fix(ci,mcp): REGISTRY_STAMP в билд-артефакте + кросс-пакетный CI — закрыть skew build/ vs src/ (#447)

Два структурных слепых пятна: (1) сервер грузит СКОМПИЛИРОВАННЫЙ
packages/mcp/build/index.js, а серверные guard-тесты читают src/tool-specs.ts —
правка src без пересборки оставляет тесты зелёными, но рантайм расходится со
спеками; (2) спеки добавляют в packages/mcp, а parity-тесты живут в jest-сьюте
apps/server — PR, трогающий только пакет, проходит зелёным, сломанная in-app-
проводка всплывает уже на develop (кейс f46d89ea).

- REGISTRY_STAMP: codegen (scripts/gen-registry-stamp.mjs) считает sha256 от
  нормализованного (CRLF→LF, один хвостовой \n снят) сырого текста
  src/tool-specs.ts, пишет src/registry-stamp.generated.ts (gitignored),
  index.ts реэкспортит → попадает в build/. Вшит в build/pretest/watch ДО tsc.
- Loader (dev/test): computeSrcRegistryStamp пересчитывает стамп из src рядом с
  build/index.js (dev-vs-prod по existsSync, любая ошибка → null), сверяет с
  build-стампом → при рассинхроне бросает «build is stale — rebuild». В prod
  (src нет) и на pre-#447 билдах (нет REGISTRY_STAMP) — чистый no-op.
- CI: job mcp-server-parity собирает shared-deps+mcp (регенерит стамп) и гоняет
  ОБА сьюта вместе (mcp node:test + server guard-спеки) — именованный гейт, его
  нельзя случайно расщепить.
- AGENTS.md: правка спеков требует ребилда @docmost/mcp.

Тесты (20): mcp-сайд (детерминизм, нормализация, desync-гард стамп-vs-билд) +
server-сайд (null при отсутствии src = prod no-op; mismatch → throw точного
сообщения; pre-#447 no-op). Кросс-импл equality-гард: один фиксированный вход →
один хэш на ОБЕИХ сторонах, ловит рассинхрон двух нормализаций. Внутреннее
ревью: APPROVE WITH SUGGESTIONS (обе — покрытие guard'а — закрыты этим тестом).
Мутационно: любой из двух normalize-имплов расходится → equality-тест краснеет.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.github/workflows/test.yml

@@ -1,5 +1,13 @@
 name: Test
 
+# NO `paths:` filter on purpose (issue #447). The tool-spec REGISTRY is split
+# across two packages that MUST stay in sync: the specs live in `packages/mcp`
+# but the parity/tier guard tests that read them live in the `apps/server` jest
+# suite. A PR touching only `packages/mcp/**` must therefore still run the SERVER
+# suite (and vice-versa), or an in-app wiring break slips through green and only
+# surfaces on develop after merge. The `test` job below runs BOTH suites via
+# `pnpm -r test` on every PR; the dedicated `mcp-server-parity` job makes that
+# cross-package gate explicit and fast. Do not add a `paths:` filter here.
 on:
   pull_request:
   workflow_call:
@@ -132,3 +140,53 @@ jobs:
       # isolated `docmost_test` DB and migrates it to latest.
       - name: Run server integration tests
         run: pnpm --filter server test:int
+
+  # Cross-package tool-spec parity gate (issue #447). The tool-spec registry lives
+  # in `packages/mcp` but its parity/tier guard tests live in the `apps/server`
+  # jest suite, so a PR touching ONLY one of the two packages must still run BOTH
+  # sides — otherwise an in-app wiring break (e.g. PR #434 drawio) passes the mcp
+  # suite green and only surfaces on develop after merge. The `test` job already
+  # runs everything via `pnpm -r test`; this job is a fast, explicitly-named guard
+  # that runs the mcp `node --test` suite AND the server tool-guard jest specs
+  # together, so the coupling is visible and can never be accidentally split by a
+  # path filter. No Postgres/Redis needed: these specs mock the DB/loader.
+  mcp-server-parity:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up pnpm
+        uses: pnpm/action-setup@v4
+
+      - name: Set up Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: pnpm
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      # Shared deps first (build/ dirs are gitignored; see test.yml build order).
+      - name: Build editor-ext
+        run: pnpm --filter @docmost/editor-ext build
+
+      - name: Build prosemirror-markdown
+        run: pnpm --filter @docmost/prosemirror-markdown build
+
+      # Build the mcp package so build/ carries a FRESH REGISTRY_STAMP (#447): the
+      # build runs gen-registry-stamp.mjs before tsc, so a build/ vs src/ skew
+      # cannot slip into the tests that exercise the loader's stale-check.
+      - name: Build mcp (regenerates REGISTRY_STAMP)
+        run: pnpm --filter @docmost/mcp build
+
+      # mcp side: the standalone MCP server's own tool-spec / instructions guards.
+      - name: Run mcp tool-spec suite
+        run: pnpm --filter @docmost/mcp test
+
+      # server side: the parity + tier guards that read packages/mcp/src/tool-specs
+      # and assert the in-app AI-chat wiring matches it.
+      - name: Run server tool-spec guard specs
+        run: pnpm --filter server exec jest shared-tool-specs.contract tool-tiers ai-chat-tools.service --runInBand

.gitignore

@@ -19,6 +19,11 @@ packages/prosemirror-markdown/build/
 # markdown convention; the package is private and rebuilt at deploy.
 packages/mcp/build/
 
+# mcp REGISTRY_STAMP codegen output (issue #447). Regenerated into src/ by
+# scripts/gen-registry-stamp.mjs on every `build`/`pretest` (before tsc), so it
+# is a build artifact like build/ — never committed, always fresh.
+packages/mcp/src/registry-stamp.generated.ts
+
 # Logs
 logs
 *.log

AGENTS.md

@@ -248,6 +248,22 @@ pnpm collab:dev              # run the collaboration server process standalone (
 > that order). Reach for it whenever you run a consumer package's checks on their
 > own rather than through the full `pnpm build`.
 
+> **Editing an MCP tool spec requires a rebuild (issue #447).** The running
+> server loads the **compiled** `packages/mcp/build/` of `@docmost/mcp` (via the
+> runtime loader in `apps/server/src/core/ai-chat/tools/docmost-client.loader.ts`),
+> but the parity/tier guard tests read `packages/mcp/src/tool-specs.ts`. So if you
+> edit `tool-specs.ts` (any tool name, description, tier, catalog line, or input
+> schema) **without rebuilding**, `build/` and `src/` silently diverge — the tests
+> stay green while the server serves the OLD tools. To close that gap, the build
+> emits a `REGISTRY_STAMP` (a deterministic hash of the tool-specs content, via
+> `scripts/gen-registry-stamp.mjs` before `tsc`); on dev/test startup the loader
+> recomputes it from `src/` and **refuses to start with a "@docmost/mcp build is
+> stale …" error** on a mismatch (a pure no-op in prod, where only `build/` ships).
+> After editing tool specs, rebuild:
+> ```bash
+> pnpm --filter @docmost/mcp build     # or: pnpm --filter @docmost/mcp watch
+> ```
+
 **Lint** (per package — there is no root lint script):
 ```bash
 pnpm --filter server lint    # eslint --fix on server .ts

apps/server/src/core/ai-chat/tools/docmost-client.loader.spec.ts

@@ -0,0 +1,173 @@
+import { createHash } from 'node:crypto';
+import { mkdtempSync, mkdirSync, writeFileSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+
+import { computeSrcRegistryStamp } from './docmost-client.loader';
+
+// The exact message the loader throws on a build/src skew (issue #447). Kept as a
+// literal here so a reworded prod message reddens this test (the message is a
+// developer-facing contract: it tells them how to fix it).
+const STALE_BUILD_MESSAGE =
+  '@docmost/mcp build is stale (tool-specs changed since last build) — run: pnpm --filter @docmost/mcp build';
+
+// Replica of the loader's inline stale-check predicate + throw from
+// `loadDocmostMcp`. That guard is not independently exported (it lives inside the
+// dynamic-import IIFE, wired to a fixed `require.resolve('@docmost/mcp')`), so we
+// exercise the exact same three-condition logic against a stamp produced by the
+// REAL `computeSrcRegistryStamp`. This documents and locks the throw/no-throw
+// behaviour; if the prod predicate changes, this replica must change with it.
+function assertStaleGuard(
+  srcStamp: string | null,
+  registryStamp: string | undefined,
+): void {
+  if (
+    srcStamp !== null &&
+    typeof registryStamp === 'string' &&
+    srcStamp !== registryStamp
+  ) {
+    throw new Error(STALE_BUILD_MESSAGE);
+  }
+}
+
+// Build a throwaway `<pkg>/build/index.js` + optional `<pkg>/src/tool-specs.ts`
+// layout so `computeSrcRegistryStamp(<pkg>/build/index.js)` resolves src the same
+// way the loader does (dirname(dirname(entry))/src/tool-specs.ts).
+function makeFakePackage(toolSpecsSource: string | null): {
+  entry: string;
+  cleanup: () => void;
+} {
+  const root = mkdtempSync(join(tmpdir(), 'mcp-stamp-'));
+  const buildDir = join(root, 'build');
+  mkdirSync(buildDir, { recursive: true });
+  const entry = join(buildDir, 'index.js');
+  writeFileSync(entry, '// fake @docmost/mcp build entry\n', 'utf8');
+  if (toolSpecsSource !== null) {
+    const srcDir = join(root, 'src');
+    mkdirSync(srcDir, { recursive: true });
+    writeFileSync(join(srcDir, 'tool-specs.ts'), toolSpecsSource, 'utf8');
+  }
+  return { entry, cleanup: () => rmSync(root, { recursive: true, force: true }) };
+}
+
+describe('computeSrcRegistryStamp (#447 stale-build guard)', () => {
+  it('returns null when src/tool-specs.ts is absent (prod no-op path)', () => {
+    // A prod image ships only build/, no src/ — the guard must be a silent no-op.
+    const { entry, cleanup } = makeFakePackage(null);
+    try {
+      expect(computeSrcRegistryStamp(entry)).toBeNull();
+    } finally {
+      cleanup();
+    }
+  });
+
+  it('returns null for a bogus package entry (swallowed error path)', () => {
+    // A resolution/read hiccup must NEVER break startup — it resolves to null.
+    expect(
+      computeSrcRegistryStamp('/no/such/pkg/build/index.js'),
+    ).toBeNull();
+  });
+
+  it('computes a 64-char sha256 hex when src/tool-specs.ts exists', () => {
+    const { entry, cleanup } = makeFakePackage('export const specs = 1;\n');
+    try {
+      const stamp = computeSrcRegistryStamp(entry);
+      expect(stamp).toMatch(/^[0-9a-f]{64}$/);
+    } finally {
+      cleanup();
+    }
+  });
+
+  it('normalizes CRLF->LF and strips a single trailing newline', () => {
+    // A CRLF+trailing-newline variant of the same content hashes identically to
+    // the bare-LF form — the guard must not fire on a checkout-style difference.
+    const bare = makeFakePackage('alpha\nbeta');
+    const crlfTrailing = makeFakePackage('alpha\r\nbeta\r\n');
+    try {
+      expect(computeSrcRegistryStamp(crlfTrailing.entry)).toBe(
+        computeSrcRegistryStamp(bare.entry),
+      );
+    } finally {
+      bare.cleanup();
+      crlfTrailing.cleanup();
+    }
+  });
+
+  // CROSS-IMPL EQUALITY (covers reviewer suggestion 2). The SAME fixed input and
+  // EXPECTED hash are asserted in the mcp-side node test
+  // (packages/mcp/test/unit/registry-stamp.test.mjs) against the codegen's
+  // `computeRegistryStamp`. Asserting the SAME pair here against the loader's
+  // `computeSrcRegistryStamp` proves both implementations normalize+hash
+  // identically; a divergence in EITHER side reddens one of the two tests.
+  it('matches the documented cross-impl hash for a fixed input', () => {
+    const FIXED_INPUT = 'line1\r\nline2\n';
+    const EXPECTED =
+      '683376e290829b482c2655745caffa7a1dccfa10afaa62dac2b42dd6c68d0f83';
+    const { entry, cleanup } = makeFakePackage(FIXED_INPUT);
+    try {
+      expect(computeSrcRegistryStamp(entry)).toBe(EXPECTED);
+    } finally {
+      cleanup();
+    }
+  });
+
+  it('the documented EXPECTED is the normalize+sha256 of the fixed input', () => {
+    // Proves EXPECTED is not a magic constant but the documented computation.
+    const FIXED_INPUT = 'line1\r\nline2\n';
+    const normalized = FIXED_INPUT.replace(/\r\n/g, '\n').replace(/\n$/, '');
+    const expected = createHash('sha256')
+      .update(normalized, 'utf8')
+      .digest('hex');
+    const { entry, cleanup } = makeFakePackage(FIXED_INPUT);
+    try {
+      expect(computeSrcRegistryStamp(entry)).toBe(expected);
+    } finally {
+      cleanup();
+    }
+  });
+});
+
+describe('loadDocmostMcp stale-check predicate (#447)', () => {
+  it('THROWS the exact stale message when src stamp != built REGISTRY_STAMP', () => {
+    const { entry, cleanup } = makeFakePackage('export const specs = 1;\n');
+    try {
+      const srcStamp = computeSrcRegistryStamp(entry);
+      expect(srcStamp).not.toBeNull();
+      // Simulate a stale build: build/ carries a DIFFERENT stamp than src.
+      expect(() => assertStaleGuard(srcStamp, 'a'.repeat(64))).toThrow(
+        STALE_BUILD_MESSAGE,
+      );
+    } finally {
+      cleanup();
+    }
+  });
+
+  it('does NOT throw when src stamp equals the built REGISTRY_STAMP', () => {
+    const { entry, cleanup } = makeFakePackage('export const specs = 1;\n');
+    try {
+      const srcStamp = computeSrcRegistryStamp(entry);
+      // Fresh build: build/ stamp == src stamp -> guard is a no-op.
+      expect(() => assertStaleGuard(srcStamp, srcStamp as string)).not.toThrow();
+    } finally {
+      cleanup();
+    }
+  });
+
+  it('does NOT throw when src is absent (prod: srcStamp === null)', () => {
+    // Even against a present-but-mismatched REGISTRY_STAMP, a null src stamp
+    // (prod image with build/ only) must skip the check entirely.
+    expect(() => assertStaleGuard(null, 'a'.repeat(64))).not.toThrow();
+  });
+
+  it('does NOT throw when REGISTRY_STAMP is absent (pre-#447 build)', () => {
+    // An older @docmost/mcp build has no REGISTRY_STAMP export; the guard must be
+    // a no-op so an out-of-date build never wrongly blocks startup.
+    const { entry, cleanup } = makeFakePackage('export const specs = 1;\n');
+    try {
+      const srcStamp = computeSrcRegistryStamp(entry);
+      expect(() => assertStaleGuard(srcStamp, undefined)).not.toThrow();
+    } finally {
+      cleanup();
+    }
+  });
+});

apps/server/src/core/ai-chat/tools/docmost-client.loader.ts

@@ -1,3 +1,6 @@
+import { createHash } from 'node:crypto';
+import { existsSync, readFileSync } from 'node:fs';
+import { dirname, join } from 'node:path';
 import { pathToFileURL } from 'node:url';
 
 /**
@@ -344,6 +347,50 @@ interface DocmostMcpModule {
   // loader in unit tests. The in-app layer treats an absent factory as "signal
   // disabled" — a pure no-op that leaves tool results byte-identical.
   createCommentSignalTracker?: CommentSignalTrackerFactory;
+  // Optional (#447): a deterministic hash of the tool-specs registry content,
+  // generated into build/ by the package's build. Absent on a pre-#447 build (or
+  // the mocked loader in unit tests) — the stale-check below is a NO-OP when it
+  // is missing, so an older build never wrongly fails startup.
+  REGISTRY_STAMP?: string;
+}
+
+/**
+ * Recompute the REGISTRY_STAMP (#447) from the @docmost/mcp source tree, if it is
+ * present. Returns the stamp string, or `null` when the source is absent (a prod
+ * image ships only build/, no src/). MUST stay byte-for-byte identical to
+ * packages/mcp/scripts/gen-registry-stamp.mjs's `computeRegistryStamp` so the
+ * build-time and src-time hashes agree: same input file (src/tool-specs.ts), same
+ * normalization (CRLF -> LF, strip a single trailing newline), same sha256.
+ *
+ * DEV vs PROD detection is by FILE EXISTENCE, not NODE_ENV: we resolve the
+ * package's own directory from `require.resolve('@docmost/mcp')` (which points at
+ * build/index.js) and look for ../src/tool-specs.ts next to it. In a dev/test
+ * worktree that file exists; in a prod image (build/ only, src/ stripped) it does
+ * not, so this returns null and the caller skips the check. Any error (ENOENT, a
+ * bad resolve) is swallowed to null — the stale-check must NEVER break startup.
+ *
+ * Exported for unit testing (docmost-client.loader.spec.ts): the export keyword
+ * is behaviourally a no-op — the module-internal caller `loadDocmostMcp` is
+ * unaffected. The test drives the null (no-src) path and asserts this
+ * normalize+sha256 stays identical to the codegen's `computeRegistryStamp`.
+ */
+export function computeSrcRegistryStamp(packageEntry: string): string | null {
+  try {
+    // packageEntry is <pkg>/build/index.js; the source lives at <pkg>/src/.
+    const toolSpecsPath = join(
+      dirname(dirname(packageEntry)),
+      'src',
+      'tool-specs.ts',
+    );
+    if (!existsSync(toolSpecsPath)) return null; // prod: no src tree -> skip.
+    const source = readFileSync(toolSpecsPath, 'utf8');
+    const normalized = source.replace(/\r\n/g, '\n').replace(/\n$/, '');
+    return createHash('sha256').update(normalized, 'utf8').digest('hex');
+  } catch {
+    // Never let a resolution/read hiccup break server startup — treat as "no
+    // src available" and skip the check (identical to the prod no-op path).
+    return null;
+  }
 }
 
 // TS with module:commonjs downlevels a literal `import()` to `require()`, which
@@ -375,6 +422,23 @@ export async function loadDocmostMcp(): Promise<{
       const mod = (await esmImport(
         pathToFileURL(entry).href,
       )) as DocmostMcpModule;
+      // #447 stale-build guard (dev/test only). The server loads the COMPILED
+      // build/ of @docmost/mcp, but the parity/tier guard tests read src/. If a
+      // tool spec is edited in src without rebuilding the package, build/ and src/
+      // silently diverge and the running server serves the OLD tools. Here we
+      // recompute the stamp from src/tool-specs.ts and compare it to the stamp
+      // baked into build/. In PROD the src tree is absent (image ships build/
+      // only), so computeSrcRegistryStamp returns null and this is a pure no-op.
+      const srcStamp = computeSrcRegistryStamp(entry);
+      if (
+        srcStamp !== null &&
+        typeof mod.REGISTRY_STAMP === 'string' &&
+        srcStamp !== mod.REGISTRY_STAMP
+      ) {
+        throw new Error(
+          '@docmost/mcp build is stale (tool-specs changed since last build) — run: pnpm --filter @docmost/mcp build',
+        );
+      }
       return mod;
     })().catch((err) => {
       // Do not cache a rejected import — allow the next call to retry.

packages/mcp/package.json

@@ -13,10 +13,11 @@
     "docmost-mcp": "./build/stdio.js"
   },
   "scripts": {
-    "build": "tsc",
+    "gen:stamp": "node scripts/gen-registry-stamp.mjs",
+    "build": "node scripts/gen-registry-stamp.mjs && tsc",
     "start": "node build/stdio.js",
-    "watch": "tsc --watch",
-    "pretest": "tsc",
+    "watch": "node scripts/gen-registry-stamp.mjs && tsc --watch",
+    "pretest": "node scripts/gen-registry-stamp.mjs && tsc",
     "test": "node --test \"test/unit/*.test.mjs\" \"test/mock/*.test.mjs\"",
     "test:unit": "node --test \"test/unit/*.test.mjs\"",
     "test:mock": "node --test \"test/mock/*.test.mjs\"",

packages/mcp/scripts/gen-registry-stamp.mjs

@@ -0,0 +1,67 @@
+// Codegen: emit src/registry-stamp.generated.ts with a REGISTRY_STAMP hash of
+// the tool-specs REGISTRY CONTENT, so a build/ vs src/ skew (issue #447) is
+// detectable at runtime.
+//
+// WHY hash the raw source text (not extracted structured data):
+// SHARED_TOOL_SPECS carries `buildShape` functions (the input SCHEMAS) which are
+// NOT serializable. The input schema is exactly one of the things that MUST stay
+// in sync between build/ and src/, so we cannot drop it from the hash. Rather
+// than probe zod with a fragile shim to reconstruct the schema shape, we hash the
+// STABLE, deterministic source TEXT of tool-specs.ts. That text fully captures
+// every field that must stay in sync — mcpName, inAppKey, description, tier,
+// catalogLine AND the buildShape bodies (input schemas) — with zero probing
+// fragility. Any edit to a spec (a renamed tool, a reworded description, a
+// changed schema field) changes the text and therefore the stamp.
+//
+// DETERMINISM: the hash is computed over the file bytes with line endings
+// normalized to LF and a single trailing newline stripped, so a CRLF checkout or
+// an editor's trailing-newline habit cannot make build/ and src/ disagree. No
+// Date.now / randomness. The loader's dev-only stale-check (docmost-client.loader.ts)
+// re-runs THIS SAME normalization + sha256 over src/tool-specs.ts and compares to
+// the built REGISTRY_STAMP; the two must compute identically.
+//
+// This script runs from the `build` and `pretest` npm scripts BEFORE tsc, so
+// build/ always carries a stamp derived from the tool-specs.ts that was compiled.
+
+import { createHash } from 'node:crypto';
+import { readFileSync, writeFileSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+import { dirname, join } from 'node:path';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const SRC_DIR = join(__dirname, '..', 'src');
+const TOOL_SPECS_PATH = join(SRC_DIR, 'tool-specs.ts');
+const OUT_PATH = join(SRC_DIR, 'registry-stamp.generated.ts');
+
+/**
+ * Deterministic stamp of the tool-specs registry content. Kept as a plain
+ * function (exported) so the algorithm has a single home; the loader duplicates
+ * only the tiny normalize+sha256 steps because it lives in the CJS server build
+ * and cannot import this ESM script. If you change the normalization here, mirror
+ * it in apps/server/src/core/ai-chat/tools/docmost-client.loader.ts.
+ */
+export function computeRegistryStamp(toolSpecsSource) {
+  const normalized = toolSpecsSource.replace(/\r\n/g, '\n').replace(/\n$/, '');
+  return createHash('sha256').update(normalized, 'utf8').digest('hex');
+}
+
+function main() {
+  const source = readFileSync(TOOL_SPECS_PATH, 'utf8');
+  const stamp = computeRegistryStamp(source);
+  const out =
+    '// AUTO-GENERATED by scripts/gen-registry-stamp.mjs — DO NOT EDIT BY HAND.\n' +
+    '// A deterministic hash of src/tool-specs.ts content (tool names, descriptions,\n' +
+    '// tiers, catalog lines and input schemas). Regenerated on every build/pretest\n' +
+    '// so build/ always matches the compiled src. The in-app loader recomputes this\n' +
+    '// from src and refuses to run on a mismatch (issue #447). This file is\n' +
+    '// gitignored and produced by the build — see .gitignore.\n' +
+    `export const REGISTRY_STAMP = ${JSON.stringify(stamp)};\n`;
+  writeFileSync(OUT_PATH, out, 'utf8');
+  // eslint-disable-next-line no-console
+  console.log(`gen-registry-stamp: wrote ${OUT_PATH} (${stamp.slice(0, 12)}…)`);
+}
+
+// Only run when invoked directly (not when imported for computeRegistryStamp).
+if (process.argv[1] && fileURLToPath(import.meta.url) === process.argv[1]) {
+  main();
+}

packages/mcp/src/index.ts

@@ -29,6 +29,14 @@ export { destroyAllSessions } from "./lib/collab-session.js";
 export { SHARED_TOOL_SPECS } from "./tool-specs.js";
 export type { SharedToolSpec } from "./tool-specs.js";
 
+// Re-export the build-time REGISTRY_STAMP (issue #447): a deterministic hash of
+// the tool-specs registry content, generated into src/registry-stamp.generated.ts
+// by scripts/gen-registry-stamp.mjs BEFORE tsc, so it lands in build/. The in-app
+// loader recomputes the same hash from src/tool-specs.ts (dev/test only) and
+// refuses to run on a mismatch, catching a build/ vs src/ skew (a spec edited in
+// src without rebuilding the package the server actually loads from build/).
+export { REGISTRY_STAMP } from "./registry-stamp.generated.js";
+
 // Re-export the shared "new comments: N" signal helper (#417) so the in-app
 // layer reads the SAME watermark/debounce/injection-safe line builder off the
 // loaded module (same pattern as SHARED_TOOL_SPECS). Both surfaces then differ

packages/mcp/test/unit/registry-stamp.test.mjs

@@ -0,0 +1,101 @@
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { createHash } from "node:crypto";
+import { readFileSync } from "node:fs";
+import { fileURLToPath } from "node:url";
+import { dirname, join } from "node:path";
+
+import { computeRegistryStamp } from "../../scripts/gen-registry-stamp.mjs";
+import { REGISTRY_STAMP } from "../../build/index.js";
+
+// Guard tests for the build/src-skew stamp (issue #447). The codegen script
+// exports `computeRegistryStamp(sourceText)` — a sha256 over normalized source
+// text (CRLF->LF, single trailing newline stripped). The in-app loader
+// (apps/server/.../docmost-client.loader.ts) DUPLICATES that normalize+sha256 to
+// recompute the stamp from src and refuse a stale build. These tests pin the
+// algorithm's behaviour AND assert the built stamp matches the current src, so a
+// stale generated file OR a normalize divergence reddens.
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const TOOL_SPECS_PATH = join(__dirname, "..", "..", "src", "tool-specs.ts");
+
+test("computeRegistryStamp is deterministic: same input -> same hash", () => {
+  const input = "export const X = 1;\nexport const Y = 2;\n";
+  assert.equal(computeRegistryStamp(input), computeRegistryStamp(input));
+});
+
+test("computeRegistryStamp returns a 64-char lowercase hex sha256", () => {
+  const stamp = computeRegistryStamp("anything");
+  assert.match(stamp, /^[0-9a-f]{64}$/);
+});
+
+test("normalizes CRLF vs LF: the same content hashes equal", () => {
+  const lf = "line1\nline2\nline3";
+  const crlf = "line1\r\nline2\r\nline3";
+  assert.equal(computeRegistryStamp(crlf), computeRegistryStamp(lf));
+});
+
+test("normalizes a trailing newline: with/without a final \\n hashes equal", () => {
+  const noTrailing = "alpha\nbeta";
+  const trailing = "alpha\nbeta\n";
+  assert.equal(computeRegistryStamp(trailing), computeRegistryStamp(noTrailing));
+});
+
+test("a CRLF checkout WITH a trailing CRLF still hashes equal to bare LF", () => {
+  // A worst-case Windows checkout: CRLF line endings + a trailing CRLF. Both the
+  // \r\n->\n replace and the trailing-newline strip must apply for parity.
+  const bare = "alpha\nbeta";
+  const crlfTrailing = "alpha\r\nbeta\r\n";
+  assert.equal(
+    computeRegistryStamp(crlfTrailing),
+    computeRegistryStamp(bare),
+  );
+});
+
+test("a real content change hashes differently", () => {
+  const before = "export const description = 'search a page';\n";
+  const after = "export const description = 'search a PAGE';\n";
+  assert.notEqual(computeRegistryStamp(before), computeRegistryStamp(after));
+});
+
+// Only a SINGLE trailing newline is stripped — a second blank line is content and
+// must change the hash. This pins the exact `/\n$/` semantics the loader mirrors.
+test("only ONE trailing newline is stripped (two differ from one)", () => {
+  assert.notEqual(
+    computeRegistryStamp("x\n"),
+    computeRegistryStamp("x\n\n"),
+  );
+});
+
+// Cross-impl equality against a fixed, documented input. The SAME literal input
+// and expected hash are asserted in the server-side jest test
+// (docmost-client.loader.spec.ts). If either side's normalize+sha256 ever
+// diverges, one of the two tests reddens. Input exercises BOTH normalize steps.
+test("fixed-input hash matches the documented cross-impl value", () => {
+  const FIXED_INPUT = "line1\r\nline2\n";
+  const EXPECTED =
+    "683376e290829b482c2655745caffa7a1dccfa10afaa62dac2b42dd6c68d0f83";
+  assert.equal(computeRegistryStamp(FIXED_INPUT), EXPECTED);
+});
+
+// DESYNC GUARD (covers reviewer suggestion 2). Recompute the stamp from the
+// actual src/tool-specs.ts and assert it equals the REGISTRY_STAMP baked into the
+// freshly-built build/index.js. This reddens if the generated file is stale OR if
+// the codegen normalize ever diverges from what produced the built stamp.
+test("built REGISTRY_STAMP equals the stamp recomputed from src/tool-specs.ts", () => {
+  const source = readFileSync(TOOL_SPECS_PATH, "utf8");
+  assert.equal(computeRegistryStamp(source), REGISTRY_STAMP);
+});
+
+// Sanity: the fixed-input helper computes the SAME way the codegen does, proving
+// the EXPECTED constant above is not an arbitrary magic value but the documented
+// normalize+sha256 of FIXED_INPUT. Belt-and-braces so a bad EXPECTED can't hide a
+// real regression.
+test("the documented EXPECTED constant is the normalize+sha256 of FIXED_INPUT", () => {
+  const FIXED_INPUT = "line1\r\nline2\n";
+  const normalized = FIXED_INPUT.replace(/\r\n/g, "\n").replace(/\n$/, "");
+  const expected = createHash("sha256")
+    .update(normalized, "utf8")
+    .digest("hex");
+  assert.equal(computeRegistryStamp(FIXED_INPUT), expected);
+});