[Hafeok]

Completes: none

What this changes, and why

#169, all three layers from the maintainer's comment of 2026-11-11, implementing ADR 0241. It is stacked on 3da8929c, the approved head of #259–#261, where ADR 0241 is accepted, so it lands after them. Its own commits are the last five. #169 stays open for its last box, the port to the analyzer repository (#65), so this PR completes no issue.

1. One pattern, held once: eng/model-names.cs and eng/model-families.txt.
   • A name is a family word (Opus, Sonnet, Haiku, Fable, Mythos), optionally after Claude, followed by a version.
   • It is matched regardless of case, and only standing alone. So the hyphenated API identifier, the bare Claude, a family word without a version, and a version without a family word all pass.
2. The tool's default: .claude/settings.json. It sets attribution.commit to Co-Authored-By: Claude <noreply@anthropic.com> and attribution.pr to the link line. That is the shape the current settings reference documents; it replaces the deprecated includeCoAuthoredBy.
3. The commit: eng/hooks/commit-msg.
   • It runs eng/model-names.cs --message first, for every author and tool.
   • A Co-Authored-By: trailer naming a model becomes the allowed one, and a repeat folds.
   • A name anywhere else refuses the commit, with the line quoted.
   • Without an SDK it warns and leaves the message to the gate.
4. The gate: model-names in eng/ci.cs.
   • It checks every commit a pull request or a land/ push adds over main, merges included. The range is worked out as eng/issue-refs.cs works it out.
   • Commits reachable from 2cad18d5, the lower bound in the delegate's comment, are left out.
   • Each finding names the commit and the line.
   • model-names-fixtures proves the failure path on every build, and ci.yml's release call skips the range gate, as it skips the others.
5. Documents:
   • AGENTS.md's Every commit says where the rule is held, and names no tool's settings file (ADR 0033);
   • docs/rules/ gains a commit-gate section and model-names.md;
   • a traceability record.

What was measured

• dotnet run eng/model-names.cs -- --fixtures tests/fixtures/model-names: 13 cases, 0 judged wrong. The versions are fictional, so no real model's identifier is in the repository.
• Scratch commits through the real hook, not pushed:

  model-names: a co-author trailer named a model; it now reads `Co-Authored-By: Claude <noreply@anthropic.com>` (ADR 0241).
  commit exit 0
  model-names: the message names a model: "Written with Sonnet 9.9."
  refused commit exit 1
  

• The gate on a commit made with --no-verify:

  FAIL: 1 line(s) name a model (ADR 0241: a commit message never names a model; its identifier is allowed):
    b59e4ebe: "Co-Authored-By: Claude Haiku 9.9 <noreply@anthropic.com>"
  gate exit 1
  

• The lower bound: --range 2cad18d5~4..3da8929c reads 16 commits, none naming a model, which agrees with the delegate's count on Commit gate: a commit message that names a model fails (names refused, ids allowed) #169.
• eng/ci.cs with only licence-headers, decision-sets, issue-refs, dco, model-names, model-names-fixtures, changelog, release, status and land: all pass.

What was found

• A cloud session honours the project-level setting in a single-repository session. A fresh cloud session started from this branch was told to end commits with Co-Authored-By: Claude <noreply@anthropic.com> plus the session link, and wrote exactly that, with the hook switched off. The session that built this PR started without the file, and was told a trailer naming the model. The documentation says nothing about attribution in a project's cloud threads. A managed, command-line or local setting also wins over the shared file, and so does any other tool's default. That is where the hook and the gate take over. The details are on Commit gate: a commit message that names a model fails (names refused, ids allowed) #169.

What is left

• Commit gate: a commit message that names a model fails (names refused, ids allowed) #169's last box: the port to the analyzer repository (Port the ledger gates to the analyzer repository (ADR 0086) #65).
• Issues this touches: Commit gate: a commit message that names a model fails (names refused, ids allowed) #169, in part. A comment on Commit gate: a commit message that names a model fails (names refused, ids allowed) #169 will say what landed and what is left.

---

Checklist

• Issue referenced: Refs #169 on every commit.
• ADR cited: implements ADR 0241.
• Specification updated, or n/a: n/a; docs/rules/model-names.md.
• API baseline updated, or n/a: n/a.
• Conformance baseline updated, or n/a: n/a.
• Tests: fixtures on every eng/ci.cs run, and the hook exercised on scratch commits.
• A new gate's failure path was proven by running it: quoted above.
• Signed off: by the hook, which also ran the new check on each of these commits.
• A traceability record exists: docs/traceability/2026-11-11-issue-169-model-names-in-three-layers.md.
• dotnet run eng/ci.cs passes locally: the process gates and fixtures were run; the full test pipeline is left to CI.

🤖 Generated with Claude Code

https://claude.ai/code/session_01NbWSYQ7rmZCcSgsvBFhZMm

[Hafeok]

Head for approval: 402a4e06b15ba2e74aaf2ed1c64c21616d879387. All 72 other checks are green or skipped, including the publish dry run. The one not green is agent review, which waits on the approval. #259–#261 are on main now, so this pull request sits directly on main with its own five commits. It completes no issue, because #169 stays open for the port to the analyzer repository (#65).

---

Generated by Claude Code