From f6835fc16b738dd87ca31610ca7bae2285724ae7 Mon Sep 17 00:00:00 2001
From: garrytan <garrytan@gmail.com>
Date: Fri, 16 Oct 2026 23:18:15 +0000
Subject: [PATCH] feat(approval-classes): gstack-approval-classes and
 ship-receipt citation enforcement (W2, WIP)

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>
(cherry picked from commit 847c7dae3dd5e49316733497a7b607869d51c28f)
---
 bin/gstack-approval-classes |  83 ++++++++++++
 bin/gstack-ship-receipt     |  34 ++++-
 docs/troubleshooting.md     |  65 ++++++++++
 lib/approval-citations.ts   | 204 +++++++++++++++++++++++++++++
 lib/approval-classes.ts     | 249 ++++++++++++++++++++++++++++++++++++
 lib/headless-artifacts.ts   |   3 +
 lib/result-codes.ts         |  26 ++++
 lib/ship-receipt.ts         |   4 +-
 8 files changed, 662 insertions(+), 6 deletions(-)
 create mode 100755 bin/gstack-approval-classes
 create mode 100644 lib/approval-citations.ts
 create mode 100644 lib/approval-classes.ts

diff --git a/bin/gstack-approval-classes b/bin/gstack-approval-classes
new file mode 100755
index 000000000..0ebf2b34e
--- /dev/null
+++ b/bin/gstack-approval-classes
@@ -0,0 +1,83 @@
+#!/usr/bin/env bun
+/**
+ * gstack-approval-classes — changes that need the owner's approval (field list 2, W2).
+ *
+ *   gstack-approval-classes [check] [--base <ref>] [--head <ref>] [--diff-base <sha>] [--json]
+ *   gstack-approval-classes init [--force]
+ *   gstack-approval-classes validate
+ *
+ * `check` reads the classes from the committed `origin/<base>` copy of
+ * .gstack/approval-classes.json (never the working tree) and the migration
+ * rule from the base's ship policy, scans the branch's changes since the
+ * merge base, and prints `APPROVAL_CLASS: <class> <file>:<line>` per hit, one
+ * `APPROVAL_SCOPE: <class>@<digest12>` per declared class with hits, and
+ * `APPROVAL_CLASSES: ok | found=<n> | none` last. Built-in detectors only
+ * report. Exit 0 ok or none, 1 found, 3 when the base file is invalid or the
+ * base is unresolvable. Enforcement is gstack-ship-receipt write
+ * (APPROVAL_CITATION_MISSING). Logic: lib/approval-classes.ts.
+ */
+import { spawnSync } from 'node:child_process';
+import * as fs from 'node:fs';
+import * as path from 'node:path';
+import { APPROVAL_CLASSES_PATH, exampleApprovalClassesJson, loadWorkingApprovalClasses, renderApprovalScan, runApprovalScan } from '../lib/approval-classes';
+import { EXIT, exitTableHelp } from '../lib/headless-artifacts';
+import { resultLine } from '../lib/result-codes';
+import { resolveBaseBranch } from '../lib/ship-policy';
+
+const HELP = `gstack-approval-classes — changes that need the owner's approval (docs/ship-policy.md#approval-classes)
+
+  check [--base <ref>] [--head <ref>] [--diff-base <sha>] [--json]
+        changes since the merge base with origin/<base> (default origin/HEAD's branch), at --head or the
+        working tree; classes come only from the committed ${APPROVAL_CLASSES_PATH} on origin/<base>
+  init [--force]        write an example ${APPROVAL_CLASSES_PATH}
+  validate              schema and containment check of the working-tree file (before you commit it)
+
+A declared class with hits needs a line in the PR body that gstack-ship-receipt write can resolve:
+  Approved by <owner> <YYYY-MM-DD> via <plan sha|comment or review URL|ref> [for <class>@<digest12>]
+
+${exitTableHelp()}`;
+
+function flag(args: string[], name: string): string | undefined {
+  const i = args.indexOf(name);
+  return i >= 0 ? args[i + 1] : undefined;
+}
+
+function main(argv: string[]): number {
+  if (argv.includes('--help') || argv.includes('-h')) { process.stdout.write(HELP + '\n'); return EXIT.ok; }
+  const cmd = argv[0] && !argv[0].startsWith('--') ? argv[0] : 'check';
+  const rest = cmd === argv[0] ? argv.slice(1) : argv;
+  const root = spawnSync('git', ['rev-parse', '--show-toplevel'], { encoding: 'utf8', timeout: 15_000 });
+  if (root.status !== 0) { process.stderr.write('gstack-approval-classes: not inside a git repository\n'); return EXIT.usage; }
+  const repoRoot = root.stdout.trim();
+  const file = path.join(repoRoot, APPROVAL_CLASSES_PATH);
+
+  if (cmd === 'init') {
+    if (fs.existsSync(file) && !rest.includes('--force')) { process.stderr.write(`gstack-approval-classes: ${APPROVAL_CLASSES_PATH} exists (pass --force to overwrite)\n`); return EXIT.refused; }
+    fs.mkdirSync(path.dirname(file), { recursive: true });
+    fs.writeFileSync(file, exampleApprovalClassesJson());
+    process.stdout.write(`APPROVAL_CLASSES_INIT: ${APPROVAL_CLASSES_PATH} (edit, commit and merge it; check reads only the base copy)\n`);
+    return EXIT.ok;
+  }
+  if (cmd === 'validate') {
+    const load = loadWorkingApprovalClasses(repoRoot);
+    if ('absent' in load) { process.stdout.write(`APPROVAL_CLASSES: none (no ${APPROVAL_CLASSES_PATH})\n`); return EXIT.ok; }
+    if ('errors' in load) { for (const e of load.errors) process.stderr.write(resultLine('gstack-approval-classes validate', 'APPROVAL_CLASSES_INVALID', `${e.message} at ${e.path || '<root>'}`) + '\n'); return EXIT.refused; }
+    if ('unavailable' in load || !load.config) return EXIT.fail;
+    process.stdout.write(`APPROVAL_CLASSES_VALID: ${APPROVAL_CLASSES_PATH} classes=${load.config.classes.length}\n`);
+    return EXIT.ok;
+  }
+  if (cmd !== 'check') { process.stderr.write(`gstack-approval-classes: unknown command ${cmd}\n${HELP}\n`); return EXIT.usage; }
+
+  const json = rest.includes('--json');
+  const base = resolveBaseBranch(repoRoot, flag(rest, '--base'));
+  const outcome = runApprovalScan({ repoRoot, base, head: flag(rest, '--head'), diffBase: flag(rest, '--diff-base') });
+  if ('unavailable' in outcome) { process.stderr.write(resultLine('gstack-approval-classes', 'APPROVAL_SOURCE_UNAVAILABLE', `${outcome.unavailable}; classes are read only from the base, so nothing was checked`) + '\n'); return EXIT.refused; }
+  if ('errors' in outcome) { for (const e of outcome.errors) process.stderr.write(resultLine('gstack-approval-classes', 'APPROVAL_CLASSES_INVALID', `${e.message} at ${e.path || '<root>'} (${outcome.source})`) + '\n'); return EXIT.refused; }
+  if ('error' in outcome) { process.stderr.write(`gstack-approval-classes: ${outcome.error}\n`); return EXIT.usage; }
+  const { scan, absent } = outcome;
+  process.stdout.write(json ? JSON.stringify({ ...scan, absent }) + '\n' : renderApprovalScan(scan, absent));
+  if (scan.hits.length) { process.stderr.write(resultLine('gstack-approval-classes', 'APPROVAL_CLASS_FOUND', `${scan.scopes.map(s => s.token).join(', ')} need an Approved by line`) + '\n'); return EXIT.fail; }
+  return EXIT.ok;
+}
+
+process.exitCode = main(process.argv.slice(2));
diff --git a/bin/gstack-ship-receipt b/bin/gstack-ship-receipt
index f8441f1a7..e74a64a48 100755
--- a/bin/gstack-ship-receipt
+++ b/bin/gstack-ship-receipt
@@ -6,7 +6,8 @@
  *                             [--predecessor <sha>] [--gate <json|@file>] [--ci <json|@file>] [--spend-usd <n>]
  *                             [--session-kind <k>] [--artifacts-consumed <n>/<m>] [--run <id>] [--thread <id>]
  *                             [--receipt <tree-receipt.json>] [--policy <label>] [--preregistration <text>] [--history <text>]
- *                             [--pregate <pregate.json>] [--issues <json|@file>] [--out <file>] [--body <pr-body.md>] [--json]
+ *                             [--pregate <pregate.json>] [--issues <json|@file>] [--approval <line>]... [--approval-run <dir>]...
+ *                             [--out <file>] [--body <pr-body.md>] [--json]
  *   gstack-ship-receipt read --pr <n> [--repo <owner/repo>] [--json]
  *   gstack-ship-receipt read --body <file> [--json]
  *   gstack-ship-receipt census --repo <owner/repo> --since <tag|YYYY-MM-DD> [--cohort <file>] [--limit <n>] [--json]
@@ -24,6 +25,7 @@ import { resultLine, resultLineWithDocs } from '../lib/result-codes';
 import { versionAtRef } from '../lib/restamp';
 import { readPregateFile, verifyPregate } from '../lib/pregate/index';
 import { resolveBaseBranch } from '../lib/ship-policy';
+import { approvalForReceipt } from '../lib/approval-citations';
 import {
   computeCensus, extractReceipt, missingIssueLines, orderReceipt, placeReceiptFirst, receiptIssuesFrom, receiptSummaryLine, renderCensus, renderReceiptBlock,
   validateReceipt, type CensusPr,
@@ -41,7 +43,11 @@ write flags: --pr --head --base --version --gated-tree --predecessor --gate <jso
   --session-kind --artifacts-consumed <n>/<m> --run --thread --receipt <tree-receipt.json> --policy --preregistration
   --history --queue-mode --pregate <pregate.json> (C8: refused unless current, green and every requires-remote obligation
   carries a receipt: PREGATE_STALE / PREGATE_LANE_FAILED / PREGATE_INCOMPLETE / PREGATE_REMOTE_UNCLEARED) --issues <json|@file>
-  (C6: gstack-issue-links --out/--json; with --body, refused with ISSUE_LINKS_MISSING unless the body carries every Fixes/Refs/Flake/Related line) --out <file> --body <pr-body.md>. Defaults: head=HEAD, base=origin/HEAD's branch, version=the
+  (C6: gstack-issue-links --out/--json; with --body, refused with ISSUE_LINKS_MISSING unless the body carries every Fixes/Refs/Flake/Related line)
+  --approval <"Approved by <owner> <YYYY-MM-DD> via <ref> [for <class>@<digest12>]"> (repeatable; the --body file's lines count too)
+  --approval-run <autoplan run dir> (repeatable; resolves plan-sha citations) (W2: a class declared in origin/<base>'s
+  .gstack/approval-classes.json with hits needs a citation that resolves and binds to its effects: APPROVAL_CITATION_MISSING)
+  --out <file> --body <pr-body.md>. Defaults: head=HEAD, base=origin/HEAD's branch, version=the
   version source at HEAD, session_kind=$GSTACK_SESSION_KIND (gstack-session-kind), tree/gate_reuse/gated_tree/predecessor
   from --receipt when given.
 --json: JSON only on stdout.
@@ -51,6 +57,9 @@ function flag(args: string[], name: string): string | undefined {
   const i = args.indexOf(name);
   return i >= 0 ? args[i + 1] : undefined;
 }
+function flags(args: string[], name: string): string[] {
+  return args.flatMap((a, i) => (a === name && args[i + 1] !== undefined ? [args[i + 1]!] : []));
+}
 function jsonArg(raw: string | undefined): Record<string, unknown> | undefined {
   if (raw === undefined) return undefined;
   const text = raw.startsWith('@') ? fs.readFileSync(raw.slice(1), 'utf8') : raw;
@@ -92,19 +101,34 @@ function cmdWrite(rest: string[], json: boolean): number {
     const remote = read.file.requires_remote ?? [];
     pregate = { pregate: `${read.file.verdict ?? 'pass'} @${read.file.tree.slice(0, 12)} (${read.file.checks.length} checks, current for ${head.slice(0, 12)})`, requires_remote: remote.length ? remote.map(r => `${r.lane}: ${r.receipt}`) : undefined };
   }
+  const base = flag(rest, '--base') ?? resolveBaseBranch(repoRoot);
+  const bodyFile = flag(rest, '--body');
+  const bodyText = bodyFile && fs.existsSync(bodyFile) ? fs.readFileSync(bodyFile, 'utf8').replace(/```gstack-ship-receipt[\s\S]*?\n```/g, '') : '';
+  const approval = approvalForReceipt({ repoRoot, base, head, citationText: [bodyText, ...flags(rest, '--approval')].join('\n'), runDirs: flags(rest, '--approval-run') });
+  if (approval.kind === 'invalid') {
+    for (const line of approval.lines) process.stderr.write(resultLine('gstack-ship-receipt write', 'APPROVAL_CLASSES_INVALID', line) + '\n');
+    return EXIT.fail;
+  }
+  if (approval.kind === 'error') { process.stderr.write(`gstack-ship-receipt write: approval classes: ${approval.message}; nothing written\n`); return EXIT.fail; }
+  if (approval.kind === 'missing') {
+    for (const m of approval.missing) process.stderr.write(resultLine('gstack-ship-receipt write', 'APPROVAL_CITATION_MISSING', `${m.class} (${m.token}; effects in ${m.files.join(', ')}): ${m.reasons.join('; ')}`) + '\n');
+    process.stderr.write('gstack-ship-receipt write: nothing written\n');
+    return EXIT.fail;
+  }
+  if (approval.kind === 'ok' && approval.note) process.stderr.write(approval.note + '\n');
   let input: Partial<ShipReceipt>;
   try {
     const issuesFile = jsonArg(flag(rest, '--issues'));
     input = {
       schema_version: 1, pr: flag(rest, '--pr') !== undefined ? Number(flag(rest, '--pr')) : undefined, head,
-      version: flag(rest, '--version') ?? ('version' in atHead ? atHead.version : undefined), base: flag(rest, '--base') ?? resolveBaseBranch(repoRoot),
+      version: flag(rest, '--version') ?? ('version' in atHead ? atHead.version : undefined), base,
       gated_tree: flag(rest, '--gated-tree') ?? tree?.gated_tree, predecessor: flag(rest, '--predecessor') ?? tree?.predecessor?.recorded_head ?? undefined,
       tree: tree?.tree, gate_reuse: tree ? `${tree.gate_reuse} (${tree.gate_reuse_reason})` : undefined,
       gate: jsonArg(flag(rest, '--gate')), ci: jsonArg(flag(rest, '--ci')),
       spend_usd: flag(rest, '--spend-usd') !== undefined ? (Number.isFinite(Number(flag(rest, '--spend-usd'))) ? Number(flag(rest, '--spend-usd')) : flag(rest, '--spend-usd')) : undefined,
       session_kind: sessionKind, artifacts_consumed: flag(rest, '--artifacts-consumed'), run: flag(rest, '--run'), thread: flag(rest, '--thread'),
       policy: flag(rest, '--policy') ?? tree?.policy, queue_mode: flag(rest, '--queue-mode'), preregistration: flag(rest, '--preregistration'), history: flag(rest, '--history'),
-      ...pregate, issues: issuesFile ? receiptIssuesFrom(issuesFile) : undefined,
+      ...pregate, issues: issuesFile ? receiptIssuesFrom(issuesFile) : undefined, approval: approval.kind === 'ok' ? approval.approval : undefined,
     };
   } catch (e: any) { process.stderr.write(`gstack-ship-receipt write: ${e.message}\n`); return EXIT.usage; }
   if (input.pr !== undefined && !Number.isInteger(input.pr)) { process.stderr.write('gstack-ship-receipt write: --pr must be an integer\n'); return EXIT.usage; }
@@ -115,7 +139,7 @@ function cmdWrite(rest: string[], json: boolean): number {
     process.stderr.write('gstack-ship-receipt write: nothing written\n');
     return EXIT.fail;
   }
-  const body = flag(rest, '--body');
+  const body = bodyFile;
   const missing = body && receipt.issues ? missingIssueLines(fs.existsSync(body) ? fs.readFileSync(body, 'utf8') : '', receipt.issues) : [];
   if (missing.length) {
     process.stderr.write(resultLineWithDocs('gstack-ship-receipt write', 'ISSUE_LINKS_MISSING', `${body} lacks ${missing.map(l => JSON.stringify(l)).join(', ')}`) + '\n');
diff --git a/docs/troubleshooting.md b/docs/troubleshooting.md
index 1b1ba4ca8..d9c1bbc4a 100644
--- a/docs/troubleshooting.md
+++ b/docs/troubleshooting.md
@@ -3557,3 +3557,68 @@ an event or a poll with a deadline. When the bound is the contract, add
 `gstack-timing-ok: <reason>` in a comment on the line or the line above. Never
 raise a bound to make a flake pass; /investigate's flake playbook covers the
 diagnosis.
+
+<a id="approval-classes-invalid"></a>
+### `APPROVAL_CLASSES_INVALID`
+
+**Meaning.** The `.gstack/approval-classes.json` committed on the base branch
+(or, for `gstack-approval-classes validate`, the working-tree copy) is not
+valid JSON, has an unknown key, a class without a name or anything to match,
+or a glob that escapes the repository. `gstack-ship-receipt write` refuses
+rather than ship with the classes unchecked.
+
+**Fix.** Run `gstack-approval-classes validate`, correct the file, and merge
+it. See [Approval classes](ship-policy.md#approval-classes).
+
+<a id="approval-class-found"></a>
+### `APPROVAL_CLASS_FOUND`
+
+**Meaning.** `gstack-approval-classes check` found changes a declared class
+covers. Each `APPROVAL_CLASS:` line names the class and file:line, and each
+`APPROVAL_SCOPE: <class>@<digest12>` line is the token an approval binds to.
+Report-only lines from built-in detectors do not set this code.
+
+**Fix.** Ask the owner, then add
+`Approved by <owner> <YYYY-MM-DD> via <ref> for <class>@<digest12>` to the PR
+body. The token changes whenever an effect is added, removed or edited, so a
+later change needs a new approval.
+
+<a id="approval-citation-missing"></a>
+### `APPROVAL_CITATION_MISSING`
+
+**Meaning.** `gstack-ship-receipt write` found a declared approval class with
+no citation that both resolves and binds to the current effects, and wrote no
+receipt. The line lists every candidate citation and why it did not count:
+the plan's autoplan gate is not APPROVED, the comment is not by a ship-policy
+maintainer or not by the cited owner, the evidence names neither the scope
+token nor the class with every effect path (an approval of other work, or one
+given before an effect was added), or an unresolvable reference lacks a
+matching `for <class>@<digest12>` attestation.
+
+**Fix.** Cite the approval: a plan sha with `--approval-run <run dir>`, or the
+URL of a maintainer's comment or review that names the token. For evidence
+gstack cannot read (a thread code, a chat message), attest which scope it
+covers with `for <class>@<digest12>`; the receipt records it as
+`citation: unverified` for the coordinator.
+
+<a id="approval-source-unavailable"></a>
+### `APPROVAL_SOURCE_UNAVAILABLE`
+
+**Meaning.** `origin/<base>` does not resolve, so the committed approval
+classes cannot be read. `check` exits 3; `gstack-ship-receipt write`
+records `approval.status: unavailable` and prints `approval=unchecked`.
+
+**Fix.** `git fetch origin <base>` and rerun. The working-tree copy is never
+used.
+
+<a id="state-matrix-incomplete"></a>
+### `STATE_MATRIX_INCOMPLETE`
+
+**Meaning.** `gstack-state-matrix check` read the state-machines specialist's
+output and found a gap: a kind × owner action pair with no row, a row with no
+resulting row, a test reference that does not exist in the checkout, or an
+untested cell without a CRITICAL finding. A review whose matrix is incomplete
+has incomplete coverage, never a clean result.
+
+**Fix.** Rerun the state-machines specialist on the same diff and check its
+output again.
diff --git a/lib/approval-citations.ts b/lib/approval-citations.ts
new file mode 100644
index 000000000..63cf474fc
--- /dev/null
+++ b/lib/approval-citations.ts
@@ -0,0 +1,204 @@
+/**
+ * approval-citations — the `Approved by <owner> <YYYY-MM-DD> via <ref>`
+ * lines that let a change in a declared approval class ship (field list 2,
+ * W2; lib/approval-classes.ts finds the classes). A citation is resolved,
+ * never trusted as typed:
+ *
+ * - a plan sha (7-64 hex) must match the plan of an autoplan run passed with
+ *   `--approval-run <dir>` whose gate is APPROVED (status complete, the p1
+ *   decision answered and not reject/interrogate), with plan.md matching its
+ *   manifest hash;
+ * - a GitHub comment or review URL must be written by a ship-policy
+ *   maintainer whose login is the cited owner (a review requesting changes is
+ *   not an approval);
+ * - anything else, or a ref that cannot be read here, is `unverified`.
+ *
+ * Resolution alone is not enough: the evidence (the approved plan text or
+ * the comment body) must bind to the class's current effects, by carrying the
+ * scope token `<class>@<digest12>` or by naming the class and every effect
+ * path. An authentic approval of other work, or one given before an effect
+ * was added, does not bind. An unverified citation counts only as an explicit
+ * applicability attestation: `for <class>@<digest12>` on the line, matching
+ * the current scope, so a later effect change invalidates it.
+ * Caller: bin/gstack-ship-receipt write (APPROVAL_CITATION_MISSING).
+ */
+import { spawnSync } from 'node:child_process';
+import * as fs from 'node:fs';
+import * as path from 'node:path';
+import { runApprovalScan, type ApprovalHit, type ApprovalScope } from './approval-classes';
+import { sha256File } from './headless-artifacts';
+import { isUnavailable, loadPolicyFromBase } from './ship-policy';
+
+export interface Citation { raw: string; owner: string; date: string; ref: string; for: Array<{ class: string; digest?: string }> }
+export type Resolution =
+  | { state: 'resolved'; evidence: string; text: string }
+  | { state: 'rejected'; why: string }
+  | { state: 'unresolved'; why: string };
+export type GhRunner = (args: string[]) => { ok: boolean; out: string; err: string };
+export interface CitationContext { runDirs: string[]; maintainers: string[]; gh: GhRunner }
+
+const CLASS_REF = '[a-z][a-z0-9-]*(?:@[0-9a-f]{12,64})?';
+const CITATION_RE = new RegExp(`Approved by @?([A-Za-z0-9][\\w.-]*) (\\d{4}-\\d{2}-\\d{2}) via (\\S+)(?: for (${CLASS_REF}(?:,${CLASS_REF})*))?`, 'g');
+
+function validDate(d: string): boolean {
+  const t = Date.parse(`${d}T00:00:00Z`);
+  return !Number.isNaN(t) && new Date(t).toISOString().slice(0, 10) === d;
+}
+
+/** Every well-formed citation line in `text` (a PR body or --approval values); a bad calendar date is not a citation. */
+export function parseCitations(text: string): Citation[] {
+  const out: Citation[] = [];
+  for (const m of text.matchAll(CITATION_RE)) {
+    if (!validDate(m[2]!)) continue;
+    const ref = m[3]!.replace(/[.,;:)\]>]+$/, '');
+    const forList = (m[4] ?? '').split(',').filter(Boolean).map(entry => {
+      const [cls, digest] = entry.split('@');
+      return digest ? { class: cls!, digest } : { class: cls! };
+    });
+    out.push({ raw: m[0], owner: m[1]!.replace(/\.$/, ''), date: m[2]!, ref, for: forList });
+  }
+  return out;
+}
+
+function readJsonl(file: string): Array<Record<string, any>> {
+  if (!fs.existsSync(file)) return [];
+  return fs.readFileSync(file, 'utf8').split('\n').filter(Boolean).flatMap(l => { try { return [JSON.parse(l)]; } catch { return []; } });
+}
+
+function planGate(dir: string, run: Record<string, any>): Resolution {
+  const entry = run.artifacts?.['plan.md'];
+  const planFile = path.join(dir, entry?.path ?? 'plan.md');
+  if (!entry || !fs.existsSync(planFile) || sha256File(planFile) !== entry.sha256) return { state: 'rejected', why: `run ${run.run}: plan.md does not match its manifest hash` };
+  const gate = run.gate ?? {};
+  const rev = gate.gate_rev ?? run.gate_rev;
+  const p1 = readJsonl(path.join(dir, 'decisions.jsonl')).find(d => d.label === 'P1' && d.gate_rev === rev);
+  const approved = run.status === 'complete' && typeof gate.plan === 'string' && !['c', 'e'].includes(gate.plan) && p1 && p1.chosen === gate.plan && p1.status !== 'pending';
+  if (!approved) return { state: 'rejected', why: `run ${run.run} holds this plan but its gate is not APPROVED (status ${run.status}, p1 ${p1?.chosen ?? 'unanswered'})` };
+  return { state: 'resolved', evidence: `plan ${run.run} gate_rev=${rev} p1=${gate.plan} answered_by=${gate.answered_by ?? p1.answered_by ?? 'unrecorded'}`, text: fs.readFileSync(planFile, 'utf8') };
+}
+
+/** A plan sha: the plan.md (or reviewed plan) hash of an approved autoplan run among `runDirs`. */
+export function resolvePlan(ref: string, runDirs: string[]): Resolution {
+  const want = ref.toLowerCase();
+  let rejected: Resolution | undefined;
+  for (const dir of runDirs) {
+    let run: Record<string, any>;
+    try { run = JSON.parse(fs.readFileSync(path.join(dir, 'run.json'), 'utf8')); } catch { continue; }
+    const hashes = [run.artifacts?.['plan.md']?.sha256, run.plan_reality?.plan_sha256].filter((h): h is string => typeof h === 'string');
+    if (!hashes.some(h => h.toLowerCase().startsWith(want))) continue;
+    const r = planGate(dir, run);
+    if (r.state === 'resolved') return r;
+    rejected = r;
+  }
+  return rejected ?? { state: 'unresolved', why: runDirs.length ? `no --approval-run directory holds a plan with sha ${ref}` : `plan sha ${ref}: pass the autoplan run with --approval-run <dir>` };
+}
+
+const GH_URL = /^https:\/\/github\.com\/([\w.-]+)\/([\w.-]+)\/(?:pull|issues)\/(\d+)#(?:issuecomment-(\d+)|pullrequestreview-(\d+)|discussion_r(\d+))$/;
+
+/** A comment or review URL: authored by a ship-policy maintainer whose login is the cited owner. */
+export function resolveGithub(c: Citation, ctx: CitationContext): Resolution {
+  const m = GH_URL.exec(c.ref)!;
+  const [, owner, repo, num, issueComment, review, discussion] = m;
+  const api = issueComment ? `repos/${owner}/${repo}/issues/comments/${issueComment}`
+    : review ? `repos/${owner}/${repo}/pulls/${num}/reviews/${review}`
+    : `repos/${owner}/${repo}/pulls/comments/${discussion}`;
+  const r = ctx.gh(['api', api]);
+  if (!r.ok) return { state: 'unresolved', why: `gh api ${api} failed: ${r.err.split('\n')[0] || 'no output'}` };
+  let body: Record<string, any>;
+  try { body = JSON.parse(r.out); } catch { return { state: 'unresolved', why: `gh api ${api} returned no JSON` }; }
+  const login = String(body.user?.login ?? '');
+  if (!ctx.maintainers.length) return { state: 'unresolved', why: 'the base ship policy lists no maintainers, so the author cannot be classified' };
+  if (!ctx.maintainers.some(x => x.toLowerCase() === login.toLowerCase())) return { state: 'rejected', why: `${c.ref} is by ${login || 'an unknown author'}, not a ship-policy maintainer` };
+  if (login.toLowerCase() !== c.owner.toLowerCase()) return { state: 'rejected', why: `the citation names ${c.owner} but ${c.ref} is by ${login}` };
+  if (review && body.state === 'CHANGES_REQUESTED') return { state: 'rejected', why: `${c.ref} requests changes; it is not an approval` };
+  return { state: 'resolved', evidence: `${review ? 'review' : 'comment'} by ${login}`, text: String(body.body ?? '') };
+}
+
+export function resolveCitation(c: Citation, ctx: CitationContext): Resolution {
+  if (/^[0-9a-f]{7,64}$/i.test(c.ref)) return resolvePlan(c.ref, ctx.runDirs);
+  if (GH_URL.test(c.ref)) return resolveGithub(c, ctx);
+  return { state: 'unresolved', why: `${c.ref} is neither a plan sha nor a GitHub comment or review URL` };
+}
+
+/** How the evidence names this exact scope: the token, or the class plus every effect path; null when it does not. */
+export function binding(text: string, scope: ApprovalScope): 'token' | 'paths' | null {
+  const lower = text.toLowerCase();
+  if (lower.includes(scope.token.toLowerCase())) return 'token';
+  const named = new RegExp(`(^|[^a-z0-9-])${scope.class}([^a-z0-9-]|$)`).test(lower);
+  return named && scope.files.every(f => text.includes(f)) ? 'paths' : null;
+}
+
+export interface ApprovalRecord {
+  class: string; scope: string; effects: string[]; citation: 'verified' | 'unverified';
+  approved_by: string; date: string; via: string; binding: 'token' | 'paths' | 'attested'; evidence: string;
+}
+export interface MissingApproval { class: string; token: string; files: string[]; reasons: string[] }
+
+function judge(c: Citation, scope: ApprovalScope, res: Resolution): ApprovalRecord | string {
+  const base = { class: scope.class, scope: scope.token, effects: scope.hits, approved_by: c.owner, date: c.date, via: c.ref };
+  if (res.state === 'rejected') return `${c.ref}: ${res.why}`;
+  if (res.state === 'resolved') {
+    const how = binding(res.text, scope);
+    if (how) return { ...base, citation: 'verified', binding: how, evidence: res.evidence };
+    return `${c.ref}: ${res.evidence} names neither ${scope.token} nor ${scope.class} with every effect path (${scope.files.join(', ')}); an approval of other work, or one given before these effects, does not cover them`;
+  }
+  const attested = c.for.find(f => f.class === scope.class);
+  if (attested?.digest && scope.digest.startsWith(attested.digest)) return { ...base, citation: 'unverified', binding: 'attested', evidence: `unresolved: ${res.why}` };
+  if (attested?.digest) return `${c.ref}: attested for ${scope.class}@${attested.digest.slice(0, 12)} but the effects are now ${scope.token} (changed since the attestation)`;
+  return `${c.ref}: unresolved (${res.why}); an unverified citation must attest "for ${scope.token}"`;
+}
+
+/** One record per scope: a verified citation first, else an attested unverified one; otherwise the scope is missing, with every candidate's reason. */
+export function evaluateApprovals(scopes: ApprovalScope[], citations: Citation[], ctx: CitationContext): { records: ApprovalRecord[]; missing: MissingApproval[] } {
+  const cache = new Map<string, Resolution>();
+  const resolve = (c: Citation) => { const key = `${c.ref}\0${c.owner}`; if (!cache.has(key)) cache.set(key, resolveCitation(c, ctx)); return cache.get(key)!; };
+  const records: ApprovalRecord[] = [];
+  const missing: MissingApproval[] = [];
+  for (const scope of scopes) {
+    const candidates = citations.filter(c => !c.for.length || c.for.some(f => f.class === scope.class));
+    const judged = candidates.map(c => judge(c, scope, resolve(c)));
+    const pick = judged.find((j): j is ApprovalRecord => typeof j !== 'string' && j.citation === 'verified') ?? judged.find((j): j is ApprovalRecord => typeof j !== 'string');
+    if (pick) records.push(pick);
+    else missing.push({ class: scope.class, token: scope.token, files: scope.files, reasons: judged.length ? judged as string[] : ['no "Approved by" line names this class or applies to every class'] });
+  }
+  return { records, missing };
+}
+
+export function defaultGh(args: string[]): { ok: boolean; out: string; err: string } {
+  const r = spawnSync('gh', args, { encoding: 'utf8', timeout: 60_000, maxBuffer: 16 * 1024 * 1024 });
+  return { ok: r.status === 0, out: r.stdout ?? '', err: (r.stderr ?? '').trim() };
+}
+
+export interface ReceiptApprovalRequest { repoRoot: string; base: string; head: string; citationText: string; runDirs: string[]; gh?: GhRunner }
+export type ReceiptApproval =
+  | { kind: 'skip' }
+  | { kind: 'ok'; approval: Record<string, unknown>; note?: string }
+  | { kind: 'invalid'; lines: string[] }
+  | { kind: 'error'; message: string }
+  | { kind: 'missing'; missing: MissingApproval[] };
+
+const reportOnly = (hits: ApprovalHit[]) => hits.map(h => `${h.class} ${h.file}:${h.line} (${h.text})`);
+
+/** The receipt's approval object, or the refusal: classes from origin/<base>, effects at `head`, citations from the body and --approval. */
+export function approvalForReceipt(req: ReceiptApprovalRequest): ReceiptApproval {
+  const outcome = runApprovalScan({ repoRoot: req.repoRoot, base: req.base, head: req.head });
+  if ('unavailable' in outcome) return { kind: 'ok', approval: { source: outcome.source, status: 'unavailable', detail: outcome.unavailable, classes: [] }, note: `APPROVAL_CLASSES: unavailable (${outcome.unavailable}); approval classes were not checked` };
+  if ('errors' in outcome) return { kind: 'invalid', lines: outcome.errors.map(e => `${e.message} at ${e.path || '<root>'} (${outcome.source})`) };
+  if ('error' in outcome) return { kind: 'error', message: outcome.error };
+  const { scan, absent } = outcome;
+  if (absent && !scan.report_only.length) return { kind: 'skip' };
+  const policy = loadPolicyFromBase(req.repoRoot, req.base);
+  const maintainers = isUnavailable(policy) ? [] : policy.policy.maintainers;
+  const { records, missing } = evaluateApprovals(scan.scopes, parseCitations(req.citationText), { runDirs: req.runDirs, maintainers, gh: req.gh ?? defaultGh });
+  if (missing.length) return { kind: 'missing', missing };
+  return { kind: 'ok', approval: { source: scan.source, status: 'checked', classes: records, ...(scan.report_only.length ? { report_only: reportOnly(scan.report_only) } : {}) } };
+}
+
+/** The SHIP_RECEIPT summary token: verified, unverified:<classes>, none or unchecked. */
+export function approvalSummary(approval: Record<string, any>): string {
+  if (approval.status === 'unavailable') return 'unchecked';
+  const classes = (approval.classes ?? []) as ApprovalRecord[];
+  if (!classes.length) return 'none';
+  const unverified = classes.filter(c => c.citation === 'unverified').map(c => c.class);
+  return unverified.length ? `unverified:${unverified.join(',')}` : 'verified';
+}
diff --git a/lib/approval-classes.ts b/lib/approval-classes.ts
new file mode 100644
index 000000000..4b7847039
--- /dev/null
+++ b/lib/approval-classes.ts
@@ -0,0 +1,249 @@
+/**
+ * approval-classes — changes a repository says need the owner's approval
+ * (field list 2, W2). `.gstack/approval-classes.json`, read only from the
+ * committed copy on `origin/<base>` so a branch cannot declare or drop its
+ * own classes, lists named classes; each matches changed files by `paths`
+ * globs, added lines by literal `patterns`, and the ship policy's
+ * `migrations` files when `migrations: true`, minus its `allowed_paths`.
+ *
+ * Every declared class with hits gets a scope: the sorted effects (a path hit
+ * is the file and its blob at the scanned head; a pattern hit is the file and
+ * the added line's text) and a digest over them, printed as the token
+ * `<class>@<digest12>`. An approval citation binds to that token (or to the
+ * class name plus every effect path), so an approval for other work, or one
+ * given before an effect was added, does not cover the change
+ * (lib/approval-citations.ts). Built-in detectors (the ship policy's
+ * migration files when no declared class claims them) only report.
+ * Callers: bin/gstack-approval-classes, bin/gstack-ship-receipt.
+ */
+import { createHash } from 'node:crypto';
+import { spawnSync } from 'node:child_process';
+import * as fs from 'node:fs';
+import * as path from 'node:path';
+import { addedLines } from './banned-terms';
+import type { ResultCodeName } from './result-codes';
+import { assertInsideRoot, containedRelative, globToRegExp, isUnavailable, loadPolicyFromBase, matchesAny } from './ship-policy';
+
+export const APPROVAL_CLASSES_PATH = '.gstack/approval-classes.json';
+export const APPROVAL_CLASSES_SCHEMA = 'https://github.com/garrytan/gstack/docs/ship-policy.md#approval-classes';
+const NAME_RE = /^[a-z][a-z0-9-]{0,39}$/;
+const MAX_CLASSES = 32;
+const MAX_LIST = 64;
+const MAX_PATTERN = 200;
+const CLASS_KEYS = ['name', 'description', 'paths', 'patterns', 'allowed_paths', 'migrations'];
+
+export interface ApprovalClass { name: string; description?: string; paths?: string[]; patterns?: string[]; allowed_paths?: string[]; migrations?: boolean }
+export interface ApprovalClassesConfig { $schema?: string; classes: ApprovalClass[] }
+export interface ApprovalClassesError { code: ResultCodeName; path: string; message: string }
+export interface ApprovalHit { class: string; file: string; line: number; via: 'path' | 'pattern' | 'migration'; text: string; declared: boolean; effect: string }
+export interface ApprovalScope { class: string; digest: string; token: string; effects: string[]; files: string[]; hits: string[] }
+export interface ApprovalScan { source: string; classes: number; hits: ApprovalHit[]; report_only: ApprovalHit[]; scopes: ApprovalScope[] }
+export interface MigrationRule { dir: string; id: RegExp }
+
+export function exampleApprovalClassesJson(): string {
+  return JSON.stringify({
+    $schema: APPROVAL_CLASSES_SCHEMA,
+    classes: [
+      { name: 'upgrade-data-rewrite', description: 'a migration that rewrites existing rows when a user upgrades', migrations: true },
+      { name: 'trust-visibility', description: 'who can see or act on data', paths: ['src/auth/**', 'src/visibility/**'], patterns: ['visibility:'], allowed_paths: ['test/**'] },
+      { name: 'data-repair', description: 'a command that rewrites user data; explicit and preview-first, never run at upgrade', paths: ['src/commands/repair/**'] },
+      { name: 'default-change', description: 'a default that changes behavior for existing users', patterns: ['DEFAULT_'], allowed_paths: ['test/**', 'docs/**'] },
+    ],
+  }, null, 2) + '\n';
+}
+
+function listErrors(at: string, value: unknown, kind: 'glob' | 'pattern', errors: ApprovalClassesError[]): void {
+  if (!Array.isArray(value)) { errors.push({ code: 'APPROVAL_CLASSES_INVALID', path: at, message: `must be an array of ${kind}s` }); return; }
+  if (value.length > MAX_LIST) errors.push({ code: 'APPROVAL_CLASSES_INVALID', path: at, message: `more than ${MAX_LIST} entries` });
+  value.forEach((v, i) => {
+    let why: string | null = null;
+    if (typeof v !== 'string' || !v.trim()) why = 'must be a non-empty string';
+    else if (kind === 'pattern') why = v.length > MAX_PATTERN ? `longer than ${MAX_PATTERN} characters` : /[\0\r\n]/.test(v) ? 'contains a control character' : null;
+    else {
+      why = containedRelative(v);
+      if (!why) try { globToRegExp(v); } catch (e: any) { why = e.message; }
+    }
+    if (why) errors.push({ code: 'APPROVAL_CLASSES_INVALID', path: `${at}[${i}]`, message: `${JSON.stringify(v)} ${why}` });
+  });
+}
+
+function classErrors(c: unknown, at: string, seen: Set<string>, errors: ApprovalClassesError[]): void {
+  if (!c || typeof c !== 'object' || Array.isArray(c)) { errors.push({ code: 'APPROVAL_CLASSES_INVALID', path: at, message: 'must be an object' }); return; }
+  const cls = c as Record<string, unknown>;
+  for (const key of Object.keys(cls)) if (!CLASS_KEYS.includes(key)) errors.push({ code: 'APPROVAL_CLASSES_INVALID', path: `${at}.${key}`, message: `unknown key; valid keys: ${CLASS_KEYS.join(', ')}` });
+  if (typeof cls.name !== 'string' || !NAME_RE.test(cls.name)) errors.push({ code: 'APPROVAL_CLASSES_INVALID', path: `${at}.name`, message: 'must be lowercase letters, digits and dashes (1-40 characters, starting with a letter)' });
+  else if (seen.has(cls.name)) errors.push({ code: 'APPROVAL_CLASSES_INVALID', path: `${at}.name`, message: `duplicate class ${cls.name}` });
+  else seen.add(cls.name);
+  if (cls.description !== undefined && (typeof cls.description !== 'string' || cls.description.length > MAX_PATTERN)) errors.push({ code: 'APPROVAL_CLASSES_INVALID', path: `${at}.description`, message: `must be a string of at most ${MAX_PATTERN} characters` });
+  if (cls.migrations !== undefined && typeof cls.migrations !== 'boolean') errors.push({ code: 'APPROVAL_CLASSES_INVALID', path: `${at}.migrations`, message: 'must be true or false' });
+  if (cls.paths !== undefined) listErrors(`${at}.paths`, cls.paths, 'glob', errors);
+  if (cls.allowed_paths !== undefined) listErrors(`${at}.allowed_paths`, cls.allowed_paths, 'glob', errors);
+  if (cls.patterns !== undefined) listErrors(`${at}.patterns`, cls.patterns, 'pattern', errors);
+  const matches = (Array.isArray(cls.paths) && cls.paths.length > 0) || (Array.isArray(cls.patterns) && cls.patterns.length > 0) || cls.migrations === true;
+  if (!matches) errors.push({ code: 'APPROVAL_CLASSES_INVALID', path: at, message: 'matches nothing: give paths, patterns or migrations: true' });
+}
+
+/** Schema and containment: a non-empty `classes` list of uniquely named classes, each with something to match. Unknown keys are errors. */
+export function validateApprovalClasses(raw: unknown): ApprovalClassesError[] {
+  const errors: ApprovalClassesError[] = [];
+  if (!raw || typeof raw !== 'object' || Array.isArray(raw)) return [{ code: 'APPROVAL_CLASSES_INVALID', path: '', message: 'must be a JSON object' }];
+  const obj = raw as Record<string, unknown>;
+  for (const key of Object.keys(obj)) if (key !== '$schema' && key !== 'classes') errors.push({ code: 'APPROVAL_CLASSES_INVALID', path: key, message: 'unknown key; valid keys: classes' });
+  if (!Array.isArray(obj.classes) || obj.classes.length === 0) return [...errors, { code: 'APPROVAL_CLASSES_INVALID', path: 'classes', message: 'must be a non-empty array' }];
+  if (obj.classes.length > MAX_CLASSES) errors.push({ code: 'APPROVAL_CLASSES_INVALID', path: 'classes', message: `more than ${MAX_CLASSES} classes` });
+  const seen = new Set<string>();
+  obj.classes.forEach((c, i) => classErrors(c, `classes[${i}]`, seen, errors));
+  return errors;
+}
+
+export type ApprovalLoad =
+  | { config: ApprovalClassesConfig; source: string }
+  | { config: null; source: string; errors: ApprovalClassesError[] }
+  | { config: null; source: string; absent: true }
+  | { config: null; source: string; unavailable: string };
+
+function git(repoRoot: string, args: string[], timeout = 30_000): { ok: boolean; out: string } {
+  const r = spawnSync('git', args, { cwd: repoRoot, encoding: 'utf8', timeout, maxBuffer: 256 * 1024 * 1024 });
+  return { ok: r.status === 0, out: r.stdout ?? '' };
+}
+
+function parseConfig(text: string, source: string): ApprovalLoad {
+  let parsed: unknown;
+  try { parsed = JSON.parse(text); } catch (e: any) { return { config: null, source, errors: [{ code: 'APPROVAL_CLASSES_INVALID', path: '', message: `not valid JSON: ${e.message}` }] }; }
+  const errors = validateApprovalClasses(parsed);
+  return errors.length ? { config: null, source, errors } : { config: parsed as ApprovalClassesConfig, source };
+}
+
+/** `origin/<base>` for a branch name; a leading `origin/` is not doubled. */
+export function baseRef(base: string): string {
+  return `origin/${base.replace(/^origin\//, '')}`;
+}
+
+/** The committed copy on `origin/<base>`; never the working tree. An unresolvable base is `unavailable`, never a silent pass. */
+export function loadApprovalClasses(repoRoot: string, base: string): ApprovalLoad {
+  const ref = baseRef(base);
+  const sha = git(repoRoot, ['rev-parse', '--verify', '--quiet', `${ref}^{commit}`]);
+  if (!sha.ok || !sha.out.trim()) return { config: null, source: `${ref}:${APPROVAL_CLASSES_PATH}`, unavailable: `${ref} is not a resolvable commit` };
+  const commit = sha.out.trim();
+  const source = `${ref}@${commit.slice(0, 12)}:${APPROVAL_CLASSES_PATH}`;
+  if (!git(repoRoot, ['cat-file', '-e', `${commit}:${APPROVAL_CLASSES_PATH}`]).ok) return { config: null, source, absent: true };
+  const show = git(repoRoot, ['show', `${commit}:${APPROVAL_CLASSES_PATH}`]);
+  return show.ok ? parseConfig(show.out, source) : { config: null, source, errors: [{ code: 'APPROVAL_CLASSES_INVALID', path: '', message: 'unreadable' }] };
+}
+
+/** The working-tree file, for `validate` while editing it (enforcement never reads it). */
+export function loadWorkingApprovalClasses(repoRoot: string): ApprovalLoad {
+  const escape = assertInsideRoot(repoRoot, APPROVAL_CLASSES_PATH);
+  if (escape) return { config: null, source: APPROVAL_CLASSES_PATH, errors: [{ code: 'APPROVAL_CLASSES_INVALID', path: APPROVAL_CLASSES_PATH, message: escape }] };
+  const file = path.join(repoRoot, APPROVAL_CLASSES_PATH);
+  if (!fs.existsSync(file)) return { config: null, source: APPROVAL_CLASSES_PATH, absent: true };
+  return parseConfig(fs.readFileSync(file, 'utf8'), APPROVAL_CLASSES_PATH);
+}
+
+/** The ship policy's migration rule on the same reviewed base, or null. */
+export function baseMigrationRule(repoRoot: string, base: string): MigrationRule | null {
+  const load = loadPolicyFromBase(repoRoot, base);
+  if (isUnavailable(load) || load.errors.length || !load.policy.migrations) return null;
+  return { dir: load.policy.migrations.dir.replace(/\/+$/, ''), id: new RegExp(load.policy.migrations.id) };
+}
+
+export interface ChangedFile { file: string; status: string; blob: string; added: Array<{ line: number; text: string }> }
+
+/** Files changed between `diffBase` and `head` (the working tree when `head` is omitted), with added lines and blob ids. */
+export function changedFiles(repoRoot: string, diffBase: string, head?: string): ChangedFile[] | { error: string } {
+  const range = head ? [diffBase, head] : [diffBase];
+  const names = git(repoRoot, ['diff', '--name-status', '-z', '--no-renames', ...range], 120_000);
+  const diff = git(repoRoot, ['diff', '--unified=0', '--no-color', '--no-renames', ...range], 120_000);
+  if (!names.ok || !diff.ok) return { error: `git diff ${range.join(' ')} failed` };
+  const added = addedLines(diff.out);
+  const parts = names.out.split('\0').filter(Boolean);
+  const out: ChangedFile[] = [];
+  for (let i = 0; i + 1 < parts.length; i += 2) {
+    const status = parts[i]!.slice(0, 1);
+    const file = parts[i + 1]!;
+    let blob = 'deleted';
+    if (status !== 'D') {
+      const r = head ? git(repoRoot, ['rev-parse', `${head}:${file}`]) : git(repoRoot, ['hash-object', '--', file]);
+      blob = r.ok ? r.out.trim() : 'unreadable';
+    }
+    out.push({ file, status, blob, added: added.get(file) ?? [] });
+  }
+  return out;
+}
+
+function isMigration(rule: MigrationRule | null, file: string): boolean {
+  return !!rule && file.startsWith(`${rule.dir}/`) && rule.id.test(path.posix.basename(file));
+}
+
+const STATUS_WORD: Record<string, string> = { A: 'added', M: 'modified', D: 'deleted', T: 'type changed' };
+
+function classHits(cls: ApprovalClass, files: ChangedFile[], migrations: MigrationRule | null): ApprovalHit[] {
+  const hits: ApprovalHit[] = [];
+  const pathRes = (cls.paths ?? []).map(globToRegExp);
+  for (const f of files) {
+    if (f.file === APPROVAL_CLASSES_PATH || matchesAny(cls.allowed_paths ?? [], f.file)) continue;
+    const byMigration = cls.migrations === true && isMigration(migrations, f.file);
+    if (byMigration || pathRes.some(re => re.test(f.file))) {
+      hits.push({ class: cls.name, file: f.file, line: f.added[0]?.line ?? 1, via: byMigration ? 'migration' : 'path', text: STATUS_WORD[f.status] ?? f.status, declared: true, effect: `path\0${f.file}\0${f.blob}` });
+    }
+    for (const pattern of cls.patterns ?? []) for (const l of f.added) {
+      if (l.text.includes(pattern)) hits.push({ class: cls.name, file: f.file, line: l.line, via: 'pattern', text: l.text.trim().slice(0, 160), declared: true, effect: `line\0${f.file}\0${l.text.trim()}` });
+    }
+  }
+  return hits;
+}
+
+/** The scope token binds a citation to these exact effects: any added, removed or edited effect changes the digest. */
+export function scopeOf(name: string, hits: ApprovalHit[]): ApprovalScope {
+  const effects = [...new Set(hits.map(h => h.effect))].sort();
+  const digest = createHash('sha256').update(`${name}\n${effects.join('\n')}`).digest('hex');
+  return { class: name, digest, token: `${name}@${digest.slice(0, 12)}`, effects, files: [...new Set(hits.map(h => h.file))].sort(), hits: hits.map(h => `${h.file}:${h.line}`) };
+}
+
+/** Declared hits, report-only built-in hits, and one scope per declared class with hits. */
+export function scanApprovalClasses(config: ApprovalClassesConfig | null, source: string, files: ChangedFile[], migrations: MigrationRule | null): ApprovalScan {
+  const classes = config?.classes ?? [];
+  const hits = classes.flatMap(cls => classHits(cls, files, migrations));
+  const claimsMigrations = classes.some(c => c.migrations === true);
+  const report_only: ApprovalHit[] = claimsMigrations ? [] : files.filter(f => isMigration(migrations, f.file)).map(f => ({
+    class: 'migrations', file: f.file, line: f.added[0]?.line ?? 1, via: 'migration' as const, text: STATUS_WORD[f.status] ?? f.status, declared: false, effect: `path\0${f.file}\0${f.blob}`,
+  }));
+  const scopes = classes.map(cls => hits.filter(h => h.class === cls.name)).filter(own => own.length).map(own => scopeOf(own[0]!.class, own));
+  return { source, classes: classes.length, hits, report_only, scopes };
+}
+
+export interface ScanRequest { repoRoot: string; base: string; head?: string; diffBase?: string }
+export type ScanOutcome =
+  | { scan: ApprovalScan; absent: boolean }
+  | { errors: ApprovalClassesError[]; source: string }
+  | { unavailable: string; source: string }
+  | { error: string };
+
+/** Load the base's classes and migration rule, diff since the merge base, scan. Skips the diff when nothing could match. */
+export function runApprovalScan(req: ScanRequest): ScanOutcome {
+  const load = loadApprovalClasses(req.repoRoot, req.base);
+  if ('unavailable' in load) return { unavailable: load.unavailable, source: load.source };
+  if ('errors' in load) return { errors: load.errors, source: load.source };
+  const migrations = baseMigrationRule(req.repoRoot, req.base);
+  const absent = 'absent' in load;
+  if (absent && !migrations) return { scan: scanApprovalClasses(null, load.source, [], null), absent };
+  const mergeBase = req.diffBase ? undefined : git(req.repoRoot, ['merge-base', baseRef(req.base), req.head ?? 'HEAD']);
+  const diffBase = req.diffBase ?? (mergeBase?.ok ? mergeBase.out.trim() : undefined);
+  if (!diffBase) return { error: `no merge base between ${baseRef(req.base)} and ${req.head ?? 'HEAD'}; pass --diff-base <sha>` };
+  const files = changedFiles(req.repoRoot, diffBase, req.head);
+  if ('error' in files) return files;
+  return { scan: scanApprovalClasses(load.config, load.source, files, migrations), absent };
+}
+
+export const CITATION_TEMPLATE = 'Approved by <owner> <YYYY-MM-DD> via <plan sha|comment or review URL|ref>';
+
+export function renderApprovalScan(scan: ApprovalScan, absent: boolean): string {
+  const lines = [
+    ...scan.hits.map(h => `APPROVAL_CLASS: ${h.class} ${h.file}:${h.line} (${h.via}) — ${h.text}`),
+    ...scan.report_only.map(h => `APPROVAL_CLASS: ${h.class} ${h.file}:${h.line} (built-in, report-only) — ${h.text}`),
+    ...scan.scopes.map(s => `APPROVAL_SCOPE: ${s.token} effects=${s.effects.length} files=${s.files.join(',')}; cite: ${CITATION_TEMPLATE} for ${s.token}`),
+  ];
+  const summary = absent ? `none (no ${APPROVAL_CLASSES_PATH} on the base)` : scan.hits.length ? `found=${scan.hits.length}` : 'ok';
+  lines.push(`APPROVAL_CLASSES: ${summary} classes=${scan.classes} report_only=${scan.report_only.length} source=${scan.source}`);
+  return lines.join('\n') + '\n';
+}
diff --git a/lib/headless-artifacts.ts b/lib/headless-artifacts.ts
index ae6938d9b..e46d2336d 100644
--- a/lib/headless-artifacts.ts
+++ b/lib/headless-artifacts.ts
@@ -82,6 +82,8 @@ export interface ShipReceipt {
   thread?: string; tree?: string; gate_reuse?: string; policy?: string; queue_mode?: string; preregistration?: string; history?: string;
   // C-pregate (C8): the pre-gate's verdict against this head and its remote obligations (publication requires their receipts).
   pregate?: string; requires_remote?: string[];
+  /** Approval classes (lib/approval-citations.ts): source, status, one record per declared class with hits, report-only built-in hits. */
+  approval?: Record<string, unknown>;
   // C-pregate (C6): issue links the body carries, by intent.
   // Related open PRs by other authors (Lane D): `supersedes` / `credit` only on the owner's confirmation.
   issues?: { fixes: number[]; refs: number[]; flakes: Array<{ issue: number; run: string }>; related?: Array<{ pr: number; repo?: string; author: string; closes: number[]; supersedes?: boolean; credit?: boolean }> };
@@ -199,6 +201,7 @@ export const ARTIFACT_SCHEMAS = {
       session_kind: str, artifacts_consumed: { ...str, description: '<n>/<m>' }, run: str,
       thread: str, tree: { enum: ['same-modulo-stamps', 'changed', 'not-compared'] }, gate_reuse: str, policy: str, queue_mode: str, preregistration: str, history: str,
       pregate: { ...str, description: 'pass|warn|requires-remote cleared … @<tree> from pregate.json, current for this head' }, requires_remote: strList,
+      approval: { type: 'object', description: 'approval classes: { source, status: checked|unavailable, classes: [{ class, scope, effects, citation: verified|unverified, approved_by, date, via, binding, evidence }], report_only }' },
       issues: { type: 'object', properties: { fixes: { type: 'array', items: { type: 'integer' } }, refs: { type: 'array', items: { type: 'integer' } }, flakes: { type: 'array', items: { type: 'object', required: ['issue', 'run'], properties: { issue: { type: 'integer' }, run: str } } }, related: { type: 'array', items: { type: 'object', required: ['pr', 'author', 'closes'], properties: { pr: { type: 'integer' }, repo: str, author: str, closes: { type: 'array', items: { type: 'integer' } }, supersedes: { type: 'boolean' }, credit: { type: 'boolean' } } } } } },
     },
   },
diff --git a/lib/result-codes.ts b/lib/result-codes.ts
index 702e17a2e..370c0b4fc 100644
--- a/lib/result-codes.ts
+++ b/lib/result-codes.ts
@@ -736,6 +736,32 @@ export const RESULT_CODES = {
     summary: 'an added or changed test line compares an elapsed wall-clock or CPU time against a bound, or sleeps and then asserts (a warning, not a block)',
     fix: 'assert on the outcome, an injected clock or a forced deadline instead; when the bound is the contract, add `gstack-timing-ok: <reason>` in a comment on the line or the line above',
   },
+  // Field list 2, W2 (approval classes) and W3 (state-machine round-trip matrix).
+  APPROVAL_CLASSES_INVALID: {
+    anchor: 'approval-classes-invalid',
+    summary: '`.gstack/approval-classes.json` is malformed, a class matches nothing, or a path escapes the repository',
+    fix: 'keep `classes` a non-empty list of uniquely named classes, each with `paths`, `patterns` or `migrations: true`, and every glob repo-relative (`gstack-approval-classes validate` checks the working-tree copy)',
+  },
+  APPROVAL_CLASS_FOUND: {
+    anchor: 'approval-class-found',
+    summary: 'the branch changes something a declared approval class covers',
+    fix: 'get the owner\'s approval and put `Approved by <owner> <YYYY-MM-DD> via <plan sha|comment or review URL> for <class>@<digest12>` in the PR body, using the APPROVAL_SCOPE token the check printed',
+  },
+  APPROVAL_CITATION_MISSING: {
+    anchor: 'approval-citation-missing',
+    summary: 'a declared approval class has no citation that resolves and binds to its current effects, so no receipt was written',
+    fix: 'add an `Approved by` line whose plan (with --approval-run <dir>) or maintainer comment names the APPROVAL_SCOPE token or the class and every effect path; for evidence gstack cannot read, attest it with `for <class>@<digest12>` on the line',
+  },
+  APPROVAL_SOURCE_UNAVAILABLE: {
+    anchor: 'approval-source-unavailable',
+    summary: 'origin/<base> is not a resolvable commit, so the committed .gstack/approval-classes.json cannot be read and nothing was checked',
+    fix: 'git fetch origin <base> (classes are never read from the working tree)',
+  },
+  STATE_MATRIX_INCOMPLETE: {
+    anchor: 'state-matrix-incomplete',
+    summary: 'the state-machines specialist output lacks a kind × owner action cell, maps a cell to a test that does not exist, or leaves an untested cell without a CRITICAL finding',
+    fix: 'rerun the state-machines specialist on the same diff; its review coverage stays incomplete until gstack-state-matrix check passes',
+  },
 } as const satisfies Record<string, ResultCode>;
 
 export type ResultCodeName = keyof typeof RESULT_CODES;
diff --git a/lib/ship-receipt.ts b/lib/ship-receipt.ts
index 3bd17b167..9350b4169 100644
--- a/lib/ship-receipt.ts
+++ b/lib/ship-receipt.ts
@@ -7,13 +7,14 @@
  * thread id against an owner-maintained thread cohort).
  */
 import { ARTIFACT_SCHEMAS, checkSchema, type ShipReceipt, type ValidationError } from './headless-artifacts';
+import { approvalSummary } from './approval-citations';
 import { renderIssueLines } from './issue-links';
 
 export const RECEIPT_FENCE = 'gstack-ship-receipt';
 const KEY_ORDER: Array<keyof ShipReceipt> = [
   'schema_version', 'pr', 'head', 'version', 'base', 'gated_tree', 'predecessor', 'tree', 'gate_reuse', 'gate', 'ci', 'spend_usd',
   'session_kind', 'artifacts_consumed', 'run', 'thread', 'policy', 'queue_mode', 'preregistration', 'history',
-  'pregate', 'requires_remote', 'issues',
+  'pregate', 'requires_remote', 'issues', 'approval',
 ];
 
 /** Keys in the fixed order so identifiers lead; undefined values are dropped. */
@@ -78,6 +79,7 @@ export function receiptSummaryLine(r: ShipReceipt): string {
   if (r.predecessor) parts.push(`predecessor=${r.predecessor.slice(0, 12)}`);
   if (r.session_kind) parts.push(`session_kind=${r.session_kind}`);
   if (r.artifacts_consumed) parts.push(`artifacts_consumed=${r.artifacts_consumed}`);
+  if (r.approval) parts.push(`approval=${approvalSummary(r.approval)}`);
   return `SHIP_RECEIPT: ${parts.join(' ')}`;
 }