@@ -182,7 +182,16 @@ describe('os create: a name npm refuses is refused before anything is written',
 
         // ⛔ The asymmetry is correct, not a second defect: `init`'s argument is
         // the package name, so npm's ceiling is already measured against it.
-        const inited = await runCli(['init', COMPOSED_TOO_LONG], initCwd);
+        //
+        // `--no-install`: what is judged is that `init` ACCEPTS the name, and
+        // it refuses an invalid one before the first write, long before any
+        // install. Without the flag, `init` ran `<pm> install` in this
+        // `tmpdir()` scaffold, which carries no `packageManager` pin on
+        // purpose: under Corepack that resolved `pnpm@latest` from the public
+        // registry and then fetched the scaffold's dependencies from it —
+        // measured: a registry answering HTTP 429 turned this exit 0 into a
+        // failure with nothing about the name changed.
+        const inited = await runCli(['init', COMPOSED_TOO_LONG, '--no-install'], initCwd);
         expect(inited.code).toBe(0);
       } finally {
         rmSync(createCwd, { recursive: true, force: true });
 
@@ -46,8 +46,8 @@
  */
 
 import { describe, it, expect, beforeAll, afterAll } from 'vitest';
-import { execFile } from 'node:child_process';
-import { mkdtempSync, rmSync, writeFileSync } from 'node:fs';
+import { execFile, execFileSync } from 'node:child_process';
+import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from 'node:fs';
 import { tmpdir } from 'node:os';
 import { join, resolve } from 'node:path';
 import { fileURLToPath } from 'node:url';
@@ -59,6 +59,54 @@ const HERE = resolve(fileURLToPath(import.meta.url), '..');
 const CLI = resolve(HERE, '../bin/run-dev.js');
 const TSX = resolve(HERE, '../../../node_modules/.bin/tsx');
 
+const PACKAGE_ROOT = resolve(HERE, '..');
+
+/**
+ * The `packageManager` pin both fixtures carry, as `pnpm@VERSION`.
+ *
+ * Why the fixtures carry one: both live under `tmpdir()`, outside the
+ * repository, and the spawned `os dev` runs `pnpm … dev` inside them. Under
+ * Corepack (CI's `setup-pnpm`), a `pnpm` run with no `packageManager` in reach
+ * resolves `pnpm@latest` from the public registry — measured: a registry
+ * answering HTTP 429 failed this file's two pnpm-running cases with
+ * `os dev ended with code 1` and `expected 1 to be +0`, the shape CI saw.
+ * `COREPACK_DEFAULT_TO_LATEST=0` is NOT the same fix: it swaps `latest` for
+ * Corepack's own bundled default, which CI's store does not hold, and the
+ * registry is reached for that instead.
+ *
+ * Why the pin is DERIVED and not read: VERSION is what `pnpm --version`
+ * answers with this package as its cwd, which is the repository's root pin
+ * reached through Corepack's own walk up to the nearest manifest declaring
+ * one. That is the version CI's Corepack store already holds, so the fixtures
+ * resolve it with no network call, and nothing is copied by hand. Reading the
+ * root `package.json` from here instead would make it a declared input of this
+ * package's tests (`check:cross-package-test-inputs`), which would put cli's
+ * whole PR-tier suite on every PR that edits that manifest. The spec carries no
+ * integrity hash; Corepack resolves the stored version by its number.
+ *
+ * ⛔ The blind spot this leaves, stated so it is not read as covered: the pin
+ * is an UNDECLARED input. A PR that bumps only the root pin does not re-run
+ * this file in CI, exactly as it re-runs none of this suite's other `pnpm -v`
+ * and `pnpm pack` callers, which resolve pnpm through the same walk. A pnpm
+ * whose no-projects sentence changed would first go red on a later PR that
+ * re-runs cli's tests.
+ */
+function derivePackageManagerPin(): string {
+  const answer = execFileSync('pnpm', ['--version'], {
+    cwd: PACKAGE_ROOT,
+    encoding: 'utf8',
+    stdio: ['ignore', 'pipe', 'pipe'],
+    env: childEnv(),
+  }).trim();
+  if (!/^\d+\.\d+\.\d+(-[0-9A-Za-z.-]+)?$/.test(answer)) {
+    throw new Error(
+      `\`pnpm --version\` in ${PACKAGE_ROOT} answered ${JSON.stringify(answer)}, not a version; ` +
+        'without one these fixtures carry no pin and Corepack would fetch a pnpm from the registry',
+    );
+  }
+  return `pnpm@${answer}`;
+}
+
 /** oclif + tsx cold start, with every command module loaded; ~2-10 s when healthy. */
 const RUN_TIMEOUT_MS = 180_000;
 
@@ -143,27 +191,46 @@ describe('the watch opt-out is reachable', () => {
   });
 });
 
+let fixtureRoot: string;
+let packageManagerPin: string;
 let projectDir: string;
 let workspaceDir: string;
 let watchEqualsFalse: Run;
 let noWatchAtWorkspace: Run;
 let bareAtWorkspace: Run;
 
 beforeAll(async () => {
+  // Both fixtures sit under one root whose manifest carries the pin (see
+  // `derivePackageManagerPin`). Above `projectDir`, not in it: a `package.json`
+  // inside `projectDir` makes it a project, and pnpm then answers
+  // `No projects matched the filters` instead of the `No projects found`
+  // this file pins. Corepack walks up to the nearest manifest declaring a
+  // `packageManager`; pnpm's no-projects answer reads `projectDir` alone.
+  packageManagerPin = derivePackageManagerPin();
+  fixtureRoot = mkdtempSync(join(tmpdir(), 'os-dev-no-watch-'));
+  writeFileSync(
+    join(fixtureRoot, 'package.json'),
+    `${JSON.stringify({ private: true, packageManager: packageManagerPin })}\n`,
+  );
+
   // A project directory: a config file, and no pnpm workspace above it.
-  projectDir = mkdtempSync(join(tmpdir(), 'os-dev-no-watch-project-'));
+  projectDir = join(fixtureRoot, 'project');
+  mkdirSync(projectDir);
   writeFileSync(join(projectDir, 'objectstack.config.ts'), 'export default {};\n');
 
   // A workspace root whose own `dev` script announces that it ran — so the
   // `--no-watch` refusal below is measured against a fixture that DOES start
-  // something when asked (`bareAtWorkspace` is that control).
-  workspaceDir = mkdtempSync(join(tmpdir(), 'os-dev-no-watch-workspace-'));
+  // something when asked (`bareAtWorkspace` is that control). Its own manifest
+  // carries the pin too: the nearest one is what Corepack reads first.
+  workspaceDir = join(fixtureRoot, 'workspace');
+  mkdirSync(workspaceDir);
   writeFileSync(join(workspaceDir, 'pnpm-workspace.yaml'), 'packages: []\n');
   writeFileSync(
     join(workspaceDir, 'package.json'),
     `${JSON.stringify({
       name: 'os-dev-no-watch-fixture',
       private: true,
+      packageManager: packageManagerPin,
       scripts: { dev: `node -e "console.log('${DEV_SCRIPT_MARK}')"` },
     })}\n`,
   );
@@ -176,8 +243,7 @@ beforeAll(async () => {
 }, RUN_TIMEOUT_MS);
 
 afterAll(() => {
-  rmSync(projectDir, { recursive: true, force: true });
-  rmSync(workspaceDir, { recursive: true, force: true });
+  if (fixtureRoot) rmSync(fixtureRoot, { recursive: true, force: true });
 });
 
 describe('a PACKAGE that selects no workspace project fails', () => {
 
@@ -30,23 +30,66 @@
 
 import { afterAll, beforeAll, describe, expect, it } from 'vitest';
 import { execFile } from 'node:child_process';
-import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from 'node:fs';
+import { chmodSync, mkdirSync, mkdtempSync, rmSync, writeFileSync } from 'node:fs';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { delimiter, join } from 'node:path';
 import { FILE_REFERENCES_MIGRATION_ID } from '@objectstack/spec/system';
 
 import { CLI, TSX, childEnv } from './helpers/serve-process.js';
 import { linkSpec } from './helpers/define-stack-fixture.js';
 
 interface Run { code: number; stdout: string; stderr: string }
 
+/**
+ * The version a stub `pnpm` answers with. `os doctor` runs `pnpm -v` in its own
+ * cwd, and every cwd here is a `tmpdir()` fixture with no `packageManager` in
+ * reach: under Corepack (CI's `setup-pnpm`) a real `pnpm` there resolves
+ * `pnpm@latest` from the public registry — measured: two registry requests per
+ * run of this file, one per doctor child. Doctor degrades a failed probe to a
+ * row, so a refused registry never reddened this file; it reached the network
+ * all the same. Which pnpm answers is not what these pins judge, so a stub on
+ * `PATH` answers instead, and `doctor` asserts below that the stub is what it
+ * reached.
+ */
+const STUB_PNPM_VERSION = '0.0.0-package-owned-readers-stub';
+
+/** A `pnpm` that answers `-v` and refuses anything else, loudly. */
+function writeStubPnpm(binDir: string): void {
+  mkdirSync(binDir, { recursive: true });
+  const bin = join(binDir, 'pnpm');
+  writeFileSync(
+    bin,
+    [
+      '#!/bin/sh',
+      'case "$1" in',
+      `  -v|--version) echo ${STUB_PNPM_VERSION}; exit 0 ;;`,
+      'esac',
+      'echo "stub pnpm: unexpected invocation: $*" >&2',
+      'exit 97',
+      '',
+    ].join('\n'),
+  );
+  chmodSync(bin, 0o755);
+}
+
+let stubBinDir = '';
+
 function runCli(args: string[], cwd: string): Promise<Run> {
   return new Promise((resolvePromise) => {
     execFile(
       TSX,
       [CLI, ...args],
       // Artifact-less on purpose: the config is the only input these commands read.
-      { cwd, maxBuffer: 16 * 1024 * 1024, env: childEnv({ NO_COLOR: '1', OS_ARTIFACT_PATH: join(cwd, 'dist', 'objectstack.json') }) },
+      // The stub `pnpm` leads `PATH` for every child; only `doctor` calls it.
+      {
+        cwd,
+        maxBuffer: 16 * 1024 * 1024,
+        env: childEnv({
+          NO_COLOR: '1',
+          OS_ARTIFACT_PATH: join(cwd, 'dist', 'objectstack.json'),
+          PATH: `${stubBinDir}${delimiter}${process.env.PATH ?? ''}`,
+        }),
+      },
       (err, stdout, stderr) => {
         const code = err ? (typeof (err as { code?: unknown }).code === 'number' ? (err as { code: number }).code : 1) : 0;
         resolvePromise({ code, stdout: String(stdout), stderr: String(stderr) });
@@ -97,6 +140,8 @@ let r: Record<string, Run> = {};
 
 beforeAll(async () => {
   root = mkdtempSync(join(tmpdir(), 'os-package-owned-command-readers-'));
+  stubBinDir = join(root, 'bin');
+  writeStubPnpm(stubBinDir);
   for (const [name, source] of Object.entries(CONFIGS)) {
     const dir = join(root, name);
     mkdirSync(dir, { recursive: true });
@@ -137,6 +182,12 @@ describe('#22288 — os doctor runs its metadata checks over every package', ()
       expect(unused.join('\n'), out).toMatch(/"pco_note"/);
       expect(unused.join('\n'), out).toMatch(/"pco_ticket"/);
     });
+
+    it(`${shape === 'two' ? 'two packages' : 'control, one package'}: doctor's pnpm probe reached the stub, not the registry`, () => {
+      const run = r[`doctor:${shape}`];
+      const out = run.stdout + run.stderr;
+      expect(out, out).toContain(STUB_PNPM_VERSION);
+    });
   }
 });