implement

Take a technical design and turn it into working, reviewed code — slice by slice, test-first, with progress checkpointed to disk so a new session can resume exactly where the last one stopped.

Inputs

One of:

• A path to a tech design document
• "implement the design" — use the design settled in conversation context

If neither exists, stop and ask for the design first.

State persistence

State file: .octo/implement-state.json in the repository root (create .octo/ if needed; add it to .gitignore if not ignored — the state file is session machinery, never committed).

On startup, always check for this file first.

• Exists → read it, summarize progress, ask: "Found an in-progress implementation. Resume from where we left off?" Resume honors each slice's status; "no" means ask whether to start fresh (overwrite) or abort.
• Missing → start at Phase 1.

{
  "tech_design_path": "path or '(conversation)'",
  "branch": "feat/...",
  "updated_at": "RFC3339",
  "waves": [
    { "wave": 1, "mode": "sequential",
      "slices": [
        { "slice": 1, "title": "...", "status": "pending|in_progress|review|done|skipped",
          "acceptance_criteria": ["..."], "files_owned": ["..."],
          "tests_added": 0, "review_summary": "", "deviations": "", "commit_sha": "" }
      ] }
  ]
}

Update the file on every status transition (slice starts, enters review, done with commit SHA + review summary + deviations). Delete it when everything is done — a clean exit leaves no state behind.

Resuming: done/skipped skip; review re-runs or finishes the review; in_progress checks git log for partial commits and continues from them or restarts the slice; pending starts normally.

Phase 1 — readiness gate, then decompose

Readiness gate. Before slicing, verify the design is concrete enough to code from: every API has method + path + request/response shape, every schema has fields + types, every external call names its counterpart. If something is too vague to implement without guessing, list exactly what's missing and ask the user (use ask_user_question for each decision) — do NOT decompose on top of vague specs; slices built on guesses produce guessed code.