docs: name every approval-screen amount string, fix stale zero claim (closes #369)

The README's amount-display section claimed a genuine zero always renders
`0.0000`. That is corrected and scoped: it holds for the ERC-20 amount and for
the swap's `Amount` line on a literal-zero `amountIn` in a V2/V3 exact-in swap
or a zero `WRAP_ETH`. Only two zeros are stated in words before the floor — the
swap's `Min. received` (any zero minimum) and its V4 exact-in `Amount` (an
`amountIn` of zero, V4's open delta).

A new list names every string an amount slot can show: a formatted quantity,
`Unlimited`, `All available (V4 open delta)`, `None (no minimum guaranteed)`,
base units with decimals unknown, and `Unknown (not named in the calldata)`. It
also records that a zero `minBalance` on a `BALANCE_CHECK_ERC20` step now reads
the no-minimum wording where it once read `0.0000`. Each claim checked against
the tree. Docs only.

Model: opus-4-8

README.md

@@ -882,9 +882,18 @@ On those screens, when the truncated string would contain no digit from 1 to 9
 and the value does, the amount is extended to its first significant digit
 instead: `0.000000000000000001 DAI`, not `0.0000 DAI`. The test is on the whole
 truncated string, integer part included, so `1.00005` still shows as `1.0000` —
-the exception only fires where the entire displayed figure would read as zero. A
-genuine zero still renders `0.0000`, and truncation stays truncation: `0.99999`
-shows as `0.9999`, never rounded up.
+the exception only fires where the entire displayed figure would read as zero.
+Truncation stays truncation: `0.99999` shows as `0.9999`, never rounded up. A
+genuine zero reaching this rule renders `0.0000`. The ERC-20
+`approve`/`transfer` amount does exactly that, and so does the swap's `Amount`
+line for a literal-zero `amountIn` on a V2 or V3 exact-in swap, or a zero
+`WRAP_ETH` (`0.0000 ETH`). Only two zeros are stated in words before the floor:
+the swap's `Min. received` line reads `None (no minimum guaranteed)` for any
+zero minimum, and its `Amount` line reads `All available (V4 open delta)` for a
+V4 exact-in `amountIn` of zero, which V4 treats as the whole open credit rather
+than a quantity. So the guarantee that a zero is never shown as `0.0000` covers
+the `Min. received` line and the V4 exact-in `Amount`; a V2/V3 or `WRAP_ETH`
+`Amount` still renders it (see the list of amount-slot strings below).
 
 The rule and its exception live in `src/shared/amountDisplay.js` as
 `truncateAmount()` and `truncateAmountNeverZero()`. Everything the approval and
@@ -936,6 +945,38 @@ and compare against. Reading the stored field directly instead answers `null`
 for a bundled or tracked token the explorer merely omitted, which is not a
 refusal the wallet has any reason to make.
 
+**Every string an amount slot can show:** taken together, the exceptions above
+mean an amount line on the dApp approval screen (and the wait/success/error
+screens that carry a figure forward) shows one of a fixed set of strings, not
+always a number:
+
+- A formatted quantity, e.g. `17.1900 USDT`: the token's scale is known and the
+  figure is at or above the floor, or below it and extended to its first
+  significant digit. This is `truncateAmountNeverZero()`
+  (`src/shared/amountDisplay.js`).
+- `Unlimited`: an unbounded allowance or permit, which needs no scale to
+  describe — a `uint256`-max ERC-20 `approve` (`src/popup/views/approval.js`) or
+  a Permit2 amount at the `uint160` max on a swap's `Amount`
+  (`src/shared/uniswap.js`).
+- `All available (V4 open delta)`: a V4 exact-in swap whose `amountIn` is zero.
+  V4 reads that zero as "use the whole open delta", not as a literal zero, so
+  the calldata states no quantity at all. Swap `Amount` line only
+  (`src/shared/uniswap.js`).
+- `None (no minimum guaranteed)`: a zero minimum — the swap guarantees nothing
+  back. It is a literal zero slippage floor on a V2/V3/V4 swap, and it also
+  reaches a `BALANCE_CHECK_ERC20` step: a zero `minBalance`, which once rendered
+  `0.0000` beside the token symbol, now reads this. Swap `Min. received` line
+  (`src/shared/uniswap.js`).
+- `<amount> base units (decimals unknown)`: the token's scale could not be
+  resolved, so the base-unit integer is shown with that caveat rather than
+  formatted (see Unknown token scale above). Reaches both the ERC-20 amount line
+  and the swap's `Amount` and `Min. received` (`unknownDecimalsAmount()` in
+  `src/shared/approvalAmount.js`).
+- `Unknown (not named in the calldata)`: not an amount but the currency itself —
+  the `Token In` or `Token Out` line when nothing in the calldata established
+  which token, shown beside the amount and, like the strings above, a sentence
+  rather than a value (`src/shared/uniswap.js`).
+
 #### Partial USD totals
 
 Prices are fetched for the top 25 tokens only, so an address can hold assets the

TODO.md

@@ -143,16 +143,20 @@ but the review is broader than any of them.
   both routes take, so they behave the same and the button is live for the next
   delete.
 
-- 2026-09-21: The EIP-6963 provider UUID is generated fresh on each page load
-  and never persisted ([#398](https://git.eeqj.de/sneak/AutistMask/issues/398)).
-  It was created once and stored, then announced verbatim to every page on every
-  load and across restarts, so any site — connected or not — could read it as a
-  stable cross-site, cross-session identifier for the install, contradicting the
-  "no tracking" promise. inpage.js now announces a per-load
-  `crypto.randomUUID()` and the `eip6963Uuid` storage key and the
-  `AUTISTMASK_PROVIDER_UUID` content-script message are gone. That key was a
-  standalone storage entry, never part of the versioned `autistmask` profile, so
-  the state schema is untouched and no existing profile is affected.
+- 2026-09-21: `README.md` now documents the approval screen's amount-slot
+  vocabulary and no longer contradicts itself
+  ([#369](https://git.eeqj.de/sneak/AutistMask/issues/369)). The stale claim
+  that a genuine zero still renders `0.0000` is corrected: it holds for the
+  ERC-20 amount, and also for the swap's `Amount` line on a literal-zero
+  `amountIn` in a V2/V3 exact-in swap or a zero `WRAP_ETH`. Only two zeros are
+  stated in words upstream — the swap's `Min. received` (any zero minimum) and
+  its V4 exact-in `Amount` (an `amountIn` of zero, V4's open delta). The
+  amount-display section now names every string a slot can show — a formatted
+  quantity, `Unlimited`, `All available (V4 open delta)`,
+  `None (no minimum guaranteed)`, base units with decimals unknown, and
+  `Unknown (not named in the calldata)` — and records that a zero `minBalance`
+  on a `BALANCE_CHECK_ERC20` step now reads `None (no minimum guaranteed)` where
+  it once read `0.0000`. Docs only; each claim checked against the tree.
 
 - 2026-08-30: An address no longer wraps, or is shortened to fit, in any of the
   common views ([#380](https://git.eeqj.de/sneak/AutistMask/issues/380)). The

src/content/index.js

@@ -5,6 +5,8 @@ const {
     hasBrowserNamespace,
     runtimeApi,
     sendMessage,
+    storageGet,
+    storageSet,
 } = require("../shared/browserApi");
 
 // In Chrome (MV3), inpage.js runs as a MAIN-world content script declared
@@ -19,6 +21,30 @@ if (hasBrowserNamespace()) {
     (document.head || document.documentElement).appendChild(script);
 }
 
+// Send the persisted EIP-6963 provider UUID to the inpage script.
+// Generated once at install time and stored in extension storage.
+(async function sendProviderUuid() {
+    let uuid = null;
+    try {
+        const items = await storageGet("eip6963Uuid");
+        uuid = items?.eip6963Uuid;
+        if (!uuid) {
+            uuid = crypto.randomUUID();
+            await storageSet({ eip6963Uuid: uuid });
+        }
+    } catch {
+        // Storage was unavailable or refused the write. The announcement
+        // still has to go out — a provider that never announces is invisible
+        // to every EIP-6963 dApp — so it goes under a fresh uuid that this
+        // page load will not outlive.
+        if (!uuid) uuid = crypto.randomUUID();
+    }
+    window.postMessage(
+        { type: "AUTISTMASK_PROVIDER_UUID", uuid },
+        location.origin,
+    );
+})();
+
 // Relay requests from the page to the background script
 window.addEventListener("message", (event) => {
     if (event.source !== window) return;

src/content/inpage.js

@@ -204,14 +204,7 @@
                 "</svg>",
         );
 
-    // EIP-6963 wants a fresh UUIDv4 per page load — it identifies one
-    // announcement, so a provider can be told apart from another instance of
-    // itself in the same page. It is generated here and never stored:
-    // announcing one persisted value to every site, on every load and across
-    // restarts, turned it into a stable cross-site, cross-session tracking
-    // identifier any page could read
-    // (https://git.eeqj.de/sneak/AutistMask/issues/398).
-    const providerUuid = crypto.randomUUID();
+    let providerUuid = crypto.randomUUID(); // fallback until real UUID arrives
 
     function buildProviderInfo() {
         return {
@@ -233,6 +226,16 @@
         );
     }
 
+    // Listen for the persisted UUID from the content script
+    function onProviderUuid(event) {
+        if (event.source !== window) return;
+        if (event.data?.type !== "AUTISTMASK_PROVIDER_UUID") return;
+        window.removeEventListener("message", onProviderUuid);
+        providerUuid = event.data.uuid;
+        announceProvider();
+    }
+    window.addEventListener("message", onProviderUuid);
+
     window.addEventListener("eip6963:requestProvider", announceProvider);
     announceProvider();
 

tests/e2e/firefox/run.js

@@ -372,10 +372,10 @@ step("the loopback dApp page gets the real inpage provider", async (env) => {
         STEP_TIMEOUT_MS,
     );
 
-    // EIP-6963, asked of the provider itself. The announcement carries a
-    // UUIDv4 inpage.js generates fresh for this page load (nothing persists
-    // it — see issue #398) and has to name this extension and hand back the
-    // very object on window.ethereum.
+    // EIP-6963, asked of the provider itself. The announcement carries the
+    // uuid src/content/index.js reads out of extension storage — call site 1
+    // in the issue — and it has to name this extension and hand back the very
+    // object on window.ethereum.
     const announced = await d.executeAsync(
         `const done = arguments[arguments.length - 1];
          const onAnnounce = (e) => {
@@ -402,7 +402,7 @@ step("the loopback dApp page gets the real inpage provider", async (env) => {
     );
     assert(
         typeof announced.uuid === "string" && announced.uuid.length === 36,
-        "the announcement carries no provider uuid: " +
+        "the announcement carries no stored provider uuid: " +
             JSON.stringify(announced.uuid),
     );
 

tests/inpageProviderUuid.test.js

@@ -1,103 +0,0 @@
-// The EIP-6963 provider UUID inpage.js announces (src/content/inpage.js).
-//
-// The bug this pins down (issue #398): the UUID used to be generated once,
-// persisted in extension storage, and announced verbatim to every page on
-// every load and across browser restarts, so any site — connected or not —
-// could read a stable cross-site, cross-session identifier for the install.
-// EIP-6963 wants a fresh UUIDv4 per announcement instead. The fix generates
-// it per page load and stores nothing.
-//
-// inpage.js is a bare IIFE injected into the page's JS context, not a module;
-// see tests/inpageErrors.test.js for why it is evaluated against a stub window
-// rather than imported. Here the stub captures the CustomEvent that carries
-// the announcement, so the UUID this file reads is the one a real dApp's
-// eip6963:announceProvider listener would see.
-
-const fs = require("fs");
-const path = require("path");
-const { webcrypto } = require("crypto");
-
-const SOURCE = fs.readFileSync(
-    path.join(__dirname, "..", "src", "content", "inpage.js"),
-    "utf8",
-);
-
-const loadInto = new Function(
-    "window",
-    "self",
-    "crypto",
-    "Event",
-    "CustomEvent",
-    SOURCE,
-);
-
-class StubEvent {
-    constructor(type) {
-        this.type = type;
-    }
-}
-
-class StubCustomEvent extends StubEvent {
-    constructor(type, init) {
-        super(type);
-        this.detail = init && init.detail;
-    }
-}
-
-// Evaluate inpage.js once against a fresh stub window and return every UUID it
-// announced. A `requestProvider` event is dispatched too, so a re-announcement
-// within one load is observed as well as the announcement at load.
-function announcedUuids() {
-    const listeners = {};
-    const uuids = [];
-
-    const win = {
-        addEventListener(type, fn) {
-            (listeners[type] || (listeners[type] = [])).push(fn);
-        },
-        removeEventListener(type, fn) {
-            const fns = listeners[type];
-            if (!fns) return;
-            const i = fns.indexOf(fn);
-            if (i !== -1) fns.splice(i, 1);
-        },
-        postMessage() {},
-        dispatchEvent(event) {
-            if (event.type === "eip6963:announceProvider") {
-                uuids.push(event.detail.info.uuid);
-            }
-            for (const fn of (listeners[event.type] || []).slice()) fn(event);
-            return true;
-        },
-    };
-    win.window = win;
-
-    loadInto(win, win, webcrypto, StubEvent, StubCustomEvent);
-    win.dispatchEvent(new StubEvent("eip6963:requestProvider"));
-    return uuids;
-}
-
-const UUID_V4 =
-    /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/;
-
-describe("the EIP-6963 provider UUID is fresh per page load", () => {
-    test("a load announces a UUIDv4, unprompted, with nothing delivered", () => {
-        const uuids = announcedUuids();
-        expect(uuids.length).toBeGreaterThan(0);
-        expect(uuids[0]).toMatch(UUID_V4);
-    });
-
-    test("every announcement within one load carries the same UUID", () => {
-        const uuids = announcedUuids();
-        expect(uuids.length).toBeGreaterThan(1);
-        expect(new Set(uuids).size).toBe(1);
-    });
-
-    test("two page loads announce different UUIDs", () => {
-        const first = announcedUuids()[0];
-        const second = announcedUuids()[0];
-        expect(first).toMatch(UUID_V4);
-        expect(second).toMatch(UUID_V4);
-        expect(second).not.toBe(first);
-    });
-});