shasum -a 256 "$1" | cut -d' ' -f1)"
    fi
    if [ "$actual" != "$2" ]; then
        echo "bootstrap: sha256 mismatch for $1" >&2
        echo "  expected: $2" >&2
        echo "  actual:   $actual" >&2
        exit 1
    fi
 }
 # True when the go first on PATH reports exactly GO_VERSION. No go, a go
 # that fails, or any other output is a mismatch.
 go_version_matches() {
    out="$(go version 2>/dev/null)" || return 1
    case "$out" in
        "go version go$GO_VERSION "*) return 0 ;;
        *) return 1 ;;
    esac
 }
 install_go() {
    # sha256 of the go1.26.8 archives at https://go.dev/dl/, 2026-10-04
    case "$(uname -s)-$(uname -m)" in
        Linux-x86_64)
            platform="linux-amd64"
            sha256="d0f743b33e8d8945e6b1f432edd15785c70507121d6e2a723b21285eddf8b57b"
            ;;
        Linux-aarch64)
            platform="linux-arm64"
            sha256="211ffced9dcb9633a55eac6364816ec0ddd951389a740e88fa8b3337971bdda0"
            ;;
        Darwin-x86_64)
            platform="darwin-amd64"
            sha256="186be014105aa6542b767d2c6ed5cca10a0214bdff809ef1724022a8c7894150"
            ;;
        Darwin-arm64)
            platform="darwin-arm64"
            sha256="a012b25b571bd0138a03dcd25375ceba866fe5ca822f426d2c66a4de56fd3f4b"
            ;;
        *)
            echo "bootstrap: no Go archive pinned for $(uname -s) $(uname -m)" >&2
            exit 1
            ;;
    esac
    if missing curl; then pkg_install curl curl curl curl; fi
    tmp="$(mktemp -d)"
    curl -fsSL -o "$tmp/go.tar.gz" \
        "https://go.dev/dl/go${GO_VERSION}.${platform}.tar.gz"
    verify_sha256 "$tmp/go.tar.gz" "$sha256"
    # An archive unpacked over an older Go leaves a broken tree.
    rm -rf "$GO_DIR"
    mkdir -p "$GO_DIR"
    tar -xzf "$tmp/go.tar.gz" -C "$GO_DIR" --strip-components=1
    rm -rf "$tmp"
 }
 # nvm is a bash script; run a command in a bash with nvm loaded
 nvm_sh() {
    bash -c ". \"\$HOME/.nvm/nvm.sh\" && $*"
 }
 ensure_nvm() {
    [ -s "$HOME/.nvm/nvm.sh" ] && return 0
    # nvm prerequisites; nvm itself requires bash
    if missing bash; then pkg_install bash bash bash bash; fi
    if missing curl; then pkg_install curl curl curl curl; fi
    if missing git; then pkg_install git git git git; fi
    tmp="$(mktemp -d)"
    curl -fsSL -o "$tmp/nvm.tar.gz" \
        "https://github.com/nvm-sh/nvm/archive/refs/tags/v${NVM_VERSION}.tar.gz"
    verify_sha256 "$tmp/nvm.tar.gz" "$NVM_SHA256"
    mkdir -p "$HOME/.nvm"
    tar -xzf "$tmp/nvm.tar.gz" -C "$HOME/.nvm" --strip-components=1
    rm -rf "$tmp"
 }
 ensure_node() {
    if ! missing node; then return 0; fi
    ensure_nvm
    nvm_sh "nvm install $NODE_VERSION"
 }
 ensure_yarn() {
    if ! missing yarn; then return 0; fi
    if ! missing corepack; then
        corepack enable
        corepack prepare "yarn@$YARN_VERSION" --activate
    elif [ -s "$HOME/.nvm/nvm.sh" ]; then
        nvm_sh "nvm use $NODE_VERSION >/dev/null && corepack enable && \
            corepack prepare yarn@$YARN_VERSION --activate"
    else
        npm install -g "yarn@$YARN_VERSION"
    fi
 }
 install_js_deps() {
    if missing yarn && [ -s "$HOME/.nvm/nvm.sh" ]; then
        nvm_sh "nvm use $NODE_VERSION >/dev/null && cd \"$ROOT\" && \
            yarn install --frozen-lockfile"
    else
        yarn install --frozen-lockfile
    fi
 }
 main() {
    cd "$ROOT"
    if missing git; then pkg_install git git git git; fi
    if missing make; then pkg_install gnumake make make make; fi
-
+    if missing go; then pkg_install go golang go go; fi
    if ! go_version_matches; then
        install_go
        hash -r
        if ! go_version_matches; then
            echo "bootstrap: $(command -v go) is not go$GO_VERSION after installing it" >&2
            exit 1
        fi
    fi
    go version
    go mod download
    ensure_node
    ensure_yarn
    install_js_deps
    if missing docker; then
-        echo "bootstrap: docker is not installed; make lint and make test need it" >&2
+        echo "bootstrap: docker is not installed; make lint needs it" >&2
    fi
    echo "bootstrap complete"
@@ -1,10 +1,8 @@
 #!/bin/sh
-# script/cibuild: run the CI build. It bootstraps first: a CI runner
+# script/cibuild: run the CI build. The linter needs an image of its
-# checks out and runs this and nothing else, and script/fmt-check runs
+# own, so it runs first; the Dockerfile then runs the formatting check,
-# the formatter on the host, which a pristine checkout cannot do.
+# the tests and the build, so a green run here means make check is
-# --no-cache for the same reason as script/docker: the gate phases the
+# green.
 # final stage depends on are RUN steps, and a cached one is a check that
 # did not run.
 set -eu
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
@@ -12,17 +10,8 @@ ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 main() {
    cd "$ROOT"
-    "$SCRIPT_DIR/bootstrap"
+    "$SCRIPT_DIR/lint"
-    "$SCRIPT_DIR/check"
+    docker build .
    # Own line: a failing command substitution inside an argument does
    # not trip `set -e`, so the inline form degrades silently to an
    # empty constant. The VERSION build argument takes precedence over
    # the version a build stage derives from the .git in the context.
    version="$(git describe --tags --always --dirty 2>/dev/null || true)"
    [ -n "$version" ] || version="unknown"
    docker build --no-cache \
        --build-arg VERSION="$version" \
        -t "$("$SCRIPT_DIR/projectname")" .
 }
 main "$@"
@@ -1,8 +1,6 @@
 #!/bin/sh
 # script/docker: build the Docker image tagged with the project name.
 # Identical in all repos; the tag comes from script/projectname.
 # --no-cache because the gate phases the final stage depends on are RUN
 # steps, and a cached one is a check that did not run.
 set -eu
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
@@ -10,15 +8,7 @@ ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 main() {
    cd "$ROOT"
-    # Own line: a failing command substitution inside an argument does
+    docker build -t "$("$SCRIPT_DIR/projectname")" .
    # not trip `set -e`, so the inline form degrades silently to an
    # empty constant. The VERSION build argument takes precedence over
    # the version a build stage derives from the .git in the context.
    version="$(git describe --tags --always --dirty 2>/dev/null || true)"
    [ -n "$version" ] || version="unknown"
    docker build --no-cache \
        --build-arg VERSION="$version" \
        -t "$("$SCRIPT_DIR/projectname")" .
 }
 main "$@"
@@ -1,36 +1,12 @@
 #!/bin/sh
-# script/fmt: format all files (writes): the Go source with go fmt, then
+# script/fmt: format all files (writes).
 # the Markdown files with prettier.
 set -eu
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 # Where script/bootstrap installs Go; it cannot put it on our PATH.
 PATH="$HOME/.local/go/bin:$PATH"
 # Must match the pin in script/bootstrap.
 NODE_VERSION="22.17.0"
 # script/bootstrap installs node and yarn under nvm and leaves neither
 # on the PATH of the shell that called it, so resolve the pinned
 # toolchain here the way bootstrap's own install step does. nvm is a
 # bash script, hence the subshell.
 run_yarn() {
    if command -v yarn >/dev/null 2>&1; then
        exec yarn "$@"
    fi
    if [ ! -s "$HOME/.nvm/nvm.sh" ]; then
        echo "fmt: no yarn; run script/bootstrap first" >&2
        exit 1
    fi
    exec bash -c '. "$HOME/.nvm/nvm.sh" && nvm use "$1" >/dev/null &&
        shift && exec yarn "$@"' bash "$NODE_VERSION" "$@"
 }
 main() {
    cd "$ROOT"
    go fmt ./...
    run_yarn run prettier --write '**/*.md' --tab-width 4 --prose-wrap always
 }
 main "$@"
@@ -5,28 +5,6 @@ set -eu
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 # Where script/bootstrap installs Go; it cannot put it on our PATH.
 PATH="$HOME/.local/go/bin:$PATH"
 # Must match the pin in script/bootstrap.
 NODE_VERSION="22.17.0"
 # script/bootstrap installs node and yarn under nvm and leaves neither
 # on the PATH of the shell that called it, so resolve the pinned
 # toolchain here the way bootstrap's own install step does. nvm is a
 # bash script, hence the subshell.
 run_yarn() {
    if command -v yarn >/dev/null 2>&1; then
        exec yarn "$@"
    fi
    if [ ! -s "$HOME/.nvm/nvm.sh" ]; then
        echo "fmt-check: no yarn; run script/bootstrap first" >&2
        exit 1
    fi
    exec bash -c '. "$HOME/.nvm/nvm.sh" && nvm use "$1" >/dev/null &&
        shift && exec yarn "$@"' bash "$NODE_VERSION" "$@"
 }
 main() {
    cd "$ROOT"
    if [ -n "$(gofmt -l .)" ]; then
@@ -34,7 +12,6 @@ main() {
        gofmt -l .
        exit 1
    fi
    run_yarn run prettier --check '**/*.md' --tab-width 4 --prose-wrap always
 }
 main "$@"
@@ -1,13 +1,9 @@
 #!/bin/sh
-# script/lint: run the linter. Linting is a phase of the Dockerfile and
+# script/lint: run the linter. Linting only ever happens inside the
-# this builds that phase alone; the linter is never installed or run on
+# image built from Dockerfile.lint, which pins the linter by hash, so
-# a developer host, where a shared result cache and a host-global lock
+# the answer is the same on every machine and in CI. The linter runs as
-# make its answer untrustworthy.
+# a build step of that image, so a complaint fails the build and no
-#
+# container is left behind.
 # The phase is not the last stage in the file, so it is built only when
 # --target names it. --no-cache because a cached lint layer is a lint
 # that did not run. The tag makes each build replace the previous image
 # instead of leaving a dangling one behind.
 set -eu
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
@@ -15,8 +11,7 @@ ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 main() {
    cd "$ROOT"
-    docker build --no-cache \
+    docker build --progress=plain -f Dockerfile.lint \
        --target lint \
        -t "$("$SCRIPT_DIR/projectname")-lint" .
 }
@@ -7,9 +7,6 @@ set -eu
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
 ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 # Where script/bootstrap installs Go; it cannot put it on our PATH.
 PATH="$HOME/.local/go/bin:$PATH"
 main() {
    cd "$ROOT"
    go mod tidy
@@ -1,19 +1,13 @@
 #!/bin/sh
-# script/test: run the test suite. Testing is a phase of the Dockerfile
+# script/test: run the test suite (vet first, verbose rerun on failure).
 # and this builds that phase alone, on the same terms as script/lint:
 # --target because a phase that is not the last stage is built only when
 # named, --no-cache because a cached test layer is a test that did not
 # run, and a tag so each build replaces the previous image.
 set -eu
-SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 main() {
    cd "$ROOT"
-    docker build --no-cache \
+    go vet ./...
-        --target test \
+    go test -timeout 90s ./... || go test -timeout 90s -v ./...
        -t "$("$SCRIPT_DIR/projectname")-test" .
 }
 main "$@"
@@ -1,8 +0,0 @@
 # THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
 # yarn lockfile v1
 prettier@3.8.1:
  version "3.8.1"
  resolved "https://registry.yarnpkg.com/prettier/-/prettier-3.8.1.tgz#edf48977cf991558f4fcbd8a3ba6015ba2a3a173"
  integrity sha512-UOnG6LftzbdaHZcKoPFtOcCKztrQ57WkHDeRD9t/PTQtmT0NHSeWWepj6pS0z/N7+08BHFDQVUrfmfMRcZwbMg==
`@@ -1,4 +1,4 @@`
	`module sneak.berlin/go/keyfunc`	`module git.eeqj.de/sneak/keyfunc`

	`go 1.26.0`	`go 1.26.0`