v1.72.0.0 feat: Aside recommended driver for third-party web actions (#2710)

* fix(browse): never chmod shared, symlinked, or foreign-owned dirs to 0700

restrictDirectoryPermissions unconditionally chmodded its target. On hosts
where the process holds CAP_FOWNER (Docker as root, CI sandboxes) that
chmod SUCCEEDS on root-owned /tmp whenever a state file is configured
there (BROWSE_STATE_FILE=/tmp/x.json derives stateDir=/tmp), and a 0700
/tmp breaks access(2)-based checks machine-wide for every other process.

The POSIX branch now refuses shared sticky dirs, world-writable mounts
under root, foreign-owned dirs, and symlinked state dirs; refusals warn
once per process instead of failing silent; owned-but-unreadable dirs
keep their chmod self-repair; and the check-then-act race is closed with
fd-anchored O_NOFOLLOW + fstat/fchmod on a single inode.

Regression tests cover the sticky-dir, foreign-uid, mkdirSecure-reapply,
and symlinked-dir shapes.

* fix: hash with sha256sum before shasum on Linux (config slugs + setup verify)

shasum is perl/macOS; coreutils-only Linux ships sha256sum. Two call
sites hard-coded shasum: gstack-config's sha8_of/sha16 (so
resolve-user-slug exited 127 for any Linux user with a git email, the
Layer-3 fallback) and the generated bun-installer checksum snippet in
the browse/qa NEEDS_SETUP flow (spurious "checksum mismatch" on the
same distros). Both now resolve sha256sum first and fall back to
shasum -a 256.

New shim-PATH tests pin BOTH hasher branches of sha8_of to a known
vector and cover the sha8->sha16 collision escalation end to end.

* feat(contract): Aside is the recommended driver for third-party web actions

The Third-Party Web Actions contract (ship, spec, office-hours,
land-and-deploy, setup-deploy) now names the Aside AI browser as the
recommended driver: it acts across the user's real logged-in sessions,
which is what vendor-dashboard moments need. Supersedes the v1.65.0.0
de-Aside stance by explicit user directive (2026-08-27).

Detection is a runtime probe (command -v + aside --version under a
portable gtimeout/timeout/bare guard; nonzero exit = not detected).
Consent options render per detection state with Aside recommended and
the first-party stack ($B headed + handoff, GStack Browser) as the
universal fallback. Absent on macOS, the contract mentions the
aside.com download (macOS 15+) once per task; gstack never runs an
installer and binary presence is never consent. Drive discipline:
step-wise over whole-task delegation, vendor confirm mode on, vendor
skill/--help text scoped to operational syntax only, secrets minimized
(autofill / human-used copy buttons), Apple credential creation never a
drive target in any skill, failure path quotes redacted errors and
falls back only with fresh consent.

test/third-party-actions.test.ts pins every load-bearing sentence (21
tests) plus repo-wide tripwires: an aside command allowlist
(--version/--help only, code spans AND prose) and a ban on Aside
installer invocations across all generated docs. Budget ratchet
fixture and carve skeleton ceilings refreshed in this commit per the
ratchet protocol.

* chore: regenerate remaining browse-setup snippet consumers

The sha256sum-first checksum fallback in the generated NEEDS_SETUP
snippet renders into every browse-consuming skill, not just browse/qa.
Mechanical regen of the other ten consumers; no template changes here.

* test: consent-gate E2E suite + functional fs-capability probes

Five hermetic gate-tier E2E cases (tpa-present / absent-linux / broken /
absent-darwin / apple-ban) drive the real contract section through
claude -p with PATH shims for aside and uname; the absent cases filter
any REAL aside binary out of the child PATH and assert absence with
Bun.which before spawning, so dev machines cannot leak into detection.
Registered per-case in E2E_TOUCHFILES/E2E_TIERS with template-level
deps (ship/SKILL.md.tmpl, gen-skill-docs.ts) and added to the evals.yml
matrix with tier: gate. eval:bg:periodic's detach timeout rises to
36000s for the grown periodic shard census (floor-enforced by
test/eval-detach-timeout-floor.test.ts); CLAUDE.md doc updated to match.

test/helpers/fs-caps.ts adds canRevokeWrites/canRevokeReads functional
probes; 13 chmod-based tests swap their uid-0-only guards for the
probes so suites skip honestly on CAP_DAC_OVERRIDE containers (this
sandbox: uid 1000 with full caps) instead of asserting revocations the
kernel ignores. path-validation's symlink test targets /etc/passwd
(exists everywhere; /etc/crontab is absent on Amazon Linux).

* docs: file the Aside follow-ups in TODOS

Phase-2 QA logged-in-evidence path (P3), a hostile-vendor-skill E2E for
the contract's override sentence (P2), and fd-anchoring the file-level
permission writes to match the directory hardening (P3).

* chore: bump version and changelog (v1.72.0.0)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* docs: update project documentation for v1.72.0.0

docs/skills.md: Third-Party Web Actions subsection under /ship (Aside
recommended driver, consent rules, credential boundaries). BROWSER.md:
"Aside and third-party drives" subsection under Real-browser mode + ToC
entry, including the no-gstack-side-audit-trail caveat (ship adversarial
finding 12). TODOS.md: mark the finding-12 doc note done.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* docs: apply cross-model doc review fixes for v1.72.0.0

docs/skills.md: restore the /ship closing line above the new subsection.
BROWSER.md: ToC label matches the heading; BROWSE_STATE_FILE env row
documents the new dir-hardening refusal + one-time warning. CHANGELOG:
correct the hasher precedence wording (sha256sum first, shasum fallback)
and the fs-caps count (14 test files, verified against the diff).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* docs: close cross-model doc-review gaps for v1.72.0.0

setup's manual bun-verify instruction gets the same sha256sum-first
fallback the automated snippet got (coreutils-only Linux); BROWSER.md's
BROWSE_STATE_FILE row now lists the under-root world-writable refusal;
test-cost ceilings in CLAUDE.md/CONTRIBUTING.md updated for the five
new gate E2E cases (~$4.20 E2E / ~$4.35 evals).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(test): gate the symlink-refusal test to POSIX and drop the umask assumption

The symlink regression test exercised the POSIX O_NOFOLLOW branch but ran
on Windows, where restrictDirectoryPermissions takes the icacls branch and
stat has no POSIX modes (0o666 always) — windows-free-tests failed on
mode 493 vs 438. Early-return on win32 like every sibling test in the
file, and assert the target's mode is UNCHANGED (captured post-mkdir)
instead of hardcoding 0o755, which a strict umask would also break.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

test/user-slug-fallback.test.ts

@@ -15,7 +15,8 @@
  */
 
 import { describe, test, expect, beforeEach, afterEach } from 'bun:test';
-import { mkdtempSync, existsSync, readFileSync, writeFileSync, rmSync, mkdirSync } from 'fs';
+import { mkdtempSync, existsSync, readFileSync, writeFileSync, rmSync, mkdirSync, symlinkSync } from 'fs';
+import { createHash } from 'crypto';
 import { join } from 'path';
 import { tmpdir } from 'os';
 import { spawnSync } from 'child_process';
@@ -112,6 +113,114 @@ describe('resolve-user-slug fallback chain', () => {
   });
 });
 
+describe('sha8_of portable hash (sha256sum → shasum fallback)', () => {
+  // sha8_of must work on coreutils-only Linux (no shasum: the exit-127
+  // regression) AND on stock macOS (no sha256sum). The ambient PATH decides
+  // which branch runs, so a plain subprocess call only ever covers one branch
+  // per platform. Pin BOTH deterministically: extract the real function text
+  // from bin/gstack-config (no drift-prone copy) and run it under /bin/sh
+  // with a shim-only PATH that makes exactly one hasher visible. The wrong
+  // branch exits 127 (its tool is absent from the shim dir), so branch
+  // selection is asserted structurally, not inferred.
+  const EXPECTED = '2cf24dba'; // sha256("hello") = 2cf24dba5fb0a30e2…
+
+  function sha8FnSource(): string {
+    const src = readFileSync(CONFIG_BIN, 'utf-8');
+    const m = src.match(/^sha8_of\(\) \{\n[\s\S]*?\n\}/m);
+    if (!m) throw new Error('sha8_of() not found in bin/gstack-config');
+    return m[0];
+  }
+
+  /** Absolute-path sha256 pipeline for shims (host has sha256sum OR shasum). */
+  function realHasherLine(): string {
+    const sha256sum = Bun.which('sha256sum');
+    if (sha256sum) return `exec ${sha256sum} "$@"`;
+    const shasum = Bun.which('shasum');
+    if (shasum) return `exec ${shasum} -a 256 "$@"`;
+    throw new Error('neither sha256sum nor shasum available on this host');
+  }
+
+  function runSha8(shimDir: string) {
+    const result = spawnSync('/bin/sh', ['-c', `${sha8FnSource()}\nsha8_of "hello"`], {
+      encoding: 'utf-8',
+      env: { PATH: shimDir }, // ONLY the shim dir: absent tools are really absent
+      timeout: 5000,
+    });
+    return { stdout: (result.stdout || '').trim(), status: result.status ?? -1, stderr: result.stderr || '' };
+  }
+
+  function makeShimDir(): string {
+    const dir = mkdtempSync(join(tmpdir(), 'gstack-sha8-shim-'));
+    const cut = Bun.which('cut');
+    if (!cut) throw new Error('cut not on PATH');
+    symlinkSync(cut, join(dir, 'cut'));
+    return dir;
+  }
+
+  test('coreutils-only PATH (sha256sum present, shasum absent) — the Linux exit-127 regression', () => {
+    const shim = makeShimDir();
+    try {
+      writeFileSync(join(shim, 'sha256sum'), `#!/bin/sh\n${realHasherLine()}\n`, { mode: 0o755 });
+      const result = runSha8(shim);
+      expect(result.stderr).toBe('');
+      expect(result.status).toBe(0);
+      expect(result.stdout).toBe(EXPECTED);
+    } finally {
+      rmSync(shim, { recursive: true, force: true });
+    }
+  });
+
+  test('sha256sum absent falls back to `shasum -a 256` with identical output (macOS branch)', () => {
+    const shim = makeShimDir();
+    try {
+      // Arg-validating shasum shim: wrong/missing `-a 256` exits 64, which
+      // would surface as a failed pipeline — pins the exact invocation.
+      writeFileSync(
+        join(shim, 'shasum'),
+        `#!/bin/sh\n[ "$1" = "-a" ] && [ "$2" = "256" ] || exit 64\nshift 2\n${realHasherLine()}\n`,
+        { mode: 0o755 },
+      );
+      const result = runSha8(shim);
+      expect(result.stderr).toBe('');
+      expect(result.status).toBe(0);
+      expect(result.stdout).toBe(EXPECTED); // same vector ⇒ branches are equivalent
+    } finally {
+      rmSync(shim, { recursive: true, force: true });
+    }
+  });
+});
+
+describe('endpoint-hash collision escalation (sha8 → sha16)', () => {
+  // endpoint_hash_with_collision_check's sha16 arm carries its own portable
+  // hash pipeline (sha256sum → shasum). This drives it end-to-end through the
+  // real binary: a gbrain MCP URL in $HOME/.claude.json plus config keys at
+  // BOTH the sha8 and sha16 namespaces is the recorded-collision evidence
+  // that makes `endpoint-hash` emit the 16-char hash. Skipped where jq is
+  // absent (the script itself degrades to 'local' there).
+  test('emits sha8 normally, sha16 when a stored sha16-namespaced key exists', () => {
+    if (!Bun.which('jq')) return; // endpoint_hash requires jq; degrades to 'local' without it
+    const url = 'https://gbrain.example.test/mcp';
+    const hex = createHash('sha256').update(url).digest('hex');
+    const sha8 = hex.slice(0, 8);
+    const sha16 = hex.slice(0, 16);
+    writeFileSync(join(TMP_HOME, '.claude.json'), JSON.stringify({ mcpServers: { gbrain: { url } } }));
+
+    // No collision evidence yet → plain sha8.
+    const plain = runConfig(['endpoint-hash'], { GSTACK_HOME: TMP_HOME });
+    expect(plain.status).toBe(0);
+    expect(plain.stdout.trim()).toBe(sha8);
+
+    // Keys stored at both namespaces → escalate to sha16.
+    writeFileSync(
+      join(TMP_HOME, 'config.yaml'),
+      `brain_trust_policy@${sha8}: personal\nbrain_trust_policy@${sha16}: shared\n`,
+    );
+    const escalated = runConfig(['endpoint-hash'], { GSTACK_HOME: TMP_HOME });
+    expect(escalated.status).toBe(0);
+    expect(escalated.stdout.trim()).toBe(sha16);
+  });
+});
+
 describe('brain_trust_policy@<endpoint-id> namespace', () => {
   test('default value is "unset"', () => {
     const result = runConfig(['get', 'brain_trust_policy@deadbeef'], { GSTACK_HOME: TMP_HOME });