Say max_retries is the total attempt count, not a retry count (closes #316)

The delivery core makes max_retries attempts in total: a fresh delivery
starts at attempt one and gives up once the attempt number reaches
max_retries, so 3 is three attempts, not four, and 0 is special-cased to
a single fire-and-forget attempt with no retries and no circuit breaker.
The create and edit target forms called it "Max retries" with no total,
and the README data-model row called it "maximum retry attempts", so an
operator wanting "try, then retry twice" would enter the wrong number.

Both forms and the README rows now state the number is the total number
of delivery attempts, with the 0 case spelled out. The delivery
arithmetic is unchanged. A UI copy test renders both forms and pins the
shared wording so it cannot drift back to a retry count.

Model: opus-4-8

README.md

@@ -7,6 +7,13 @@ services, durably stores them, and delivers them to configured targets
 with retry support, logging, and observability. Category: infrastructure
 / web service. License: MIT.
 
+Each entrypoint is a version 4 UUID served at `/webhook/{uuid}`, and
+that UUID is the entrypoint's only credential. webhooker does not use
+shared secrets, HMAC signatures or token headers on the receiver, and
+will not add them — read
+[The entrypoint URL is the authentication secret](#the-entrypoint-url-is-the-authentication-secret)
+before deploying one.
+
 ## Getting Started
 
 ### Prerequisites
@@ -1149,14 +1156,38 @@ backups at rest and restrict who can read them.
 
 ## The entrypoint URL is the authentication secret
 
-The receiver verifies nothing about an inbound request. The UUID in an
-entrypoint's URL is its credential: anyone who holds that URL can
-submit events to it, and the receiver checks nothing else about the
-sender. Treat an entrypoint URL the way you would treat an API token.
+**The entrypoint UUID is the credential, and it is the only one.**
+webhooker mints a version 4 UUID per entrypoint and serves it at
+`/webhook/{uuid}`. Possession of that URL is the authentication:
+anyone who holds it can submit events to the entrypoint, and the
+receiver verifies nothing else about the sender.
 
-There is no way to rotate the UUID in place. To retire one, delete the
-entrypoint (or deactivate it, which answers `410`) and create a new
-one, then point the sender at the new URL.
+There is no shared secret, no HMAC signature, no bearer token and no
+second factor on the receiver, and none will be added. This was
+considered and rejected; the implementation that existed was removed
+in [PR #279](https://git.eeqj.de/sneak/webhooker/pulls/279), closing
+[issue #67](https://git.eeqj.de/sneak/webhooker/issues/67) and
+[issue #241](https://git.eeqj.de/sneak/webhooker/issues/241). A
+proposal to reintroduce any of them — including as "defence in depth"
+alongside the UUID — is answered by this section. Inbound signature
+headers a sender sends anyway (`X-Hub-Signature` and its
+per-provider equivalents) are stored and forwarded as ordinary
+headers; nothing checks them.
+
+What that means for an operator:
+
+- **The URL is a capability, so treat it as a secret.** Keep it out of
+  logs, ticket bodies, chat messages and screenshots. Anyone who reads
+  it anywhere can post events as that sender.
+- **Rotating means minting a new entrypoint, not changing a key.**
+  There is no way to rotate the UUID in place. To retire one, delete
+  the entrypoint (or deactivate it, which answers `410`) and create a
+  new one, then point the sender at the new URL.
+- **A sender that cannot be given a secret URL is a constraint on that
+  integration, not a reason to change this.** If a service only
+  supports signed payloads to a well-known URL, raise it as its own
+  problem — pick a different integration path, or accept that it
+  cannot be used. It is not grounds to reintroduce shared secrets.
 
 ## Entrypoints
 
@@ -1476,7 +1507,7 @@ events should be forwarded.
 | `type`           | TargetType | One of: `http`, `slack`, `database`, `log` |
 | `active`         | boolean    | Whether deliveries are enabled (default: true) |
 | `config`         | JSON text  | Type-specific configuration |
-| `max_retries`    | integer    | Maximum retry attempts for `http` and `slack` targets (0 = fire-and-forget, >0 = retries with backoff and a circuit breaker). Ignored by `database` and `log` targets |
+| `max_retries`    | integer    | Total delivery attempts for `http` and `slack` targets, not retries on top of the first: 0 is a single fire-and-forget attempt with no retries and no circuit breaker, and a value of N makes N attempts in all, with exponential backoff and a per-target circuit breaker. Ignored by `database` and `log` targets |
 | `max_queue_size` | integer    | Stored and shown on the target's detail view, but not enforced anywhere yet: nothing in the delivery engine consults it. Queue depth is set by the two fixed 10,000-entry channels |
 
 **Relations:** Belongs to Webhook. Has many Deliveries.
@@ -1484,12 +1515,12 @@ events should be forwarded.
 **Target types:**
 
 - **`http`** — Forward the event as an HTTP POST to a configured URL.
-  Behavior depends on `max_retries`: when `max_retries` is 0 (the
-  default), the target operates in fire-and-forget mode — a single
-  attempt with no retries and no circuit breaker. When `max_retries` is
-  greater than 0, failed deliveries are retried with exponential backoff
-  up to `max_retries` attempts, protected by a per-target circuit
-  breaker.
+  `max_retries` is the total number of delivery attempts, not retries on
+  top of the first: when `max_retries` is 0 (the default), the target
+  operates in fire-and-forget mode, a single attempt with no retries and
+  no circuit breaker; a value of N makes up to N attempts in all,
+  retrying failed deliveries with exponential backoff and protecting them
+  with a per-target circuit breaker.
 - **`slack`** — Post the event as a formatted message to a
   Slack-compatible incoming webhook URL (`webhookUrl` in `config`). It
   is built on the same HTTP core as `http` and honours `max_retries`
@@ -2867,6 +2898,10 @@ check, see [The login endpoint](#the-login-endpoint).
 
 ### Authentication
 
+- **Webhook receiver:** the entrypoint UUID in the URL, and nothing
+  else. No shared secret, no HMAC signature, no token header, and none
+  will be added — see
+  [The entrypoint URL is the authentication secret](#the-entrypoint-url-is-the-authentication-secret).
 - **Web UI:** Cookie-based sessions using gorilla/sessions with
   encrypted cookies. Sessions are configured with HttpOnly, SameSite
   Lax, and Secure whenever the request is on TLS — the flag follows the
@@ -2906,7 +2941,8 @@ check, see [The login endpoint](#the-login-endpoint).
   mode
 - **The entrypoint URL is the receiver's only credential.** Nothing
   about an inbound request is verified; possession of the UUID
-  authorises submission (see
+  authorises submission, and no shared secret or signature check will
+  be added alongside it (see
   [The entrypoint URL is the authentication secret](#the-entrypoint-url-is-the-authentication-secret))
 - **SSRF prevention** for HTTP delivery targets: private/reserved IP
   ranges (RFC 1918, loopback, link-local, cloud metadata) are blocked

internal/delivery/redirect_test.go

@@ -170,7 +170,8 @@ func TestDelivery_CrossOriginRedirectDropsOriginScopedHeaders(
 // Stripping must not fire within the configured origin, or every
 // destination that redirects its own path would lose its
 // credential and start answering 401 — and would lose the inbound
-// signature the receiver verifies.
+// signature header the target endpoint verifies. webhooker's own
+// receiver verifies no signature; it only forwards the header.
 func TestDelivery_SameOriginRedirectKeepsOriginScopedHeaders(
 	t *testing.T,
 ) {

internal/handlers/ui_copy_test.go

@@ -300,3 +300,80 @@ func TestEntrypointCopyButtonIsProgressiveEnhancement(t *testing.T) {
 		"the page must render to completion, not abort partway",
 	)
 }
+
+// maxRetriesHelp is the wording both target forms must carry. The
+// delivery core makes max_retries attempts in total, not that many
+// retries on top of a first try (a fresh delivery starts at attempt 1
+// and target_http gives up once the attempt number reaches
+// max_retries), and 0 is special-cased to a single fire-and-forget
+// attempt with no circuit breaker.
+const maxRetriesHelp = "This is the total number of delivery attempts, " +
+	"not retries on top of the first: a value of 3 makes three attempts " +
+	"in all. 0 means a single attempt with no retries and no circuit " +
+	"breaker."
+
+// TestTargetFormMaxRetriesCopyMatchesBehaviour pins the max_retries
+// help text on both the create form (the add-target form on the webhook
+// detail page) and the edit form, so the copy cannot drift back to
+// calling the number a retry count.
+func TestTargetFormMaxRetriesCopyMatchesBehaviour(t *testing.T) {
+	t.Parallel()
+
+	var h *handlers.Handlers
+
+	var sess *session.Session
+
+	app := newTestApp(t, &h, &sess)
+	app.RequireStart()
+
+	t.Cleanup(app.RequireStop)
+
+	webhook := &database.Webhook{Name: "wh", RetentionDays: 14}
+	webhook.ID = testWebhookID
+
+	entrypoint := database.Entrypoint{Path: "abc123"}
+	entrypoint.ID = "ep-1"
+
+	createBody := renderPage(
+		t, h, sess, "source_detail.html", map[string]any{
+			dataKeyWebhook: webhook,
+			"Entrypoints": handlers.NewEntrypointViews(
+				[]database.Entrypoint{entrypoint},
+			),
+			"Targets": delivery.NewTargetViews(nil),
+			"Events":  []database.Event{},
+			"BaseURL": "https://hooks.example.com",
+		},
+	)
+
+	assert.Contains(
+		t, createBody, maxRetriesHelp,
+		"the add-target form must explain max_retries as total attempts",
+	)
+
+	// A slack target exercises the same max_retries field while needing
+	// only Config.URL from the edit template, so the test data stays
+	// minimal. The Target key mirrors the field names the template reads
+	// off the handler's view value.
+	editBody := renderPage(
+		t, h, sess, "target_edit.html", map[string]any{
+			dataKeyWebhook: webhook,
+			"Target": map[string]any{
+				"ID":         "tg-1",
+				"Name":       "t",
+				"Type":       "slack",
+				"Active":     true,
+				"MaxRetries": 3,
+				"Config": map[string]any{
+					"URL": "https://hooks.slack.com/services/x",
+				},
+			},
+			dataKeyError: "",
+		},
+	)
+
+	assert.Contains(
+		t, editBody, maxRetriesHelp,
+		"the target edit form must explain max_retries as total attempts",
+	)
+}

templates/source_detail.html

@@ -120,9 +120,12 @@
                         <label class="text-sm text-gray-700">Timeout (seconds, blank = default):</label>
                         <input type="number" name="timeout" min="0" max="300" :disabled="targetType !== 'http'" class="input text-sm w-24">
                     </div>
-                    <div x-show="targetType === 'http'" class="flex gap-2 items-center">
-                        <label class="text-sm text-gray-700">Max retries (0 = fire-and-forget):</label>
-                        <input type="number" name="max_retries" value="0" min="0" max="20" class="input text-sm w-24">
+                    <div x-show="targetType === 'http'">
+                        <div class="flex gap-2 items-center">
+                            <label class="text-sm text-gray-700">Max retries:</label>
+                            <input type="number" name="max_retries" value="0" min="0" max="20" class="input text-sm w-24">
+                        </div>
+                        <p class="text-xs text-gray-500 mt-1">This is the total number of delivery attempts, not retries on top of the first: a value of 3 makes three attempts in all. 0 means a single attempt with no retries and no circuit breaker.</p>
                     </div>
                     <div x-show="targetType === 'slack'">
                         <input type="url" name="url" placeholder="https://hooks.slack.com/services/..." :disabled="targetType !== 'slack'" class="input text-sm">

templates/target_edit.html

@@ -69,7 +69,7 @@
             <div class="form-group">
                 <label for="max_retries" class="label">Max retries</label>
                 <input type="number" id="max_retries" name="max_retries" value="{{.Target.MaxRetries}}" min="0" max="20" class="input">
-                <p class="text-xs text-gray-500 mt-1">0 is fire-and-forget: one attempt, no circuit breaker.</p>
+                <p class="text-xs text-gray-500 mt-1">This is the total number of delivery attempts, not retries on top of the first: a value of 3 makes three attempts in all. 0 means a single attempt with no retries and no circuit breaker.</p>
             </div>
             {{end}}