stack/agents/darkwing/work/slice1-s1/build-r2.md

Row 36, S1, round 2

Darkwing, 2026-10-04. Answers Filbert's round 1 review (#1518 comment 26724, record agents/filbert/work/slice1-s1-review/review-r1.md). Base is still fef4b362. Nothing in the candidate is committed, staged or pushed.

build-r2.patch (sha256 a27890d5c70c5dd38d6b98ce4badfff6334c1cc0c485dcee7c90b1e6438e8a15) replaces round 1's build.patch. It covers the same 34 files. build-r2-manifest.sha256 (sha256 869168c702c272b051bc957a4a4314df962553ac432a5c2c5210f5ba1291afc7) pins them. Six files changed from round 1, and r1-to-r2.diff shows only those. In a fresh clone at fef4b362 the patch applies, the manifest checks 34/34, and the business tests pass 60/60. Round 1's build.md still describes everything else.

B1, launch and role.launch

• checkLaunch refuses a launch.by whose definition doesn't hold role.launch within-role. launch.by: "cto" now refuses with "launch.by names cto, whose role cto doesn't hold role.launch within-role".
• resolveInstance sets launch only when the instance is launch.by and role.launch is still within-role after limits.authority. Otherwise launch is null and role.launch is removed from both lists. launch is set exactly when classify(record, "role.launch") is within. The README says so, and still tells a launcher to ask classify (your n4).
• Tests:
  • the cto refusal, in business.test.mjs;
  • limits.authority without role.launch for pm, at the agent layer and at the project layer: launch is null and the verb is gated;
  • a second pm-definition instance, pm2, as the launcher: pm is gated with launch null, and pm2 is within with launch set. This replaces round 1's launch.by: "cto" case, which now refuses at validation.

B2, cross-role narrowing

New test: coder with limits.authority of task.update.assigned, git.push.working and task.scope.change. task.reassign (cross-role in the definition, left out of the allowlist) classifies as gated, task.scope.change stays cross, and review.request is gated. Your M3 is now caught (R3 below).

n1, the business file check

I fixed this too, since it was in a file I was already changing. readJsonFile now opens the file once with O_NOFOLLOW | O_NONBLOCK, runs fstat on that descriptor, and reads from the same descriptor. The lstat is gone, so there's no second lookup to race. A caller can pass a checkStat callback, which sees the descriptor's stat before the read. loadBusiness uses it for the owner and mode checks. Role and project files use the same reader without a callback. The error messages and exit codes are unchanged:

• missing: "not found", 4;
• a symbolic link (ELOOP) or anything that isn't a regular file: "must be a regular, non-symbolic-link file", 4.

O_NONBLOCK keeps a FIFO from blocking the open. Tests:

• A group-writable file with invalid JSON refuses for its mode (660), not for its JSON. That shows the check runs before the read.
• A directory and a FIFO under the business name both refuse with exit 4. The FIFO case runs in a child process with a 5 s timeout, because an openSync that blocks would hang the test process past node:test's own timeout.

n2: left as is, as you suggested.

Tests and suites

Node 26.8.1 on the host, output teed (suites-r2.txt):

• node --test packages/business/tests/: 60/60, up from 57. The new tests are in resolve.test.mjs (2) and business.test.mjs (1), and three existing tests gained cases.
• scripts/test-config.sh 24/24, test-task.sh 98/98, test-conductor.sh 17/17, test-queue.sh 27/27.

Node 24.21.0 in node:24, no network, the clone mounted read-only: node --test "packages/business/tests/*.test.mjs" 60/60.

Mutants (mutants-r2.sh, results in mutants-r2.txt), each against the business tests, all caught:

Mutant	Failures
R1 launch.by role check off	1
R2 launch ignores limits.authority	1
R3 your M3: crossRole not narrowed	1
R4 owner and mode check skipped	1
R5 owner and mode check after the parse	1
R6 O_NOFOLLOW dropped	2
R7 a non-regular file accepted	1
R8 O_NONBLOCK dropped	1

For S2

Two API changes reach Rocko's S2, both narrowing:

• A business file whose launch.by lacks role.launch now refuses.
• launch can be null for the by instance when limits.authority drops the verb. No function names, argument shapes or record keys changed.