# AI Attribution Governance: Enforcing AI Disclosure Policies at the CI Level

The open-source ecosystem is converging on a hard question: **when a commit is
written with AI assistance, how do we know — and how do we enforce the
disclosure policy?**

Python's discourse, Linux kernel's `Assisted-by` trailer, Fedora's AI policy,
Apache's disclosure guidelines — every major project is grappling with this.
But until now, there has been **no tool at the CI level** to enforce whatever
policy a project chooses.

Commit Check v2.11.0 introduces **AI Attribution Governance** — a
new feature that detects known AI tool signatures in commit
messages and lets projects decide whether to forbid them outright.
To our knowledge, no existing tool enforces this kind of policy at the CI
level.

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## The industry need

The conversation around AI disclosure is no longer theoretical:

- The **Linux kernel** standardized on the `Assisted-by:` trailer format — but deliberately stopped short of CI enforcement. As Sasha Levin noted at the Maintainers Summit, the kernel sets the convention, not the gate.
- The **Python community** [is actively discussing](https://discuss.python.org/t/should-claude-codes-usage-be-described-in-the-code-docs-somewhere/107969) whether Claude Code usage should be documented
- **VS Code** [issue #313962](https://github.com/microsoft/vscode/issues/313962) proposes replacing `Co-authored-by` with `Assisted-by` for AI agents
- **Fedora** requires AI disclosure (recommends the `Assisted-by` trailer). **QEMU** and **Gentoo** go further and **forbid** AI-generated contributions entirely.

Each community defines its own policy — but none provides a neutral
enforcement layer. That is the gap Commit Check fills.

## Configuration: a single toggle

Commit Check keeps it simple. One configuration value, three ways to set it:

=== "TOML (cchk.toml)"

    ```toml
    [commit]
    ai_attribution = "forbid"
    ```

=== "CLI"

    ```bash
    commit-check --message --ai-attribution=forbid
    ```

=== "Environment Variable"

    ```bash
    CCHK_AI_ATTRIBUTION=forbid commit-check --message
    ```

Two modes:

| Mode | Behavior |
|------|----------|
| `"ignore"` | No validation (default, backward compatible) |
| `"forbid"` | Rejects any commit containing known AI tool signatures |

There is no `require` mode in this release — only `ignore` and `forbid`. The
reason is pragmatic: requiring a `Assisted-by` or similar trailer is a
substantially harder problem (validating semantics, not just pattern-matching),
and the most immediate demand from projects is the ability to say **no**. The
kernel and Fedora communities that want `require` are on the roadmap (see
[What's next](#whats-next)).

## Detected AI tool signatures

Commit Check ships with a curated database of known AI tool markers. The
detection covers multiple signature formats per tool — `Co-authored-by`,
`Assisted-by`, body markers, and model names:

| AI Tool | What gets detected |
|---------|-------------------|
| **Claude Code** | `Co-authored-by: Claude`, `Assisted-by: Claude:<model>`, emoji markers, `Claude-Session:`, `Claude-Workflow:` |
| **GitHub Copilot** | `Co-authored-by: Copilot` |
| **OpenAI Codex** | `Co-authored-by: Codex` |
| **Gemini** | `Co-authored-by: Gemini` |
| **Cursor** | `Co-authored-by: Cursor` |
| **Devin** | `Co-authored-by: Devin` |
| **Aider** | `Co-authored-by: Aider`, `Co-authored-by: ... (aider)` |
| **Windsurf** | `Co-authored-by: Windsurf` |
| **Tabby** | `Co-authored-by: Tabby` |
| **Generic AI** | `Assisted-by: <tool>:<model> [tools]`, model names like `claude-sonnet-4`, `gpt-4-turbo` |

## Built-in false positive prevention

A `Co-authored-by: Claude` could theoretically be a human named Claude — but
in practice, AI tools use known noreply email addresses. Commit Check anchors
its detection to these, so:

🚫 `Co-authored-by: Claude <noreply@anthropic.com>` — **detected**  
🚫 `Assisted-by: Claude:claude-sonnet-4-20250514 [tools]` — **detected**  
✅ `Co-authored-by: Claude Monet <monet@impressionism.fr>` — **ignored**  
✅ `Co-authored-by: Jane Doe <jane@example.com>` — **ignored**

The kernel-style `Assisted-by:` format also handles optional trailing tool
lists correctly:

```text
Assisted-by: Claude:claude-sonnet-4-20250514 coccinelle sparse
```

Only the AI tool marker is matched — the tool list is preserved as-is.

## See it in action

With a config file containing `ai_attribution = "forbid"`:

```bash
# This commit message would be REJECTED
echo "fix: resolve race condition

Co-authored-by: Claude <noreply@anthropic.com>" | commit-check -m
```

```text
[FAIL] ai-attribution: Commit message contains known AI tool signature: Claude
```

```bash
# This commit message passes cleanly
echo "fix: resolve race condition

Co-authored-by: Jane Doe <jane@example.com>" | commit-check -m
```

```text
[PASS] commit message is valid
```

## Integration across the ecosystem

The feature is available across nearly every surface of Commit Check:

- **CLI**: `--ai-attribution=forbid`
- **TOML config**: `[commit] ai_attribution = "forbid"`
- **Environment variables**: `CCHK_AI_ATTRIBUTION=forbid`
- **Python API**: `validate_message()` returns AI attribution results
- **`--format json`**: AI check status included in structured output
- **MCP Server** ([commit-check-mcp](https://github.com/commit-check/commit-check-mcp)): synced in v0.1.7
- **GitHub Action** ([commit-check-action](https://github.com/commit-check/commit-check-action)): coming in the next release

## Scope and limitations

AI Attribution Governance detects the **default behavior** of AI coding tools
— the trailers, markers, and metadata they add automatically. It is not
designed to catch intentional circumvention. If a developer manually removes
the AI signature before committing, this feature will not flag it.

This is the same trust boundary that every linter operates within:
`--no-verify` bypasses pre-commit hooks, and a determined author can always
rewrite history. The goal is to **set a visible, enforceable policy** for the
standard case — making AI disclosure the path of least resistance — and leave
intentional evasion to code review and engineering culture.

## What's next

AI attribution governance in v2.11.0 is the foundation. Future work includes:

1. **`require` mode** — reject commits that are missing an `Assisted-by`
   trailer, serving projects like the Linux kernel and Fedora that mandate
   disclosure
2. **PR summaries** — show AI disclosure status per commit in pull requests
3. **MCP improvements** — AI agents query `describe_validation_rules` to
   auto-comply before writing a commit
4. **Richer JSON metadata** — structured AI signature data for SBOM and audit
   tooling

## Try it today

```bash
pip install commit-check==2.11.0
echo "feat: add streaming support" | commit-check -m --ai-attribution=forbid
```

Or add it to your `cchk.toml`:

```toml
[commit]
ai_attribution = "forbid"
```

And let CI enforce your AI disclosure policy — automatically, on every commit.