/gig:implement Skill

Step 0 — Auto-Load Context

Read .gig/STATE.md and display: Version: {version} | Iteration: {iteration} | Status: {status}

If .claude-plugin/plugin.json exists, read the name and version fields and append to the header: | Plugin: {name} v{version}

If .claude-plugin/plugin.json does not exist, skip silently.

Step 1 — Guard Check

Read .gig/STATE.md, .gig/PLAN.md, and .gig/DECISIONS.md.

If status is NOT "GATHERED" and NOT "IMPLEMENTING": Say: "No approved plan found. Run /gig:gather first." STOP.

If all batches in the active iteration are done: Say: "All batches complete. Run /gig:govern to validate." STOP.

Step 2 — Set Up Git Branch

Reference: .gig/GIT-STRATEGY.md for full conventions.

If in a git repository and no feature branch exists for this iteration:

1. Check git status for uncommitted changes.
   • If dirty: Say: "Working directory has uncommitted changes. Stash or commit them before proceeding." STOP.
2. Create branch from main: git checkout -b feature/v0.{N}-{iteration-name}
3. If not a git repo, skip git operations but continue with state tracking.

If feature branch already exists (resuming), switch to it: git checkout feature/v0.{N}-{iteration-name}

Step 3 — Analyze Batch Dependencies

Before executing, scan all pending batches and classify:

• Independent batches — no dependency chain between them → candidates for parallel team execution.
• Dependent batches — must execute sequentially (in-session).

If 2+ independent batches are ready simultaneously, proceed with team mode (Step 4a). Otherwise, execute the next batch in-session (Step 4c).

Step 4 — Execute Based on Delegation Mode

4a — Team Mode (Parallel)

When 2+ independent batches are ready:

1. For each independent batch, use the Agent tool with isolation: "worktree". Each agent receives a prompt containing:
   • The batch description and work items from PLAN.md
   • Relevant ACTIVE decisions from DECISIONS.md
   • Working memory from STATE.md
   • Structural context from ARCHITECTURE.md (project stack, patterns, conventions)
   • Reference: .gig/GIT-STRATEGY.md for commit and branch conventions
2. Each agent works on an isolated branch: feature/v0.{N}-{iteration-name}/batch-{P}
3. After all agents complete, merge each task branch into the iteration branch: git merge feature/v0.{N}-{iteration-name}/batch-{P} — resolve conflicts if any.
4. Clean up after each merge:
   • Remove the worktree: git worktree remove {worktree-path}
   • Delete the task branch: git branch -D feature/v0.{N}-{iteration-name}/batch-{P}

If a team agent fails:

• Report the error and which batch failed.
• Ask the user:
  • Retry — relaunch the agent for that batch.
  • Fix in-session — execute the failed batch directly in the current session.
  • Skip — mark batch as skipped and continue (must address in governance).

If only 1 batch is ready, execute it in-session instead.

4b — Subagent Mode (Research)

• Use Agent tool with appropriate subagent_type.
• Feed findings into STATE.md working memory or dependent batches.

4c — In-Session Mode (Sequential)

• Work directly in the current session.

Step 5 — Batch Verification

After completing a batch:

1. Run the batch's test criteria.
2. Check acceptance criteria.
3. If passes: mark batch done.
4. If fails: report what failed, ask user how to proceed (fix/skip/stop).

Step 6 — Batch Commit

If in a git repo and verification passed:

1. Stage specific files by name (never git add -A or git add .).
2. Commit with conventional format:

   {type}(v0.{N}.{P}): {batch description}
   

   For unplanned batches, add [UNPLANNED] to the commit body:

   fix(v0.{N}.{P}): {description}
   
   [UNPLANNED] — inserted during iteration {N} implement.
   

3. Per-batch commits give granular rollback.
4. Never force-push. Never rewrite history.

If not in a git repo, skip commit but still update state.

Step 7 — Update State

After each batch:

1. Update .gig/STATE.md:

   • Version: increment PATCH (0.{N}.{P})
   • Status: IMPLEMENTING
   • Last Batch: batch title
   • Last Updated: today's date
   • Plugin Version: if .claude-plugin/plugin.json exists, read its version field and update this row. Otherwise leave as —.
   • Add to Batch History
   • Update Working Memory with discoveries

2. Update batch status in .gig/PLAN.md from pending to done.

Step 8 — Auto-Continue

After a batch passes verification, show a brief status line and auto-continue to the next batch:

Batch {N}.{P} done — {batch title}. Continuing...

Do NOT stop. Do NOT prompt. Proceed directly to Step 3 for the next batch.

The user can interrupt at any time by typing. If they do:

• fix [thing] — Increment PATCH, tag [UNPLANNED], execute the fix, insert into PLAN.md, shift subsequent versions, resume.
• revise [decision ID] — Update DECISIONS.md (mark old AMENDED, append new as ACTIVE), assess impact on remaining batches.
• pause — Update STATE and stop.
• amend [REQ-X] — Tier 3 spec amendment. Pause execution and run impact analysis:
  1. Read .gig/SPEC.md and increment the version header (e.g., Spec v1.0 → Spec v1.1).
  2. Append amendment entry to the ## Amendments section:

     AMD-{N}: Tier 3 — {description of what changed}. Affected: {REQ IDs}. Reason: {why the change is needed}.
     

  3. Identify which pending batches reference the affected REQ IDs (trace via Decision → REQ mapping in DECISIONS.md).
  4. Present impact analysis and 3 resolution options:
     • Patch batch — adjust current/next batch to accommodate the change, continue implementing.
     • Re-gather — pause implement, return to /gig:gather with the amended spec. Re-evaluates all remaining decisions and batches.
     • Story-level re-eval — if the amendment affects a user story, flag all REQs under that story for re-evaluation. Broader than patch, narrower than full re-gather.
  5. Wait for user choice before proceeding.

If verification FAILS (Step 5): STOP and present the error:

Batch {N}.{P} failed verification. {What failed and why}

• Fix — attempt to fix the issue and re-verify.
• Skip — mark batch as skipped (must address in governance).
• Stop — save state and halt implementation.

Wait for user direction before proceeding.

Step 9 — Iteration Complete

When all batches are done:

1. Update .gig/STATE.md: set Status to IMPLEMENTED.
2. Say: "All batches implemented. Run /gig:govern to validate and complete the iteration."