# TRIP-2-implement > Implement a feature following TRIP plan - Skill: `pilastdigit/trip-2-implement` (Agent Skill) - Install (CLI): `npx skillmds@latest add pilastdigit/trip-2-implement` - Raw SKILL.md: https://api.skillmd.com/api/skills/pilastdigit/trip-2-implement/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: pilastdigit (https://skillmd.com/u/pilastdigit) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/pilastdigit/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. ```bash 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 bash .claude/skills/codex-implement/scripts/start.sh \ --prompt-file .claude/skills/codex-implement/prompts/implement.tpl \ "Implement only: " # or omit instructions to one-shot a small plan ``` **Each next batch resumes the same thread**, carrying your review corrections as `--notes`: ```bash bash .claude/skills/codex-implement/scripts/resume.sh \ --prompt-file .claude/skills/codex-implement/prompts/continue.tpl \ --notes "" \ "Now implement: " ``` **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 ```bash # [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 ```bash [TEST_COMMAND] ``` 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 bash .claude/skills/codex-code-review/scripts/start.sh \ --prompt-file .claude/skills/codex-code-review/prompts/start.tpl \ "$GATE_SUMMARY" ``` `$GATE_SUMMARY` is the testing-gate summary (`lint | typecheck | tests`). For unplanned work (no `F_*.plan.md`), pass a free-form label instead of a plan path. 2. **Parse trailing tag**: `APPROVED` -> synthesize. `NEEDS_REWORK` -> surface to user. `REQUEST_CHANGES` -> continue. 3. **Address findings** — quote each with `file:line`, read the actual code, fix legitimate ones, push back on incorrect ones. Critical/Major block approval; Minor/Suggestion are case-by-case. 4. **Write implementer notes** (1-3 sentences): which findings you fixed, which you pushed back on and why, any user decisions or environment limitations Codex should stop re-flagging. 5. **Resume** (re-run the testing gate first — lint, typecheck, affected tests — and build a fresh summary): ```bash bash .claude/skills/codex-code-review/scripts/resume.sh \ --prompt-file .claude/skills/codex-code-review/prompts/resume.tpl \ --notes "Fixed X. Pushed back on Y because Z." \ "$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 bash .claude/skills/codex-code-review/scripts/resume.sh \ --prompt-file .claude/skills/codex-code-review/prompts/synthesize.tpl \ "Today's date is YYYY-MM-DD" ``` Outputs `PROMOTION_READY` sentinel. `` 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.