Semantic Commit

Semantic Commit

Contract

Prereqs:

• Run inside a git work tree (or pass --repo to target one explicitly).
• git available on PATH.
• semantic-commit available on PATH (install via brew install nils-cli).
• git-scope is optional; default summary mode falls back to git show when unavailable.

Inputs:

• Staged changes (git add ...) for semantic-commit staged-context; the staged set may come from the user, an existing index state, or

agent-selected pre-skill staging.

• Prepared commit message via stdin (preferred), --message, or --message-file for semantic-commit commit.
• Optional target repository via --repo .

Outputs:

• semantic-commit staged-context: prints staged change context in bundle|json|patch format.
• semantic-commit commit: validates message, optionally commits staged changes, and prints commit summary unless disabled.
• Optional recovery file from --message-out .

Exit codes:

• 0: success (including --validate-only, --dry-run, and help output).
• 1: usage or operational failure (invalid args, git command failure, hooks/conflicts, bad repo path).
• 2: no staged changes for commands that require staged input.
• 3: commit message missing/empty.
• 4: commit message validation failed.
• 5: required dependency missing (for example, git).

Failure modes:

• Not in a git repo and no valid --repo supplied.
• No staged changes (exit 2).
• No message provided in automation mode (exit 3).
• Message format invalid (exit 4).
• git commit failure (hooks/conflicts/signing/repo state) (exit 1).
• Summary helper unavailable (git-scope missing): warning emitted, fallback to git show.

Setup

• Run inside the target git repo, or use --repo to avoid shell cwd switching.
• Use only the entrypoints below; they are the stable interface for agents.

Use this skill for:

• User-staged or pre-existing staged changes.
• Agent-selected task changes after the agent has inspected the working tree and staged only the intended paths.

Use semantic-commit-autostage instead when the full working tree delta is intentionally in scope.

Commands (only entrypoints)

• Get staged context:
• semantic-commit staged-context [--format ] [--json] [--repo ]
• Commit / validate prepared message:
• semantic-commit commit [--message |--message-file ] [options]
• Useful options: --message-out, --summary , --no-summary, --validate-only, --dry-run, --auto-fix,

--automation, --repo, --no-progress, --quiet

• --auto-fix (opt-in) normalizes machine-fixable issues before validation: wraps body lines at 100 chars (whitespace break preferred,

codepoint hard-break for CJK / unbreakable runs), lowercases the header type / (scope), uppercases the first char of - bullets, inserts a missing blank line between header and body, and drops empty lines inside the body. Does not truncate over-length headers or repair structural header errors; those still exit 4.

• Do not call internal helpers directly; treat these commands as the only contract surface.

Workflow

Rules:

• Never run git add in this skill; commit only what the user has already staged.
• If the agent must select this task's changes, inspect git status/diff and complete selective staging before entering this skill.
• Build message intent from semantic-commit staged-context output only.
• Prefer explicit --repo when operating from another working directory.

Recommended flow:

1. Run semantic-commit staged-context --format bundle (or --json if your parser expects JSON only).
2. Draft the semantic message (type(scope): subject + optional bullet body).
3. Run semantic-commit commit --validate-only ... before committing to catch formatting errors early.
4. Optionally run semantic-commit commit --dry-run ... for staged/message sanity checks without creating a commit.
5. Run semantic-commit commit ... to finalize.
6. Capture and report exit_code, stdout, and stderr.

Follow Semantic Commit format

Use one of:

• type(scope): subject
• type: subject

Rules:

• Type must be lowercase.
• Header length must be <= 100 characters.
• If body exists: line 2 must be blank, and every body line must start with - followed by an uppercase letter.
• Each body line must be <= 100 characters.

Error handling matrix

• exit 2 (no staged changes): stop and ask for staging.
• exit 3 (message missing/empty): provide/repair --message or --message-file.
• exit 4 (validation failed): fix header/body format first; do not commit. For body line-length, bullet casing, header type/scope casing,

blank-separator, or empty-body-line failures, retrying with --auto-fix normalizes the message in-place. Over-length headers and structural header errors are not auto-fixable and must be rewritten by hand.

• exit 1 from commit: treat as operational failure and report stderr verbatim.
• git-scope warning only: not fatal unless summary is explicitly required to be git-scope.

Example

semantic-commit staged-context --format json

semantic-commit commit \
  --message-file /tmp/commit-msg.txt \
  --validate-only

semantic-commit commit \
  --message-file /tmp/commit-msg.txt \
  --summary git-show

Output and clarification rules

• On failure: include command, exit code, and stderr; do not claim success.
• On success: include command output (commit summary) in a code block.
• If staged context cannot disambiguate type/scope/subject, ask one concise clarification question before committing.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: graysurf
• Source: graysurf/agent-kit
• License: MIT

Install and usage instructions live in the source repository linked above.