TRIP-2-implement

Implementation Mode

You are now in implementation mode for [PROJECT_NAME].

Prerequisites - Read First

Before implementing, you MUST read ALL THE LINES of:

1. @docs/ARCHI.md - Understand current system architecture

Your Task

Implement: $ARGUMENTS

Step 0: Create a Branch (Pre-Implementation)

Always create a dedicated branch before implementing — no need to ask. TRIP-3-release merges it back into the main branch with fast-forward, keeping a single clean linear history.

git checkout -b feat/[short-description]   # or fix/[short-description]

Derive the short description from the plan/feature name. If already on a dedicated branch for this work (e.g., resuming a session), continue on it.

Implementation Phase — Delegate to Codex

You do NOT write the implementation yourself — delegate it to Codex via the codex-implement skill. (Exception: trivial unplanned changes of a few lines may be done directly.)

Delegation is batched: Codex implements a few of the plan's checkboxes per turn, you review and fix each batch, then request the next one with your corrections attached. Same persistent thread throughout — context and conventions compound across turns.

1. Read the plan and decide the batches

Read the plan fully and split its to-dos into batches. You are the judge of batch size:

• A batch is the smallest set of checkboxes that leaves the tree green (compiles, lints). Never split an interface from its implementation and wiring.
• The plan is likely sliced vertically: batch within the plan's phase order, never spanning phase boundaries; where possible, prefer a batch that completes a thin end-to-end path over one that builds out a single layer.
• Target a reviewable diff — roughly ≤300 changed lines per batch. A checkbox that alone exceeds this becomes its own batch.
• Size by risk: novel, architectural, or security-critical work → small batches (down to one checkbox). Mechanical, repetitive work → larger batches.
• One-shot escape hatch: a low-risk plan (or phase) of ≤3-4 checkboxes is delegated whole — no batching ceremony.
• Filter out non-Codex items: checkboxes needing human input, dashboard/console access, credentials, or ops actions are yours — resolve them with the user before or between batches, never delegate them.

2. Delegate batch by batch

Start the session with the first batch (state dir is handled by the script):

bash .claude/skills/codex-implement/scripts/start.sh \
    --prompt-file .claude/skills/codex-implement/prompts/implement.tpl \
    <plan-path> "Implement only: <batch-1 checkboxes>"   # or omit instructions to one-shot a small plan

Each next batch resumes the same thread, carrying your review corrections as --notes:

bash .claude/skills/codex-implement/scripts/resume.sh \
    --prompt-file .claude/skills/codex-implement/prompts/continue.tpl \
    --notes "<what you fixed after the last batch and why; conventions to apply from now on>" \
    <plan-path> "Now implement: <next batch checkboxes>"

Parse the trailing tag of each report:

• IMPLEMENTATION_COMPLETE → review the batch (below).
• IMPLEMENTATION_PARTIAL → read the report; resume with instructions for the remainder, or finish small leftovers yourself during the batch review.

3. Review each batch (delta review)

After each Codex report, before requesting the next batch:

1. Review the delta only: git status -s && git diff — worktree vs index shows just this batch, since previous batches are staged (step 4). Check it against the plan, ARCHI.md patterns, and project conventions (DRY, KISS, comment discipline, error-handling and naming conventions from ARCHI.md).
2. Fix problems directly yourself — no back-and-forth with Codex over fixes. What you fixed and why becomes the --notes of the next resume.
3. Micro-gate: run the lint and typecheck/build commands from the Testing Gate (fast checks only — tests wait for the gate itself). Fix failures now.
4. Checkpoint: git add -A — stage the reviewed batch so the next delta review starts clean. No commits — history stays clean for release.
5. Verify the plan checkboxes Codex ticked match what the diff actually contains; cross any it completed but missed.

Adapt as you go: clean batch → grow the next one; heavy corrections → shrink the next one and spell out the fix pattern in the notes. If Codex ignores notes or repeats corrected mistakes late in a long session, reset the thread at the next batch boundary — the plan file plus a summary note rebuilds context.

4. Final pass

After the last batch, read the full feature diff once (git diff HEAD). Batch reviews catch local issues; this pass catches cross-batch drift — duplicated helpers, divergent naming, dead code left by course corrections. Fix directly.

The testing gate and Codex code review run once, after the final pass — never per batch. Proceed to the testing gate once you consider the implementation good for review.

Testing Gate

After implementation, before the Codex review loop. Any failure here blocks the loop from starting.

1. Lint, type-check & build

# [ADAPT_TO_PROJECT: Replace with actual lint/type-check/build commands during Init]
[LINT_COMMAND] 2>&1 | tee /tmp/_trip2-lint.txt
[TYPECHECK_COMMAND] 2>&1 | tee /tmp/_trip2-typecheck.txt

2. Run affected unit tests

[TEST_COMMAND] <pattern-for-affected-files>

Only the files/areas the change touched — never the full suite by default.

3. Integration impact check

If the change modifies an externally observable contract (API shape, UI selectors, auth behavior), exercise it with the project's integration/E2E tooling. Docs-only changes skip this.

4. Author missing tests

If the change adds new logic, write its tests now, guided by the plan's Test Impact section and the project's testing guide (see TRIP-test). If no new logic was added, skip this step.

Hard-to-cover code policy:

• Test observable behavior (inputs → outputs/persisted effects), never internal wiring.
• Mock-pain tripwire: if the mock setup grows longer than the test's assertions, stop fighting it — check the project's testing guide for a seam recipe; if none applies, skip the deep unit test and add one line to docs/4-unit-tests/COVERAGE-DEBT.md (path | why hard | escape plan).
• Critical-path floor: behavior touching auth, deletion, persistence, cost, or external request shape must keep at least one behavioral test or manual integration check — coverage debt may defer internal-path depth, never safety-critical behavior.
• Never hide untested code (no coverage-ignore comments, no config exclusions, no lowering coverage gates). Legacy modules outside the change scope are not a feature blocker — but record newly encountered risky gaps in the ledger.

5. Build the summary

Format: lint: clean | typecheck: clean | tests: N passed (M new)

Fix failures before starting the loop.

Codex Code Review

Always run the Codex code review after the testing gate passes — no confirmation needed.

Loop

The code-review wrappers pin their own state dir — no export needed:

1. Start:

   bash .claude/skills/codex-code-review/scripts/start.sh \
       --prompt-file .claude/skills/codex-code-review/prompts/start.tpl \
       <plan-path> "$GATE_SUMMARY"
   

   $GATE_SUMMARY is the testing-gate summary (lint | typecheck | tests). For unplanned work (no F_*.plan.md), pass a free-form label instead of a plan path.

2. Parse trailing tag: APPROVED -> synthesize. NEEDS_REWORK -> surface to user. REQUEST_CHANGES -> continue.

3. Address findings — quote each with file:line, read the actual code, fix legitimate ones, push back on incorrect ones. Critical/Major block approval; Minor/Suggestion are case-by-case.

4. Write implementer notes (1-3 sentences): which findings you fixed, which you pushed back on and why, any user decisions or environment limitations Codex should stop re-flagging.

5. Resume (re-run the testing gate first — lint, typecheck, affected tests — and build a fresh summary):

   bash .claude/skills/codex-code-review/scripts/resume.sh \
       --prompt-file .claude/skills/codex-code-review/prompts/resume.tpl \
       --notes "Fixed X. Pushed back on Y because Z." \
       <plan-path> "$GATE_SUMMARY"
   

   Loop to step 2.

6. No cap — keep iterating until Codex returns APPROVED.

Synthesize

Skip if loop converged on Turn 1 (state file already holds full review).

Turn-N state files hold only that turn's delta. After multi-round convergence, produce a consolidated review:

bash .claude/skills/codex-code-review/scripts/resume.sh \
    --prompt-file .claude/skills/codex-code-review/prompts/synthesize.tpl \
    <plan-path> "Today's date is YYYY-MM-DD"

Outputs PROMOTION_READY sentinel. <x.y.z> Version placeholder left unfilled (resolved during TRIP-3-release).

Edge case:

• User skipped Codex: no synthesis. The CR is written manually during TRIP-3-release: "Code review skipped — trivial change."

Operating Notes

Surface reviews verbatim. Keep edits scoped. If Codex repeats a finding, re-read carefully — you likely addressed an adjacent concern. Reset thread only if context is confused. The testing gate (lint, typecheck, affected tests) must pass before APPROVED.

Handoff to Release

After Codex converges (or is skipped):

• Cross the corresponding checkboxes in the plan todo list (if any)
• Then use the AskUserQuestion tool to ask:
  • Question: "Is the implementation complete?"
  • Options: "Yes, everything is complete" (proceed to release), "No, there are remaining items" (continue working)

If "Yes": proceed directly into the release — read .claude/skills/TRIP-3-release/SKILL.md and follow it in this session, passing the same plan path (or feature label). The release skill owns everything from version bump to the fast-forward merge and push.

If "No": continue working, then repeat the sequence: testing gate → Codex review → this question.