is-commit-rules

name	is-commit-rules
description	Commit message formatting rules. Apply whenever creating or amending a git commit.

Commit Message Rules

Apply these rules on top of your usual commit message conventions (imperative mood, meaningful subject, etc.). They add constraints; they don't replace your defaults.

Rule 1 — Explain why, keep it concise

The subject states what changed in imperative mood. The body MUST explain why — the motivation, constraint, or trade-off that the diff alone cannot reveal. Do NOT restate what or how: those are already visible in the modification itself.

Keep the body short. A few lines is usually enough; add length only when the why genuinely needs it (prior incident, hidden constraint, non-obvious decision). A reviewer should grasp the motivation in seconds, not paragraphs.

Rule 2 — 72-column limit

Subject and every body line MUST wrap at 72 columns. Exception: in the body, raw pasted content (logs, errors, stack traces, command output) may exceed 72 when wrapping would hurt readability.

Rule 3 — Do NOT generate a Change-Id trailer

Never add Change-Id: to a new commit; the project's git hook generates it automatically.

Rule 4 — Preserve existing trailers

When amending, keep all existing trailers (Change-Id:, Refs:, Closes:, any Key: value tags at the end) exactly as-is — no modification, reordering, or removal.

Rule 5 — Keep the message up-to-date when amending

After amending, update the subject/body if the scope or intent changed (still respecting Rules 1, 2, 3 and 4). Do not describe the changes between patchsets; describe the final state.

Rule 6 — Always include the Co-Authored-By trailer

Every commit MUST end with the Co-Authored-By: trailer from your system prompt, regardless of repo style. When amending, combine with Rule 4: keep an existing one, or add it if missing.

Rule 7 — Redmine ticket trailers (Refs / Closes)

This project links commits to Redmine tickets via:

• Refs: #XXX #YYY — related to those tickets, work not finished.
• Closes: #XXX #YYY — final commit for those tickets.

Syntax: # + numeric id, multiple ids space-separated on one line.

Applies only to new commits, not amends:

1. If the user named tickets (and Refs vs. Closes), set the trailer(s) without further prompting.
2. Otherwise, ASK before committing whether any tickets should be Refs:'d or Closes:'d, and wait for the answer.

When amending, do not invoke this rule: existing trailers are preserved per Rule 4, and no new ones are added unless the user asks.

Rule 8 — RunTests: for @slow Behave scenarios

When the diff includes Behave .feature files, check whether any added or modified scenarios carry the @slow tag. If so, a RunTests: footer is required so those scenarios run during review (they are otherwise excluded and run only in nightly campaigns).

Reference the scenario's identifying tag(s) in RunTests: (typically @redmine_XXXXX but may be any tag that uniquely identifies the scenario).

• 1–3 impacted tags — list them all: RunTests: @redmine_A @redmine_B
• More than 3 — do not enumerate all tags; list the impacted scenarios, propose a dedicated grouping tag to add to those scenarios in the feature files, and ask the developer whether they want to add that tag to the commit.