[anth-volk]

Fixes #51

What this does

Fails a pull request whose base, or whose stack's final target, is main when its description does not start with Fixes #N naming an open issue here, and registers that as a rule. 16.1 · 6 in the plan; stacked on #50. Making the check required on main is 16.1 · 7, a manual ruleset change.

• The workflow. The new .github/workflows/pr-description.yaml runs on pull_request events opened, edited, reopened and synchronize, for pull requests whose base is main (branches: [main]). In a stack that gh stack links on GitHub, GitHub gives every pull request the stack's final target, main, as its base, so the check runs on each pull request of this stack too, as CI does (it ran on this one, whose displayed base is Check that workflow steps are single commands, and that tools scripts pass shellcheck and have tests #50's branch). It is a workflow of its own, so editing a description reruns only this check. Its one job, pr-description, is named "PR description", the name the ruleset will require, and skips closed pull requests (GitHub also sends edited for them, and merging closed their issue). Permissions: contents, issues and pull-requests read.
• The check. python -m scripts.rules.pr_description (new, in the rules tool, standard library only) reads the description from the event payload. Its first line must be exactly Fixes #N, read as the simulation API's check reads it: CRLF, CR or LF end a line, trailing spaces and tabs are ignored, leading whitespace fails, a missing or empty description fails, and N has no leading zero. It then looks N up with scripts.rules.issues.require_open_issue, the lookup Add the rules registry tool, reading repository-specific values from the registry, and run it on pull requests #40 moved into the tool for this, which refuses a pull request number, a closed issue, a missing one and one moved to another repository. A failure is one ::error annotation that says what is wrong and how to fix it, naming the rule.
• The rule. emitter.process.pr-tracking-issue, enforced by the workflow job's step "Check the first line and the tracking issue". Its proof uses two real descriptions: Release automatically on every merge to main #13's, which named no issue, fails, and Keep telemetry running after an unreadable saved login or a malformed collector answer, and refuse an unsendable collector token #38's, Fixes #37, passes. [discovery].workflows now includes pr-description.yaml. The relock pull requests from Pin one uv version, install and test from uv.lock, and relock weekly with Dependabot #48 already start with Fixes #N.
• Dependabot. A pull request whose author is dependabot[bot] passes without a lookup: Dependabot, which Pin one uv version, install and test from uv.lock, and relock weekly with Dependabot #48 now uses to relock uv.lock, writes its own descriptions and cannot name an issue. Every other author is checked as before (0e19393 red: the new test fails; 15da936 green: the file's 23 tests pass).
• Also: the check's uv run --no-project is a registered exception, as the rules job's are; emitter.ci.pull-request-workflow-structure covers the new workflow; emitter.ci.required-checks no longer calls "Required checks" the only required check, which 16.1 · 7 will make untrue; the README's publication section states the rule.

Test-first record

Commit	Result
9ab7b44 Tests	Red: python -m unittest scripts.rules.tests.test_pr_description fails to import scripts.rules.pr_description; pytest tests/test_workflows.py::test_pull_request_descriptions_are_checked_for_pull_requests_into_main fails, as pr-description.yaml is missing
b2a6bc6 The check, the workflow and the rule	Green: the module's 21 tests pass, including one that runs it as python -m scripts.rules.pr_description through a fake gh, and the workflow test passes. All five guards and guard --base-ref origin/main pass; actionlint 1.7.12 passes
771603b Changelog fragment	bash tools/check-changelog.sh passes

Only the new and changed tests were run, by name; no command ran a test directory or suite.

Review round 1: 8073edc corrected when the check runs (the workflow comment, emitter.process.pr-tracking-issue, emitter.ci.pull-request-workflow-structure, the README) and documented the placeholder description; documentation only, and render, guard and the workflow test pass.

CI

The new workflow is the only workflow change. No existing trigger changes.

Name	Read by	Provider	Wiring
GH_TOKEN	gh api repos/<repository>/issues/<N>, run by scripts/rules/issues.py	GitHub Actions' token for the job (github.token), limited by the workflow's permissions to contents, issues and pull-requests read	The check step's env:
GITHUB_EVENT_PATH	scripts/rules/pr_description.py, for the description	Set by the runner on pull_request events	Present in every step
GITHUB_REPOSITORY	scripts/rules/pr_description.py, for the issue's repository	Set by the runner	Present in every step

No secret or variable is involved. The workflow has run on this pull request (see above); its first run failed on the placeholder description gh stack submit --auto gives a new pull request, and passed once the description was replaced, which the README now says. Unverified: a run on a pull request from a fork, which gets a read-only token; that is enough for the check.

Release

The fragment is changelog.d/pr-description-check.changed.md, a patch bump: merging releases the next patch version of both distributions. The wheels are unchanged, and the source archive leaves the new module out with the rest of scripts/rules/.

🤖 Generated with Claude Code