// Proofreads and suggests structural improvements for Git commit messages to ensure style guide compliance, completeness, and accuracy.
| name | gerrit-commit-message-review |
| description | Proofreads and suggests structural improvements for Git commit messages to ensure style guide compliance, completeness, and accuracy. |
Welcome to the definitive engineering reference for formatting, structuring, and preserving metadata inside Git commit messages. This document encapsulates the core conventions for commit hygiene, which are essential to ensuring commit log histories remain clean, readable, and highly traceable across development lifecycles.
Adhering to these standards ensures metadata traceability, and provides clear, long-term context to future developers.
| Chapter Theme / Title | Scope & Objective |
|---|---|
| Commit Title Conventions | Defines stylistic and length requirements for the first line of the commit message to optimize history navigation. |
| Commit Body Structure & Formatting | Outlines instructions to clearly explain the "what" and "why" of the patchset with pragmatic conciseness and precise wrapping. |
| Metadata Footers & Preservations | Enforces the strict preservation of system-critical integration footers (such as Change-Id and issue tracking IDs). |
Context: The title line of a Git commit message is the first line of visual feedback for engineers navigating repository logs. To ensure standard sizing, clarity, and readability, title structures are subject to rigid constraints.
| Rule ID | Principle / Constraint | Priority | Primary Symptom / Trap |
|---|---|---|---|
| T1-01 | Concise & Imperative Commit Titles | High | Writing titles exceeding 60 characters, or utilizing past-tense/progressive verbs (e.g. "Fixed...", "Fixing..."). |
Rule: Commit titles must be 60 characters or less, start with an imperative verb (e.g., "Add", "Fix", "Update", "Remove"), and use sentence case without trailing punctuation.
What: The commit title line must be a concise, imperative sentence summary strictly 60 characters or less.
Applies To: Git commit message first line.
Why: The codebase's core validation rules programmatically block and flag commits with subjects exceeding 60 characters. Keeping the title under this strict limit avoids repository presubmit upload blockages and ensures neat display in CLI tools.
Trap 1: Writing passive, overly long, or descriptive titles using progressive or past tense.
Don't:
Fixing the loading spinner bug in gr-reply-dialog.ts and adding tests
Do:
Fix loading spinner and add test coverage
Context: The body of a commit is a vital repository asset storing the architectural intent behind a change. It must explain engineering decisions with pragmatic conciseness, provide targeted context, and be wrapped strictly for terminal compatibility.
| Rule ID | Principle / Constraint | Priority | Primary Symptom / Trap |
|---|---|---|---|
| T2-01 | Explaining the Context: What and Why | High | Omitting commit bodies entirely, repeating the title, describing "how" instead of "why", or leaving critical design/bug links without context. |
| T2-02 | Strict Line Wrapping at 72 Characters | High | Writing continuous, single-line paragraphs that span past 72 characters, causing awkward wrapping in console windows. |
| T2-03 | Pragmatic Tone, Conciseness, and Anti-Filler | High | Writing verbose, flowery prose, introducing generic engineering philosophy/boilerplate, or using redundant Q&A layouts on simple changes. |
Rule: The commit message body must clearly explain what changes were made and why they were necessary, focusing on context and architectural intent, while maintaining a concise, non-redundant, and pragmatic tone. The body must jump directly into the technical context or problem and must never repeat, rephrase, or start with a high-level introductory summary of the title. For complex, security-sensitive, or high-risk changes, the explanation should explicitly ground the "why" by referencing the relevant issue, bug tracking ID, or design/RFC document.
What: Explanations in the body must detail the problem and the rationale for the solution, leaving the mechanical "how" to be read from the code diff, and omitting generic value propositions of development practices, non-technical fluff, or introductory meta-sentences. The opening paragraph of the body must begin directly with the context or problem being solved and not restate or paraphrase the commit title. If the commit relates to a complex problem or implements an approved design specification, the body should draw from and cite these linked resources to clarify the reasoning in a direct, straightforward manner.
Applies To: Commit message lines following the spacer blank line (line 3 and onward).
Why: Obvious code listings are redundant. Context is key: for complex or sensitive engineering changes, subsequent maintainers must understand the origin of a requirement or design constraint (e.g., a specific bug, CVE, or design specification) without having to guess, establishing clear auditability.
Trap 1: Repeating or rephrasing the title, starting the body with a high-level introductory summary sentence, or omitting concrete context.
The commit title is already the high-level summary of the change. Starting the body of the commit message with a rephrasing, restatement, or introductory "thesis statement" (e.g. "Add the agent and define its corresponding guidelines") is highly redundant and wastes reader time. Do not write introductory meta-sentences; begin the body paragraphs by jumping directly into the technical context or the problem being solved.
Don't:
Fix loading spinner and add test coverage
This change fixes the loading spinner and adds test coverage to gr-reply-dialog.ts.
(Problem: Repeats the title almost verbatim in the body opening.)
Do:
Fix loading spinner and add test coverage
The loading spinner in gr-reply-dialog was experiencing visual jitter
on rapid page transitions due to a race condition in the reactive
lifecycle hook.
This change moves property assignments out of firstUpdated to avoid
unnecessary second-pass rendering, stabilizing the visual state.
(Rationale: Jumps immediately into the concrete problem.)
Trap 2: Omitting context from linked bugs or design documents in complex, critical, or security-sensitive changes.
While simple or minor bug fixes do not need to explicitly reference their issue IDs inside the body, major, high-risk, or architectural modifications that reference external specs, RFCs, or bug tracker tickets should integrate that context into the "why" explanation. Failing to do so makes the commit message look disconnected from its metadata, making review and auditability difficult.
Don't:
Enhance project deletion permission validation
Only users with administrative privileges are allowed to delete a
project, but the server was previously checking for owner status only.
This change corrects the check to require system administrator scope.
Bug: gerrit:40012901
(Problem: A security-sensitive permission model change is being made under a bug, but the body only explains the mechanical change. It completely misses the security context—like the permission bypass mentioned in the bug report—making the reasoning for this risk-heavy change unclear without looking up the bug.)
Do:
Enhance project deletion permission validation
To resolve the permission bypass reported in gerrit:40012901, where
project owners could bypass global security policies to delete resource
containers, we must restrict deletion calls to administrators.
As defined in the project deletion security spec (https://example.com/gerrit-delete-spec),
only system-level administrators should have the capability to
destroy project repositories in production environments.
Bug: gerrit:40012901
(Rationale: Since this is a high-risk change (a security bypass), the body explicitly connects to the bug report gerrit:40012901 and links the authoritative security spec (e.g., https://example.com/gerrit-delete-spec). This establishes bulletproof reasoning and traceability for a critical modification.)
Rule: Wrap the body of all commit messages strictly at 72 characters per line, except for unwrappable URLs, file paths, or commands.
What: Lines in the commit body must have explicit carriage returns at or before 72 columns.
Applies To: Git commit message bodies.
Why: Terminal output screens wrap at standard columns. Explicitly wrapping to 72 characters ensures clean reading in simple text editors, CLI viewers, and patch viewers.
Trap 1: Appending full paragraphs without manual word wrapping.
Don't:
This change refactors the core caching helper and resolves a race condition that occurs when the same component gets disconnected rapidly from the DOM during teardown, which historically resulted in an uncaught exception.
Do:
This change refactors the core caching helper and resolves a race
condition that occurs when the same component gets disconnected
rapidly from the DOM during teardown, which historically resulted
in an uncaught exception.
Rule: Commit messages must be concise, direct, and free of conversational filler, obvious generalities, marketing/PR speak, or excessive boilerplate structure. Every sentence must serve to communicate technical context.
What: Avoid long-winded introductions (e.g. "To ensure standard high-quality..."), platitudes (e.g. "Commit messages are vital repositories of engineering intent..."), and rigid Q&A-style templates (like "What is changing / Why this is necessary" headers) unless the change is highly complex and structurally demands them. Keep explanations simple, direct, and focused on the technical problem and its solution.
Applies To: Git commit message bodies.
Why: Verbose, flowery, or highly templated commit messages clutter repository logs and increase cognitive load for engineers searching history. A staff engineer's time is valuable; the commit message must deliver maximum signal-to-noise ratio.
Trap 1: Including generic software engineering justifications or explaining why code review, testing, or good practices are important in general. Do not write essays on general design philosophy in the commit message. Stick strictly to the specific change's technical facts.
Don't:
Register gerrit-commit-message-review agent and skill
To enforce rigorous commit log hygiene across this repository, this
change registers the new 'gerrit-commit-message-review' AI reviewer
agent and establishes its associated quality guidelines.
Commit messages are permanent repositories of engineering intent, but
manual review is prone to human oversight. Under the feature request
in Issue 505405738, this system automates audit checks to provide
instant, high-fidelity feedback. By deploying a specialized agent that
evaluates formatting style, structural completeness, and footer
integrity, developers receive automated proofreading findings directly
in the Gerrit Checks UI (with ready-to-apply autofixes where
applicable).
(Problem: Highly verbose, generic text explaining general AI reviewer value propositions and repository hygiene, filled with fluff sentences like "Commit messages are permanent repositories...")
Do:
Register gerrit-commit-message-review agent and skill
To address Issue 505405738 and automate commit log hygiene audits,
this change registers the new agent to trigger automatically on
COMMIT_MSG changes. The accompanying skill definition outlines rules
for subject-line format, strict 72-character line wrapping, context and
intent explanation, and strict preservation of integration footers.
Bug: Issue 505405738
(Rationale: High signal-to-noise ratio. Eliminates redundant introductory restatements and begins directly with the problem and technical mechanism.)
Trap 2: Forcing complex multi-section layouts (like bullet points or Q&A headers) for straightforward, medium-sized, or simple changes. Use simple, direct paragraphs instead of lists and structural headings whenever possible. Only use numbered lists when listing a sequence of highly distinct architectural changes.
Don't:
Fix loading spinner and add test coverage
What is changing:
1. The loading spinner in gr-reply-dialog.ts is fixed.
2. Property assignments are moved out of firstUpdated to avoid dual rendering.
3. Tests are added.
Why this is necessary:
The loading spinner was experiencing visual jitter on rapid page transitions
due to a race condition in the reactive lifecycle hook, which is bad for UX.
(Problem: Trivial bug fix is forced into a multi-headed structure with redundant wording.)
Do:
Fix loading spinner and add test coverage
The loading spinner in gr-reply-dialog was experiencing visual jitter
on rapid page transitions due to a race condition in the reactive
lifecycle hook.
This change moves property assignments out of firstUpdated to avoid
unnecessary second-pass rendering, stabilizing the visual state.
(Rationale: Short, elegant, two paragraphs of narrative flow. Fully explains the problem and high-level solution without rigid, repetitive structural overhead.)
Context: Dynamic metadata footers serve as vital integration links connecting code changes to issue tracking systems, code review platforms, and automated release auditing pipelines.
| Rule ID | Principle / Constraint | Priority | Primary Symptom / Trap |
|---|---|---|---|
| T3-01 | Mandatory Integration Footer Preservation | Critical | Modifying, corrupting, or dropping structured footers (Change-Id, Bug, or issue tracking keys) during edits. |
Rule: Always preserve all structured git metadata footers at the bottom of the commit message, matching the appropriate tracker style based on environment context.
What: Do not modify, corrupt, or drop system-critical footers such as Change-Id, Bug, or tracker reference keys during edits.
Applies To: Commit message footer block at the bottom.
Why: Code review platforms (such as Gerrit) track revisions strictly using the
Change-Idfooter. Deleting it detaches revision history or breaks integration webhooks. Similarly, issue tracking systems rely on matching keys (e.g.,Bug: <ID>,Closes #<ID>) to link code commits with project tickets.
Trap 1: Amending or rewriting the commit message and dropping the original metadata footers.
Don't:
Update system cache configs
Refactored memory size and cache duration parameters.
Do (Standard issue tracker format):
Update system cache configs
Refactored memory size and cache duration parameters.
Bug: Issue 12345
Release-Notes: skip
Change-Id: Iab12cd34ef56gh78ij90kl12mn34op56qr78st90
Do (GitHub/GitLab tracker format):
Update system cache configs
Refactored memory size and cache duration parameters.
Closes #1234567
Release-Notes: skip
Change-Id: Iab12cd34ef56gh78ij90kl12mn34op56qr78st90
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