diff --git a/package.json b/package.json
index 58eadab09..f04770584 100644
--- a/package.json
+++ b/package.json
@@ -122,7 +122,7 @@
     "lint:frontmatter-scalar-broad-grep": "node scripts/lint-frontmatter-scalar-broad-grep.cjs",
     "lint:removed-but-needed": "node scripts/lint-removed-but-needed.cjs",
     "lint:response-language": "node scripts/lint-response-language-coverage.cjs",
-    "lint:ci": "npm run lint && npm run lint:skill-deps && npm run lint:generated-sync && node scripts/lint-test-file-count.cjs && node scripts/lint-command-contract.cjs && node scripts/lint-pr-check-project-dir.cjs && npm run lint:legacy-name && node scripts/lint-regression-test-names.cjs && node scripts/lint-allow-test-rule-refs.cjs && node scripts/lint-resolution-provenance.cjs && node scripts/lint-portable-timeout.cjs && node scripts/lint-portable-grep.cjs && node scripts/validate-registry.cjs && node scripts/lint-table-schema-drift.cjs && node scripts/lint-fix-has-regression-tests.cjs && node scripts/lint-example-parser-parity.cjs && node scripts/lint-docs-command-form.cjs && node scripts/lint-plan-count-drift.cjs && node scripts/lint-milestone-window-drift.cjs && node scripts/lint-phase-enumeration-drift.cjs && node scripts/lint-planning-prompt-drift.cjs && node scripts/lint-unreachable-guard-drift.cjs && node scripts/lint-completion-ratio-drift.cjs && node scripts/lint-slug-derivation-drift.cjs && node scripts/lint-state-field-drift.cjs && node scripts/lint-state-write-path-drift.cjs && node scripts/lint-completion-predicate-drift.cjs && node scripts/lint-planning-snapshot-bypass-drift.cjs && node scripts/lint-health-diagnostic-rule-table.cjs && node scripts/lint-planning-artifact-writer-drift.cjs && node scripts/lint-frontmatter-scalar-broad-grep.cjs && node scripts/lint-removed-but-needed.cjs && node scripts/lint-no-adhoc-regex-escape.cjs && node scripts/lint-vendored-deps.cjs && node scripts/lint-docs-guard-registration.cjs && node scripts/lint-source-test-name-collision.cjs && npm run lint:hooks-runtime-build-seam && node scripts/check-contract-drift.cjs && node scripts/lint-mutation-test-derivation-drift.cjs && node scripts/lint-seam-enforcement.cjs && node scripts/lint-workflow-shellcheck.cjs && npm run lint:response-language",
+    "lint:ci": "npm run lint && npm run lint:skill-deps && npm run lint:generated-sync && node scripts/lint-test-file-count.cjs && node scripts/lint-command-contract.cjs && node scripts/lint-pr-check-project-dir.cjs && npm run lint:legacy-name && node scripts/lint-regression-test-names.cjs && node scripts/lint-allow-test-rule-refs.cjs && node scripts/lint-resolution-provenance.cjs && node scripts/lint-portable-timeout.cjs && node scripts/lint-portable-grep.cjs && node scripts/lint-allowed-tools-parity.cjs && node scripts/validate-registry.cjs && node scripts/lint-table-schema-drift.cjs && node scripts/lint-fix-has-regression-tests.cjs && node scripts/lint-example-parser-parity.cjs && node scripts/lint-docs-command-form.cjs && node scripts/lint-plan-count-drift.cjs && node scripts/lint-milestone-window-drift.cjs && node scripts/lint-phase-enumeration-drift.cjs && node scripts/lint-planning-prompt-drift.cjs && node scripts/lint-unreachable-guard-drift.cjs && node scripts/lint-completion-ratio-drift.cjs && node scripts/lint-slug-derivation-drift.cjs && node scripts/lint-state-field-drift.cjs && node scripts/lint-state-write-path-drift.cjs && node scripts/lint-completion-predicate-drift.cjs && node scripts/lint-planning-snapshot-bypass-drift.cjs && node scripts/lint-health-diagnostic-rule-table.cjs && node scripts/lint-planning-artifact-writer-drift.cjs && node scripts/lint-frontmatter-scalar-broad-grep.cjs && node scripts/lint-removed-but-needed.cjs && node scripts/lint-no-adhoc-regex-escape.cjs && node scripts/lint-vendored-deps.cjs && node scripts/lint-docs-guard-registration.cjs && node scripts/lint-source-test-name-collision.cjs && npm run lint:hooks-runtime-build-seam && node scripts/check-contract-drift.cjs && node scripts/lint-mutation-test-derivation-drift.cjs && node scripts/lint-seam-enforcement.cjs && node scripts/lint-workflow-shellcheck.cjs && npm run lint:response-language",
     "lint:allow-test-rule-refs": "node scripts/lint-allow-test-rule-refs.cjs",
     "lint:regression-names": "node scripts/lint-regression-test-names.cjs",
     "lint:descriptions": "node scripts/lint-descriptions.cjs",
diff --git a/scripts/lint-allowed-tools-parity.cjs b/scripts/lint-allowed-tools-parity.cjs
new file mode 100644
index 000000000..a554e0310
--- /dev/null
+++ b/scripts/lint-allowed-tools-parity.cjs
@@ -0,0 +1,221 @@
+#!/usr/bin/env node
+'use strict';
+
+/**
+ * lint-allowed-tools-parity.cjs — catch `allowed-tools` frontmatter that
+ * declares `Bash` but omits `Grep` (#4394, follow-up to #3085).
+ *
+ * ## Why
+ *
+ * `gen-plugin-skills.cjs --check` already guarantees `skills/*` /SKILL.md`
+ * matches byte-for-byte what `commands/gsd/*.md` generates, so the two trees
+ * cannot silently diverge FROM EACH OTHER. Nothing guarded the shape #3085
+ * actually found: a command shipping `Bash` without `Grep` purely by
+ * omission, identical in both trees and therefore invisible to a parity
+ * check that only compares them to each other.
+ *
+ * That drift ran long enough for 29 of 71 skills to lack a tool most of
+ * their siblings already declared, and it surfaced through a manual audit
+ * rather than any gate. A command that can shell out but cannot Grep does
+ * not fail loudly — it quietly reaches for `Bash` + `grep` instead, which is
+ * slower, less structured, and (per `lint-portable-grep.cjs`) a portability
+ * hazard of its own on hosts without GNU grep.
+ *
+ * ## The rule
+ *
+ * A command whose `allowed-tools` includes `Bash` must also include `Grep`,
+ * unless it is on the exemption list below.
+ *
+ * Detection only. This lint never edits a command's `allowed-tools`.
+ *
+ * ## Why an exemption list rather than a heuristic
+ *
+ * The alternative — inferring from a command's body whether it "really"
+ * needs Grep — would make the rule's verdict depend on prose that changes
+ * constantly, and produce a lint whose failures nobody can predict. A short
+ * literal list keeps every exemption a reviewable one-line diff, and the
+ * staleness check below stops it becoming a dumping ground: an entry that no
+ * longer needs to be there fails just as loudly as a missing tool.
+ */
+
+const fs = require('fs');
+const path = require('path');
+const { ExitError, runMain } = require('./lib/cli-exit.cjs');
+
+const ROOT = path.resolve(__dirname, '..');
+const DEFAULT_ROOT = 'commands/gsd';
+
+/**
+ * Commands allowed to declare `Bash` without `Grep`.
+ *
+ * Keyed by command stem (the filename without `.md`), with the reason inline
+ * so changing the set is a one-line, reviewable diff.
+ *
+ * #4394 named eight candidates from the #3085 review: the six `gsd-ns-*`
+ * namespace dispatchers, `gsd-help`, and `gsd-surface`. Seven of those turn
+ * out not to need an entry at all — they do not declare `Bash` in the first
+ * place, so the rule never reaches them:
+ *
+ *   ns-context/ns-ideate/ns-manage/ns-project/ns-review/ns-workflow  Read + Skill
+ *   help                                                             Read
+ *
+ * Listing them anyway would be seven pre-forgiven commands: the day one of
+ * them gained `Bash`, the omission it was granted an exemption for would
+ * pass silently. The staleness check in `scan()` below is what surfaced
+ * this, and it is why the list stays minimal — an exemption is a real
+ * suppression, not documentation.
+ */
+const EXEMPT = new Map([
+  // Toggles which skills are surfaced. Mutates the install tree through the
+  // installer's own seams rather than by searching project files, so `Bash`
+  // here is not standing in for a search it cannot perform.
+  ['surface', 'mutates the install surface via installer seams, not by searching the project'],
+]);
+
+/**
+ * Parse an `allowed-tools` frontmatter value.
+ *
+ * Handles both shapes the corpus uses: a YAML block sequence
+ *
+ *     allowed-tools:
+ *       - Read
+ *       - Bash
+ *
+ * and an inline scalar or flow sequence (`allowed-tools: Read, Bash` /
+ * `allowed-tools: [Read, Bash]`). Returns `null` when the key is absent,
+ * which is NOT a violation — a command with no `allowed-tools` at all
+ * declares no `Bash` either, so this rule has nothing to say about it.
+ *
+ * Deliberately not a YAML parser: the frontmatter here is a fixed, shallow
+ * shape, and pulling in a parser to read one list would be a dependency
+ * bought for a single key.
+ *
+ * @param {string} text  full file contents
+ * @returns {string[] | null}  declared tool names, or null when the key is absent
+ */
+function parseAllowedTools(text) {
+  const lines = String(text).split(/\r?\n/);
+  const keyIndex = lines.findIndex((l) => /^allowed-tools:/.test(l));
+  if (keyIndex === -1) return null;
+
+  const inline = lines[keyIndex].replace(/^allowed-tools:/, '').trim();
+  if (inline) {
+    return inline
+      .replace(/^\[/, '')
+      .replace(/\]$/, '')
+      .split(',')
+      .map((s) => s.trim().replace(/^['"]|['"]$/g, ''))
+      .filter(Boolean);
+  }
+
+  const tools = [];
+  for (let i = keyIndex + 1; i < lines.length; i += 1) {
+    const line = lines[i];
+    const item = line.match(/^\s*-\s+(.+?)\s*$/);
+    if (item) {
+      tools.push(item[1].replace(/^['"]|['"]$/g, ''));
+      continue;
+    }
+    // The first line that is neither a list item nor blank ends the block —
+    // the next frontmatter key, or the closing `---`.
+    if (line.trim() === '') continue;
+    break;
+  }
+  return tools;
+}
+
+/**
+ * List command stems under `dir`, sorted.
+ *
+ * @param {string} dir  absolute path to the commands directory
+ * @returns {{ stem: string, file: string }[]}
+ */
+function listCommands(dir) {
+  let entries;
+  try {
+    entries = fs.readdirSync(dir, { withFileTypes: true });
+  } catch {
+    return [];
+  }
+  return entries
+    .filter((e) => e.isFile() && e.name.endsWith('.md'))
+    .map((e) => ({ stem: e.name.replace(/\.md$/, ''), file: path.join(dir, e.name) }))
+    .sort((a, b) => a.stem.localeCompare(b.stem));
+}
+
+/**
+ * Evaluate the corpus.
+ *
+ * Reports two independent failure classes, because an exemption list that
+ * can only ever grow rots into a list of things nobody re-examined:
+ *
+ *   - `violations`: declares Bash, omits Grep, not exempt.
+ *   - `staleExemptions`: on the list but no longer needs to be — either the
+ *     command is gone, or it no longer declares Bash without Grep. Removing
+ *     the entry is then a one-line diff, and the next omission in that
+ *     command is caught rather than silently pre-forgiven.
+ *
+ * @param {string} [root]  repo-relative commands directory
+ * @returns {{ scanned: number, violations: {stem: string, tools: string[]}[], staleExemptions: {stem: string, reason: string}[] }}
+ */
+function scan(root = DEFAULT_ROOT) {
+  const abs = path.isAbsolute(root) ? root : path.join(ROOT, root);
+  const commands = listCommands(abs);
+  const violations = [];
+  const seen = new Set();
+
+  for (const { stem, file } of commands) {
+    const tools = parseAllowedTools(fs.readFileSync(file, 'utf8'));
+    if (!tools) continue;
+    if (!tools.includes('Bash') || tools.includes('Grep')) continue;
+    seen.add(stem);
+    if (EXEMPT.has(stem)) continue;
+    violations.push({ stem, tools });
+  }
+
+  const present = new Set(commands.map((c) => c.stem));
+  const staleExemptions = [];
+  for (const [stem, reason] of EXEMPT) {
+    if (!present.has(stem)) {
+      staleExemptions.push({ stem, reason: `no such command (${reason})` });
+    } else if (!seen.has(stem)) {
+      staleExemptions.push({ stem, reason: `no longer declares Bash without Grep (${reason})` });
+    }
+  }
+
+  return { scanned: commands.length, violations, staleExemptions };
+}
+
+function main() {
+  const root = process.env.GSD_LINT_ALLOWED_TOOLS_ROOT || DEFAULT_ROOT;
+  const { scanned, violations, staleExemptions } = scan(root);
+
+  if (violations.length > 0 || staleExemptions.length > 0) {
+    const parts = [];
+    if (violations.length > 0) {
+      parts.push(
+        'lint-allowed-tools-parity: these commands declare `Bash` but not `Grep` (#4394).\n' +
+          'A command that can shell out but cannot Grep reaches for `Bash` + `grep` instead —\n' +
+          'slower, unstructured, and a portability hazard on hosts without GNU grep. Add `Grep`\n' +
+          'to the frontmatter, or add the command to EXEMPT in this script with a reason:\n' +
+          violations.map((v) => `  ${root}/${v.stem}.md  [${v.tools.join(', ')}]`).join('\n'),
+      );
+    }
+    if (staleExemptions.length > 0) {
+      parts.push(
+        'lint-allowed-tools-parity: these EXEMPT entries are stale — delete them so the next\n' +
+          'omission in those commands is caught rather than silently pre-forgiven:\n' +
+          staleExemptions.map((s) => `  ${s.stem}: ${s.reason}`).join('\n'),
+      );
+    }
+    throw new ExitError(1, parts.join('\n\n'));
+  }
+
+  console.log(
+    `ok lint-allowed-tools-parity: ${scanned} command(s) checked, ${EXEMPT.size} exemption(s) all still needed`,
+  );
+}
+
+module.exports = { parseAllowedTools, scan, EXEMPT, DEFAULT_ROOT };
+
+if (require.main === module) runMain(main);
diff --git a/tests/lint-allowed-tools-parity.test.cjs b/tests/lint-allowed-tools-parity.test.cjs
new file mode 100644
index 000000000..30082403b
--- /dev/null
+++ b/tests/lint-allowed-tools-parity.test.cjs
@@ -0,0 +1,157 @@
+'use strict';
+
+// #4394: unit tests for the allowed-tools parity lint. The rule reads command
+// frontmatter, so every arm below drives it against a synthetic commands
+// directory rather than the live corpus — a test that asserted "the real tree
+// is clean" would say nothing about whether the rule can DETECT anything, and
+// that is exactly the failure mode this lint exists to close (the pre-existing
+// generated-sync check compares the two trees only to each other, so a shared
+// omission was invisible to it).
+
+const { test, describe } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const os = require('node:os');
+const path = require('node:path');
+
+const { parseAllowedTools, scan, EXEMPT } = require('../scripts/lint-allowed-tools-parity.cjs');
+const { cleanup } = require('./helpers.cjs');
+
+/** Write a synthetic commands dir; returns its absolute path. */
+function fixture(commands) {
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-4394-'));
+  for (const [stem, tools] of Object.entries(commands)) {
+    const frontmatter = tools === null
+      ? ['---', `name: gsd:${stem}`, '---', '']
+      : ['---', `name: gsd:${stem}`, 'allowed-tools:', ...tools.map((t) => `  - ${t}`), 'requires: []', '---', ''];
+    fs.writeFileSync(path.join(dir, `${stem}.md`), `${frontmatter.join('\n')}\nbody\n`);
+  }
+  return dir;
+}
+
+describe('#4394 parseAllowedTools', () => {
+  test('reads a YAML block sequence', () => {
+    const text = ['---', 'name: gsd:x', 'allowed-tools:', '  - Read', '  - Bash', 'requires: []', '---'].join('\n');
+    assert.deepEqual(parseAllowedTools(text), ['Read', 'Bash']);
+  });
+
+  test('stops at the next frontmatter key, not at the end of the file', () => {
+    // A body bullet list must not be swallowed into the tool set.
+    const text = [
+      '---', 'allowed-tools:', '  - Read', 'requires: [review]', '---', '', 'Steps:', '  - Bash', '',
+    ].join('\n');
+    assert.deepEqual(parseAllowedTools(text), ['Read']);
+  });
+
+  test('reads an inline flow sequence and a bare inline list', () => {
+    assert.deepEqual(parseAllowedTools('allowed-tools: [Read, Bash]'), ['Read', 'Bash']);
+    assert.deepEqual(parseAllowedTools('allowed-tools: Read, Bash'), ['Read', 'Bash']);
+  });
+
+  test('strips quotes around tool names', () => {
+    assert.deepEqual(parseAllowedTools("allowed-tools: ['Read', \"Bash\"]"), ['Read', 'Bash']);
+  });
+
+  test('returns null when the key is absent', () => {
+    // Absent is NOT a violation: a command with no allowed-tools declares no
+    // Bash either, so the rule has nothing to say about it. Returning [] here
+    // would be indistinguishable from "declared, but empty".
+    assert.equal(parseAllowedTools('---\nname: gsd:x\n---\n'), null);
+  });
+});
+
+describe('#4394 scan — the rule detects, and only what it should', () => {
+  test('flags Bash without Grep', () => {
+    const dir = fixture({ offender: ['Read', 'Bash'] });
+    try {
+      const { violations } = scan(dir);
+      assert.deepEqual(violations.map((v) => v.stem), ['offender']);
+      // The message has to carry the declared set, or the fix is a guess.
+      assert.deepEqual(violations[0].tools, ['Read', 'Bash']);
+    } finally { cleanup(dir); }
+  });
+
+  test('accepts Bash WITH Grep', () => {
+    const dir = fixture({ fine: ['Read', 'Bash', 'Grep'] });
+    try {
+      assert.deepEqual(scan(dir).violations, []);
+    } finally { cleanup(dir); }
+  });
+
+  test('ignores a command that declares no Bash', () => {
+    // The rule is about Bash standing in for a search the command cannot
+    // perform. No Bash, no substitution, nothing to say.
+    const dir = fixture({ reader: ['Read', 'Skill'] });
+    try {
+      assert.deepEqual(scan(dir).violations, []);
+    } finally { cleanup(dir); }
+  });
+
+  test('ignores a command with no allowed-tools key at all', () => {
+    const dir = fixture({ bare: null });
+    try {
+      assert.deepEqual(scan(dir).violations, []);
+    } finally { cleanup(dir); }
+  });
+
+  test('reports every offender, not just the first', () => {
+    const dir = fixture({ a: ['Bash'], b: ['Bash'], c: ['Bash', 'Grep'] });
+    try {
+      assert.deepEqual(scan(dir).violations.map((v) => v.stem), ['a', 'b']);
+    } finally { cleanup(dir); }
+  });
+});
+
+describe('#4394 scan — the exemption list cannot rot', () => {
+  // An exemption list that can only grow becomes a list of things nobody
+  // re-examined. These arms are what keep an exemption a real suppression
+  // rather than a comment.
+  const exemptStem = [...EXEMPT.keys()][0];
+
+  test('an exempt command that still needs its entry is silent', () => {
+    const dir = fixture({ [exemptStem]: ['Read', 'Write', 'Bash'] });
+    try {
+      const { violations, staleExemptions } = scan(dir);
+      assert.deepEqual(violations, []);
+      assert.deepEqual(staleExemptions, []);
+    } finally { cleanup(dir); }
+  });
+
+  test('an exempt command that gained Grep is reported as stale', () => {
+    const dir = fixture({ [exemptStem]: ['Read', 'Bash', 'Grep'] });
+    try {
+      const { staleExemptions } = scan(dir);
+      assert.deepEqual(staleExemptions.map((s) => s.stem), [exemptStem]);
+      assert.match(staleExemptions[0].reason, /no longer declares Bash without Grep/);
+    } finally { cleanup(dir); }
+  });
+
+  test('an exemption for a command that no longer exists is reported as stale', () => {
+    const dir = fixture({ unrelated: ['Read'] });
+    try {
+      const { staleExemptions } = scan(dir);
+      assert.deepEqual(staleExemptions.map((s) => s.stem), [exemptStem]);
+      assert.match(staleExemptions[0].reason, /no such command/);
+    } finally { cleanup(dir); }
+  });
+
+  test('every exemption carries a non-empty reason', () => {
+    // The reason is what makes changing the set reviewable. An entry without
+    // one is a suppression nobody can evaluate.
+    for (const [stem, reason] of EXEMPT) {
+      assert.equal(typeof reason, 'string', `${stem} must carry a reason`);
+      assert.ok(reason.trim().length > 10, `${stem}'s reason must say something: ${JSON.stringify(reason)}`);
+    }
+  });
+});
+
+describe('#4394 scan — against the live corpus', () => {
+  test('the exemption list has no stale entries on the real tree', () => {
+    // Kept separate from the violations count, which is deliberately NOT
+    // asserted here: the 21 commands #3085 identified are fixed by its own PR,
+    // and pinning a number would make this test a baseline that every such fix
+    // has to update. Staleness is different — it is a property of THIS
+    // script's list, and it is always this script's job to keep true.
+    assert.deepEqual(scan().staleExemptions, []);
+  });
+});