Git commit Skill | Agent Skills

Git commit

Contract

| Field | Bound contract | |---|---| | Trigger | User asks to commit or save staged or unstaged changes, create a typed branch, or format history for changelog generation. | | Authority | Reversible local writes only: stage selected local files, create a local feature branch, and create local commits. Never push, publish, or mutate a remote. | | Side effect | Local working tree, local index, local branch refs, and local commit objects. Rollback: git reset --hard <prior-HEAD> discards new commits; git branch -D <created-branch> removes a branch this skill created. | | Done | Each logical concern is committed with a value-communicating message; git status confirms success; commit hashes and subjects are reported. History is parseable and auto-generates changelogs, SemVer bumps, and issue closes. |

Inputs

Current working tree state (git status, git diff HEAD): required, gathered by the skill.
Current branch and recent commit history (git branch --show-current, git log --oneline -10): required, gathered by the skill.
Resolved remote default branch (git rev-parse --abbrev-ref origin/HEAD): optional; falls back to gh repo view --json defaultBranchRef --jq '.defaultBranchRef.name', then to main.
Repo commit-message convention in already-loaded project instructions: optional; used directly without re-reading.
An issue or tracker number, when one exists: optional; prefixed into the branch name and referenced in the commit footer.
The target platform (GitHub or GitLab): required only when closing issues cross-repo or cross-project.
User decision on creating a feature branch in detached HEAD state: required only when the repo is in detached HEAD.

Procedure

Gather context: run git status, git diff HEAD, git branch --show-current, git log --oneline -10, and git rev-parse --abbrev-ref origin/HEAD 2>/dev/null || echo DEFAULT_BRANCH_UNRESOLVED. Strip the origin/ prefix from the default branch. If it returned DEFAULT_BRANCH_UNRESOLVED or bare HEAD, try gh repo view --json defaultBranchRef --jq '.defaultBranchRef.name'; if that also fails, use main. Done when: working tree state, branch, recent history, and default branch are known.
If git status shows a clean working tree (no staged, modified, or untracked files), report nothing to commit and stop. Done when: the working tree is confirmed clean and the skill stops, or changes are confirmed present.
If the current branch is empty, the repo is in detached HEAD. Ask whether to create a feature branch using the platform blocking question tool (AskUserQuestion in Claude Code, request_user_input in Codex, ask_question in Antigravity, ask_user in Pi); fall back to chat only when no blocking tool exists or the call errors, never for an unloaded schema. If yes, derive a typed branch name (Step 5), run git checkout -b <branch-name>, re-run git branch --show-current, and use it for the rest of the workflow. If no, continue with the detached HEAD commit. Done when: the branch decision is made and the branch is confirmed.
Determine the commit message convention in priority order: (1) repo conventions in already-loaded project instructions, used directly; (2) a clear pattern in the recent commits from Step 1 (conventional commits, ticket prefixes, emoji); (3) the seven-rule style: capitalized imperative subject, 50 chars target and 72 hard, no trailing period, blank line, body wrapped at 72 explaining what and why, never how. If source (1) or (2) uses conventional commits, format the subject as <type>(<scope>): <subject> (scope optional) and pick the most precise type from the allowed set with its SemVer effect: feat (MINOR), fix (PATCH), docs, test, build, ci, chore, style (formatting with no logic change), ref or refactor (refactoring with no behavior change), perf, meta (repository metadata), license, revert (none). Keep the subject ≤ 72 characters, imperative mood, no capital letter, no trailing period. Done when: the convention is determined and, if conventional, the type and SemVer effect are selected.
Name the branch <type>/[issue-]<description>: lowercase, hyphens only, no special characters except /. Prefix the issue number when one exists (feat/42-user-authentication). Keep the description under 50 characters. Match the type to the work. Done when: the branch name is lowercase, hyphen-separated, typed, under 50 chars.
Determine logical commits. One concern per commit, where a concern is one reason the tree changed. Put two changes in the same commit only when reverting one without the other leaves the tree broken. Split by mechanism, not by file. When one file carries two mechanisms, write the filtered patch out of git diff -- <file>, keep only the hunks for one mechanism, and stage it with git apply --cached <patch> (confirm this headless form on the first real split, since git add -p needs a TTY the agent lacks). A lint, format, or whitespace sweep is its own commit, never folded into a behavior change. Order commits so each leaves the tree building. A commit that only builds with its successor is not atomic, so merge the two or re-cut the split. Done when: commit groups are determined and ordered.
If the current branch is main, master, or the resolved default branch, automatically create a feature branch first: derive the typed name from Step 5, run git checkout -b <branch-name>, confirm with git branch --show-current, and use it for the rest of the workflow. Do not ask; committing on the default branch is not an option here. Done when: a feature branch is created and confirmed, or the current branch is already a feature branch.
For each commit group, run the repo-native verification gate (type-checker and/or linter, whichever it defines) before staging that group. A failing group is not ready to commit. Skip silently if neither is configured. Done when: each group passes its gate or the failing group is named and skipped.
Stage and commit each group in a single call. Prefer naming files over git add -A or git add ., which can sweep in sensitive files (.env, credentials) or unrelated changes. Write the subject concise, imperative, why not what, per Step 4's convention; add a body only when a future reader would need motivation or trade-offs. Mark breaking changes with ! after the type/scope or with a BREAKING CHANGE: footer so changelog tools detect the MAJOR bump; body-only descriptions are invisible to them. For revert, keep the This reverts commit <hash>. line that git revert generates. Close issues from the commit footer using a case-insensitive keyword (close(s/d), fix(es/d), resolve(s/d)) followed by the reference. On GitHub: Closes #42, Closes owner/repo#99, or Closes #42, closes #43; triggers on merge to the default branch. On GitLab: Resolves #101, Closes group/project#42, or Closes #101, closes #102. To link an issue without closing it, use Refs #42 (GitHub) or Refs #101 (GitLab). Never include customer or organization names, user emails, support ticket contents, secrets, or PII. Never add a Claude signature, AI agent attribution, or Co-authored-by trailer for Claude or any AI agent. Use a heredoc to preserve formatting:

git add file1 file2 file3 && git commit -m "$(cat <<'EOF'
feat: add first-class subject line here

Optional body explaining the change and why it was needed.

Closes #42
EOF
)"

Done when: each group is staged and committed with a value-communicating message. 10. Run git status after the commit to verify success. Report the commit hash(es) and subject line(s). Done when: git status confirms success and hashes and subjects are reported.

Failure and recovery

Clean working tree: report nothing to commit and stop; no mutation occurs.
Detached HEAD with no branch decision: stop and report that a branch is required to attach the work; no commit is created.
Verification gate failure for a group: that group is not ready to commit; do not stage or commit it. Already-committed groups remain; uncommitted groups are left unstaged. Report which group failed and the gate output.
Sensitive or unrelated file detected during staging: exclude it by naming files explicitly; never use git add -A or git add ..
Non-conforming branch or commit name: do not create or amend it. Correct the name in place (rename the branch with git branch -m, or rewrite the unpushed commit) and re-check against the format before proceeding.
Breaking change stated only in the body: add ! or a BREAKING CHANGE: footer; do not rely on body text.
Issue reference placed in the subject line: move it to the footer and re-verify the keyword and reference syntax for the target platform.
Any mutation that has already been pushed: stop and surface the pushed ref rather than force-rewriting shared history.
Partial result: groups already committed are real commits and remain; the blocked result names the uncommitted groups and the failure reason. Rollback for a created feature branch is git branch -D <branch-name>; rollback for new commits is git reset --hard <prior-HEAD>.
Never swallow a git error or report the done predicate when git status does not confirm success.

Output

Local commits (one per concern, each with a conventional-commits message carrying SemVer effect and issue-closing footers) on a typed local branch, plus a report of hash(es), subject line(s), and confirming git status. History is parseable so tooling can auto-generate changelogs, enforce SemVer bumps, and close referenced issues on merge to the default branch.

Agent Skills: Git commit