Execute Phase

Step executor for units. The unit doc (created by unit-lane) owns Tasks P1…Pn, Evidence rows, and a Progress log — these replace PLAN.md, TASKS.md, progress.md, and ACCEPTANCE.md. Each step runs as an atomic gate/commit.

Argument resolution (first match):

• <NN-slug> P<k> — exactly the step named by the triage order (P1, P2, …)
• <NN-slug> (no step) — all remaining steps, one commit each
• P<k> alone — the step by position in the current unit (last-known NN-slug)

Never infer a step ID absent from the triage block in the unit doc.

Turn contract

Tick every box before ending the turn; an unchecked box means the turn is not done:

✓ Required user inputs were answered concretely (not defaulted). Nothing here
  is inferred: a gap runs `bun scripts/needs-input.mjs <unit-dir>` (node fallback
if bun is not installed) and the
  `open-questions@1` block is pasted, then the run stops.
✓ Tool choice re-made this turn — `bun` before `node` on manual invocation,
  `rg` before `grep` on search; availability checked once with
  `node scripts/setup-env.mjs --check` (node and grep stay the documented fallback)
✓ Triage verified — unit doc Evidence section header matches
  `bun scripts/unit-route.mjs --triage <slug>` output block (PREFLIGHT.md)
✓ Unit doc read and step selected (explicit P<k> or first unfinished)
✓ Step executed and committed (one commit per step, conventional format)
✓ Test impact derived — the phase's test set came from the hint's block
  (TEST_IMPACT.md), and a prose-only phase recorded its `empty` verdict
✓ Evidence rows updated (command → exit/digest → output → verified-by)
  — each row carries the command, observed output (reproduced, not typed by
  hand), and the verifying-by credit. (S5 — claim-evidence loop: mandatory
  reproduction, loop-until-green inside the same turn)
✓ Progress log updated with a dated `YYYY-MM-DD HH:MM` entry that names the
  phase id (what, commit, next)
✓ Memory boundary ran — the phase's outcome saved under `unit/<NN-slug>/doc`,
  or the mirror marked pending when the layer is degraded
✓ Diff guard passed (on implement steps) — see `diff-guard` in PREFLIGHT.md
✓ Self-audit box (S9 d): every claim the persist introduces was re-derived
  with pasted output before the commit lands.
✓ → Next: block printed as the absolute last output

When to use

• A triaged unit from unit-lane: steps include implement/tests/evidence → invoke with <NN-slug> or <NN-slug> P<k>.
• Docs-only units (triage returns only [docs, evidence]) do not load this skill — they are executed in-place by the unit-lane conductor.
• To execute all remaining steps: <NN-slug> with no step argument.
• To repair a failed step: <NN-slug> P<k> (retry the same step).

Inputs — artifacts, never questions

This skill never interviews. It reads its inputs — the unit doc's Tasks, unit-route.mjs --triage's block, the route's tier — and a missing or ambiguous one is a gap, resolved in one fixed order and never by inference: (0) provenance (search the repo's own docs and record where) → (1) research (2–3 concrete options with trade-offs; asking for more research is a legitimate answer) → (2) halt: run bun scripts/needs-input.mjs <unit-dir> (node fallback if bun is not installed), paste the open-questions@1 block verbatim, stop. Interactive the block is the pause point, unattended it is a hard fail. Grammar and exit codes: orchestration-envelope's references/TURN_CONTRACT.md §Open questions.

Bare <NN-slug> runs all remaining steps — the phase is not an input. File targets are the unit doc's nested Relevant files: metadata plus the path-protection checkpoint. --max-attempts N defaults to 3; --force skips the stop on the dependency and phase-lint gates (never the check — PREFLIGHT.md records the override in the Progress log) and has no bypass on the path-protection checkpoint.

Step 0 — Discover the project

Per the agent guide's Workflow conventions + documentation map, read the unit doc at docs/features/<NN-slug>/SPEC.md. Verify it carries ## Tasks (P1…Pn) and the receipt sections of the shape it is written in (#308 accepts both): the legacy shape carries ## Evidence + ## Progress log, a re-cut unit doc carries ## Specs, ## Findings + ## Log (its evidence and gate runs are E/G log lines, its progress is P lines). If neither pair is present, the unit is not ready — stop and suggest unit-lane triage first. scripts/unit-route.mjs resolves the shape; never judge a re-cut unit by the legacy headings and stop it.

Process

1. Verify triage currency

Run bun scripts/unit-route.mjs --triage <slug> and compare its block to the Evidence section header in the unit doc. Mismatch → STOP and re-triage first. This is the gate that ensures the executor and unit-lane agree on steps.

2. Select the step

If a step argument is given (e.g. P2), use that step. Otherwise, the first unfinished step — the first P<k> in Tasks whose checkbox is unticked. Never execute a step the triage skipped.

The ceremony belongs to the risk tier (risk-tiers.md owns that table). A phase never lowers its own tier.

3. Pre-step gates

Run gates in order; any fails → STOP (see PREFLIGHT.md):

1. Path-protection checkpoint — read the committed range against protected paths (e.g. tests/, fixtures/). Exit 1 → STOP with the gate rejection block. No --force bypass (no flag can override).
2. Phase-lint — run bun scripts/phase-lint.mjs <unit-doc> only when the step is implement and the unit has Tasks P1…Pn. Parse the Tasks section (not PLAN.md/TASKS.md). Exit 1 → STOP. If the script is absent, apply the eight phase-contract rules by hand, label weaker, and disclose.
3. Pre-write mapper — for implement steps, settle the pre-write mapper contract before branch creation, planning commit, or source/test edit (references/PRE_EXECUTION_GATE.md): it closes the seven evidence questions and routes READY | REPLAN | NEEDS-DESIGN | BLOCKED; only READY authorizes the first write.
4. Dependency/invariant checks — per unit-lane's triage catalog rules: ensure required dependencies are merged; architectural invariants preserved or backed by an explicit recorded decision (block violates/introduces/ changes before edits).

4. Execute the step

Follow the unit-lane reference for this step (references/STEPS.md catalog): one line — read the step's reference file, perform its checklist, commit the work. For implement steps: derive the test set first (TEST_IMPACT.md owns the block and the RED-evidence shape) and write tests-first where they pay (core/domain, orchestration) — a new script+suite pair lands red-first: suite commits red (observed failing, naming the targeted suite), implementation green; UI/adapter glue may test after.

5. Claim-evidence loop (S5 — before post-step)

Before running post-step, verify every claim the step's repair introduces. This is the repairer-owned verification that prevents the unit 79 F50-class failure (closed gate-green with an unreproduced figure "170" without re-deriving via git diff --numstat).

1. Claim ledger. Enumerate every claim: each new figure, cross-reference, "X is now Y"; in code: each behavior the step declares.
2. Mandatory reproduction. Re-derive the figure with the command, resolve the reference with grep, reproduce the behavior. Paste command + observed output into the claim table — never type the expected result by hand.
3. Loop until green. red → repair → re-run, inside the same turn, until every claim verifies.
4. Admission rule. If no command can verify the sentence, it is not a claim, it is an opinion, and it does not get written.

Output:

| claim | command | output | status |
|---|---|---|---|
| <claim> | `<command>` | `<observed output>` | ✓ |

The row shape is published grammar (evidence-row@1 in @gtrabanco/agentic-workflow-schema), so a row missing its command, its observed output or a ✓/✗ verdict is a shape violation rather than a style nit.

Bounded checkpoint (S13/S14). The claim-evidence loop is only paid if it is cheap: bun scripts/test-route.mjs --check <changed path> names the minimal suite a path needs, so an intermediate verification costs seconds instead of the full gate. An unmatched path answers route: full-suite — never fewer tests — and the full gate stays what the merge gate and CI run.

6. Post-step

1. Diff guard (implement steps only): run bun scripts/diff-guard.mjs --base <last-step-commit> --unit <unit> — paste the block verbatim. BREACH → STOP (re-triage or record exception). Anti-gaming: NEVER shrink a diff by deleting comments, blank lines, docs or tests.
2. Evidence rows: one row per AC satisfied — | AC | command | exit/digest | output (≤2 lines, reproduced via command, not typed by hand) | verified-by | — append to the Evidence section. The evidence row is a reproduced receipt, not an assertion (S5: mandatory reproduction extends to doc artifacts).
3. Progress log: append a dated entry — YYYY-MM-DD HH:MM — <what was done> → <commit sha> — next: <what is next>.
4. Memory boundary — this step is a phase transition. Follow the memory protocol: before the first memory read run agentic-workflow memory probe once and record its verdict in Evidence; after the step, save the phase id, what it changed, its Evidence outcome and any discovery under topic_key: "unit/<NN-slug>/doc", an explicit project and explicit session attribution (§5). A degraded verdict is recorded and the mirror marked pending — it never blocks the step.
5. Commit: git add <changed files> then git commit -m "<type>(<scope>): <step-summary>" — run it, paste the SHA.

7. Red gate (repair loop)

After each step: run the project's verification gate (type-check + tests + build).

• Gate green → proceed.
• Gate red → record exit code + failing test names in the Progress log, repair the same step, retry. Default --max-attempts 3 (user value overrides).

• Exhausted → STOP with:

  UNIT LOOP — <unit> BLOCKED at <P<k>>
  Reason: <NO-PROGRESS|ATTEMPT-BUDGET> · Attempts: <n>
  Last validator: <command> → <exit/status + compact failure>
  Preserved: no red commit; acceptance blob <sha> unchanged
  
  → Next: inspect the named blocker, then re-run /execute-phase <unit> <P<k>>
    · architecture/product decision required → resolve it before resuming
    · continue atomically → /execute-phase <unit> <P<k>>

8. Whole-unit mode

When invoked as <NN-slug> with no step: loop all remaining steps, one commit each. This is an explicit operator choice only — the lane's hand-offs always name exactly one phase (<NN-slug> P<k>), so a bare <NN-slug> from a lane hand-off is a defect; re-read the hand-off before looping. After each step: gates, execute, diff guard (if implement), evidence/progress update, commit. Skip intermediate review checkpoints; the mandatory end review covers the full accumulated diff. On gate red at any step: repair that step (up to --max-attempts), then continue the loop. The close-out is part of the last step's completion: open the PR on main with Closes #N, write - PR: <url> into References, and settle the index row with agentic-workflow roadmap <index> rowUpsert '<json>' (docs/ROADMAP.md; a fix unit edits its row in that document's ## Fixes table — no NN column, no rowUpsert). bun scripts/roadmap-settle.mjs exits 0 (#316). Terminal:

UNIT LOOP — <unit> COMPLETE
Steps: <n> · Commits: <sha list> · Gate: PASS
PR: <url>

→ Next: /review-change on the changed HEAD — the mandatory end review
  · findings (REVIEW-FAIL) → /fold-findings repairs them; a fresh /review-change follows the fold
  · merge gate after REVIEW-PASS → /audit-pr

9. Descope guard

Before creating any issue while executing: classify with the descope test. A descope (moving an acceptance criterion or task out of scope) requires explicit user approval first, then record in the unit doc's ## References section (not a follow-up issue) as: - <YYYY-MM-DD> — descoped: "<criterion>" — approved by user. An issue may never be the first record of a descope.

Required references

These files must be loaded when their topic is active:

• PREFLIGHT.md — all gate blocks (dependency, status, pre-exec, evidence, lint, path-protection)
• TEST_IMPACT.md — the impact set, its block, the empty-impact verdict and the RED-evidence shape
• EXECUTION_CONTRACT.md — step completion gate, architectural invariants
• PRE_EXECUTION_GATE.md — pre-execution review gate, normalizer order
• FOLDING.md — review finding fold cycle
• DESCOPE.md — descope test and amendment rule
• FORGE_BODY.md — forge operations (gh body-file rule)

Guardrails

• The all-stages no-assumption rule binds every step here — ask-don't-infer, owner skills/unit-lane/references/DESIGN.md (ask-dont-infer@1): an expectation the tree, the docs, or a prior owner decision does not evidence is asked, never invented.

Allowed:

• Only the triaged steps listed by the unit doc's Evidence header
• Changes scoped to the acceptance criteria and step tasks
• Documentation updates in the unit doc (Evidence, Progress, References)
• Conventional commit messages per the project's Workflow conventions
• The step's own reference file (read one-hop from the unit doc catalog)

Forbidden:

• Never commit red (test failure) — fix within the step's scope, or record the blocker and stop.
• Never weaken a validator (loosen assertions, reduce coverage) — a repair must keep assertions at least as strong.
• Never execute a step the triage skipped — the catalog is authoritative.
• Never edit the unit doc's Acceptance criteria (that is re-triage with user consent).
• Never write to docs/LOGS.md (S9 4b): LOGS.md must be pure code output — no model writes it. The journal is append-only: a wrong past line gets a new correcting line, never an edit. Machine-authored git-facts entries (the extension's autoLogSession: mechanical, #394) also kill the "hand-tallied figure" class.
• Self-audit box (S9 d): before committing, re-derive every claim the step's persist introduces with pasted output. The turn does not end with unreproduced claims.
• Never expand scope beyond what Non-goals define — findings discovered during implementation never widen the unit.
• Never invent an acceptance criterion — ask the user with concrete options.

Relationship to other skills

unit-lane conducts (triage → judgment steps → close-out ladder) and hands execution off one phase per turn (<NN-slug> P<k> with the catalog tier); this executes the named phase — or, as an explicit operator choice only, all remaining steps. The closing hand-off names exactly one phase and the tier while phases remain, and resumes the lane after the last one. A phase run as a pi-web Relay leg is this same contract and nothing more (owner: unit-lane/references/RELAY.md): it runs one named phase, records the same evidence and progress lines, then hands the packet's baton to the next leg instead of resuming the lane. fold-findings handles review finding repairs. The review pack axes (review-implementation, review-code, review-security, review-perf, review-a11y, review-debt) compose the review step; workflow-status routes here. triage-issue feeds issues into the lane. This skill is the step executor a turn invokes to perform one triaged step of a unit under the full gate machinery.

Portability (agents other than Claude Code)

• No slash menu — open this SKILL.md and follow it literally in a fresh conversation. Where it says run, execute the shell command directly.
• No model tiers — triage and review use the strongest model; execution steps may use cheaper. Never review with a weaker model than the author.
• No /loop/subagents — invoke <NN-slug> for all remaining steps (the built-in loop), or <NN-slug> P<k> for individual steps.
• No fresh workers — execute inline and reduce state to the unit doc after each commit; never re-read prior files.

Done when

• Requested scope is implemented (the named phase, or all remaining steps in an explicit operator run), gate is green, unit doc Evidence/Progress are current (the Progress entry names the phase id), and the work is committed.
• The closing → Next: block is printed.

Closing recommendation

Exactly one end-state applies — pick by the unit's Tasks section, never print a phase id the Tasks section does not define:

Phases remain:

→ Next: /execute-phase <NN-slug> P<k+1> (tier: <tier>) — one phase per turn; <tier> is the catalog's implement entry
  · whole-unit operator run complete → /review-change (mandatory end review)
  · findings (REVIEW-FAIL) → /fold-findings repairs them; a fresh /review-change follows the fold
  · merge gate after REVIEW-PASS → /audit-pr — the merge gate

The last phase just closed (a lane-run unit):

→ Next: /unit-lane <NN-slug> — resume the conductor for the remaining judgment steps
  · whole-unit operator run complete → /review-change (mandatory end review)
  · findings (REVIEW-FAIL) → /fold-findings repairs them; a fresh /review-change follows the fold
  · merge gate after REVIEW-PASS → /audit-pr — the merge gate