Implement

Implement the plan at docs/specs/<YY_MM_DD_HH>_<name>/plan.md.

Plan Discovery

With $ARGUMENTS: resolve against docs/specs/ — look for docs/specs/<YY_MM_DD_HH>_<name>/plan.md using the full dated spec identifier.

Without $ARGUMENTS:

1. List all */plan.md files under docs/specs/
2. Extract the YY_MM_DD_HH prefix from each folder
3. Use the file with the latest timestamp prefix

Orchestration

Read the plan file first. Then decide based on plan size:

• 1–2 steps or trivial changes: implement inline (no sub-agent needed)
• 3+ steps, or steps spanning distinct areas of the codebase: spawn a developer sub-agent per major phase

When spawning a developer sub-agent, brief it with:

• The full plan text
• Which step(s) it is responsible for
• Relevant project rules (CLAUDE.md, any project rules directory) — code style and any domain-specific conventions
• Current file state / context it needs (read key files first and include excerpts)
• Whether any external tool the plan depends on (an editor, engine, or service with its own connection state) is available and connected
• For steps touching source code: write the test for the new behavior first so it fails against the current code, then implement until it passes — never disable or weaken an existing test to force a pass, fix the underlying code instead

After each sub-agent phase:

1. Relay its results and any errors to the user
2. Verify the work (check for errors, read changed files) before moving to the next phase
3. If a phase fails, diagnose and re-brief the sub-agent with the fix context — do not skip ahead
4. Mark each completed agent step in the plan file by changing - [ ] to - [x]

Pre-flight Checks

• Follow all project standards in CLAUDE.md and any project rules directory
• If the plan depends on an external tool or editor with its own connection/session state, verify that connection is live before starting. If it isn't, stop and ask the user to establish it first.

Completion

After all steps are done:

• If any changes touch source code: confirm tests were written test-first (red before green) for the affected logic and all pass
• Run the code-review skill (or /code-review if unavailable as a skill) on the changed files — present any concerns one by one and ask the user to approve each fix before applying it