Codd Impact

CoDD Impact Analysis

Use this skill after a requirements, design, code, or test change to determine what CoDD artifacts must be updated next. The goal is not only to read the impact report, but to decide whether the AI should update design documents immediately, ask a human for approval, or only report informational findings. Treat the impact report as an action queue for keeping requirements, design, implementation, and tests coherent.

Primary Command

Run impact analysis from the project root:

codd impact --path .

By default, this detects uncommitted changes (compares working tree to HEAD). No need to commit first.

If you need a report file:

codd impact --path . --output "codd/reports/impact_$(date +%Y%m%d_%H%M%S).md"

If you need to compare against a specific commit instead of uncommitted changes:

codd impact --diff <commit-hash> --path .

Preflight

1. Confirm you are at the project root and codd/codd.yaml exists.
2. Confirm codd/scan/ directory exists (contains nodes.jsonl and edges.jsonl).
3. If codd/scan/ is missing or empty, run:

codd scan --path .

4. Run codd impact --path ..
5. Read the report in this order:
   • Convention Alerts
   • Green Band
   • Amber Band
   • Gray Band

How To Act On Each Band

Convention Alerts

Convention Alerts have higher priority than Green, Amber, or Gray items. They mean an implicit rule may have been violated.

When a Convention Alert appears:

1. Open codd/annotations/conventions.yaml.
2. Find the rule that matches the reported target and reason.
3. Identify which invariant is being protected and which changed artifact triggered it.
4. Update the affected design docs, tests, or governance docs so the invariant is either preserved or explicitly re-decided.
5. If the business rule itself changed, do not silently override it. Ask the human to confirm the convention change before editing conventions.yaml.

Green Band

Green Band means the impact is high-confidence and the AI may update affected design documents autonomously.

Action:

1. Open each affected design document reported in Green Band.
2. Read the changed source artifact and the impacted design document together.
3. Update the impacted document's frontmatter if dependencies, conventions, or data dependencies changed.
4. Update the body to reflect the new behavior, interface, data flow, constraints, acceptance criteria, or verification approach.
5. Save the document.
6. Run codd scan --path . to rebuild the graph after the document update.
7. Re-run codd impact --path . to confirm the remaining impact set is reduced or reclassified.

Use Green Band for autonomous propagation. Do not wait for human approval unless the change introduces a product decision that is not already justified in the source requirements or governance docs.

Amber Band

Amber Band means the impact is plausible but requires human confirmation before the AI edits the affected document.

Ask the human with this template:

{設計書名}が影響を受けています。更新しますか？（変更内容: {変更サマリ}）

Action:

1. Summarize why the document is impacted.
2. Quote the document name and the change summary in the template above.
3. Wait for confirmation before editing the document.
4. If approved, update the document, run codd scan --path ., then re-run codd impact --path ..