implement

name	implement
description	End-to-end workflow for taking MCP work items from backlog to merged PR. Handles git branching, schema-driven planning, implementation, independent review, and PR creation. Composes spec-quality, review-quality, and schema-workflow skills into a single pipeline. Use when a user says "implement this", "work on this item", "fix these bugs", "pick up the next task", "create a PR for this", "go through the backlog", or references specific MCP item IDs for implementation.
user-invocable	true

Implement

End-to-end workflow for taking MCP work items from queue to PR. This skill composes the schema-driven planning (spec-quality), implementation, review (review-quality), and git/PR workflow into a single pipeline.

Usage:

• /implement <item-id> — work on a specific item
• /implement — with context about what to work on
• Can process single items or multiple items in batch

---

Step 1 — Assess the Work

Load the item(s) and determine the execution tier and interaction mode.

For each item, call get_context(itemId=...) to understand:

• Current role and gate status
• Schema tag (feature-implementation, bug-fix, etc.)
• Existing notes already filled
• Dependencies and blocked status

Execution tier — classify by this table (canonical source shared with the Workflow Orchestrator output style; edit the fragment, not this copy):

Criteria	Tier	Pipeline
1-2 files, known fix, no migration/new API	Direct	Orchestrator edits, tests, reviews inline
3-10 files, single logical unit, clear or explorable scope	Delegated	Single subagent, separate review agent
11+ files, multiple independent work streams, dependency edges	Parallel	Worktree agents, full pipeline

Force-UP signals (bump tier regardless of file count):

• Database migration → min Delegated
• New public API surface → min Delegated
• Multiple independent work streams → Parallel
• User says "let's plan" / collaborative language → min Delegated

Force-DOWN signals:

• User says "just fix it" / "quick" → Direct (unless complexity contradicts)
• Schema tag is default or absent → eligible for Direct

If the item has no schema tag, apply quick-fix for Direct tier or leave untagged for Delegated/Parallel (the default schema catches these).

Trait application on classification. When the tier resolves to Delegated or Parallel and the workspace defines a delegated trait (it appears in availableTraits on create responses), apply it before any dispatch — traits: "delegated" at item creation, or manage_items(operation="update", items=[{itemId: "<uuid>", traits: "delegated"}]) for an existing item. This makes the orchestrator-filled delegation-metadata note schema-visible instead of convention-only. Direct tier: do not apply it — nothing is delegated.

Test-author trigger rule. bug-fix.default_traits already includes needs-test-author — no action needed, it applies automatically. For feature-task items, apply needs-test-author per item (manage_items(operation="update", items=[{itemId: "<uuid>", traits: "needs-test-author"}])) when acceptance criteria involve a predicate, algorithm, parser, validator, or state transition, or when any force-ON signal is present: new public API surface, a database migration, a security predicate, or a prior vacuous-test finding in this item's area. Other schema tags (feature-implementation, plugin-change, quick-fix, and the global floor) do not carry the trait. Direct tier: apply the trait only in its temporal-only degraded mode, and only on bug-fixes — the test-plan gate and red-first rule still apply, test-manifest declares a single actor, and there is no separate test-author dispatch. Other Direct-tier items are exempt regardless of the criteria above — the tier is too small to separate authorship into a second dispatch.

Interaction mode — orthogonal to tier:

Signal	Mode
User says "work with me on", "let's plan", or similar collaborative language	Collaborative — user participates in planning and key decisions
Scope is clear, no user participation needed	Autonomous — agent handles the pipeline
Unclear scope or ambiguous complexity	Ask the user

When processing multiple items, evaluate whether related items (e.g., bugs in the same module, fixes that touch the same files) should be grouped into a single branch and PR. Group when the changes are cohesive and independent fixes would create merge conflicts. Keep items separate when they're unrelated or when isolation makes review cleaner.

---

Step 2 — Prepare the Branch and Worktree

Sync local main before any implementation begins.

git checkout main
git pull origin main --tags

The branching/worktree strategy depends on tier:

Direct tier (orchestrator implements 1–2 files inline) — create a working branch on the main directory:

git checkout -b <branch-name>

Delegated tier (single subagent) — same as Direct: orchestrator creates the branch on the main directory, the subagent works against it. No worktree.

If the main checkout is unavailable (another branch checked out, uncommitted changes present) or the orchestrator itself runs from a worktree — Direct and Delegated tiers both: do not touch the occupied checkout. Create a dedicated worktree instead:

git worktree add .claude/worktrees/<slug> -b <branch-name> origin/main

Work there using absolute paths and git -C (never cd); after the PR merges, remove the worktree and delete the branch. Sync local main via git fetch origin main:main while main is not checked out anywhere, or a normal git pull from the main checkout when it is.

Parallel tier (parent feature with multiple children) — create a single feature worktree that all child agents share:

FEATURE_SLUG=<short-feature-description>          # e.g. issue-117-followup
FEATURE_BRANCH=feat/$FEATURE_SLUG
FEATURE_WORKTREE=.claude/worktrees/feat-$FEATURE_SLUG

# Resume detection — if the branch/worktree already exist (orchestrator restart
# mid-feature), reuse them rather than recreating:
if git show-ref --verify --quiet "refs/heads/$FEATURE_BRANCH"; then
  echo "Resuming existing feature branch $FEATURE_BRANCH"
else
  git branch "$FEATURE_BRANCH" main
fi
if [ ! -d "$FEATURE_WORKTREE" ]; then
  git worktree add "$FEATURE_WORKTREE" "$FEATURE_BRANCH"
fi

All child-task agents will be dispatched into this shared worktree (Step 4). The feature branch is pushed and PR'd once, when the parent feature reaches terminal (Step 6).

Why one worktree per feature, not per child: the feature is the natural PR boundary. Per-child PRs created cross-PR test contamination and PR-body staleness during the #117 follow-up (see retro a7f6024f). Shared worktree means one commit history, one CI cycle, one PR — and the parent feature's review-checklist gives a coherent point at which to finalize.

Branch naming:

• feat/<feature-slug> — feature-implementation parents (the integration branch)
• fix/<short-description> — bug-fix items (Direct or Delegated tier)
• fix/<grouped-description> — batch of related bug fixes (Delegated tier)
• chore/<short-description> — tech debt, refactoring (Direct tier)

---

Step 3 — Queue Phase: Planning

This step is tier-conditional:

Direct tier: Skip this step entirely. No plan mode. No queue-phase notes. Call advance_item(trigger="start") immediately to move queue→work. The quick-fix schema has no queue-phase required notes, so the gate passes. Exception: if the item carries needs-test-author (temporal-only degraded mode, Step 1), test-plan is a queue-phase note and must be filled before this advance — see the seat-timing rule below.

Delegated tier: Fill queue-phase notes per schema. Use get_context(itemId=...) to see expectedNotes and guidancePointer. Pre-plan-workflow is optional — use only if scope needs exploration. Post-plan-workflow only if child items need materialization. Advance: advance_item(trigger="start").

Parallel tier: Full planning pipeline:

Collaborative mode:

1. Tell the user the item is ready for planning and ask them to enter plan mode. The pre-plan-workflow and post-plan-workflow hooks fire automatically on plan mode entry and exit, handling context gathering and materialization.
2. During planning, follow the guidancePointer for each required note — this will reference the spec-quality skill where applicable.
3. After plan approval and post-plan materialization, advance the item: advance_item(trigger="start")

Autonomous mode:

1. Read and follow the pre-plan-workflow skill — gather existing MCP state, check schema requirements, and understand the definition floor.
2. Research the codebase — explore relevant files, understand current state.
3. Fill all queue-phase notes following the guidancePointer for each. The spec-quality framework applies regardless of mode.
4. Read and follow the post-plan-workflow skill — materialize child items if the plan calls for them.
5. Advance the item: advance_item(trigger="start")

The gate will reject advancement if required notes are missing. If rejected, fill the missing notes and retry.

Do not confuse this with resource-lease contention. A queue→work advance_item can also fail with applied: false, errorCode: "resource_unavailable", errorKind: "transient" — a resource a trait on this item declares (resources:) is currently held by another item. This is not a note gate failure: filling notes will not fix it. Work a different item and retry later (retryAfterMs is a hint), or report the contended key(s) to the user.

Seat timing for needs-test-author items. The queue-phase test-plan note is filled by the planning seat — the orchestrator (Direct tier) or the plan author (Delegated/Parallel tier), invoking the test-author skill's scenario-derivation and oracle-derivation sections — and this happens before advance_item(trigger="start") moves the item queue→work. This is by design: test-plan gates work entry, the same way any other required queue-phase note does. This is a distinct seat from Step 4b's test author seat, which writes test code and fills test-manifest at work phase — see Step 4b's intro for the two-seat distinction.

---

Step 4 — Work Phase: Implementation

Verification commands. Throughout this step, "run tests" means running BOTH the test suite AND the project linter:

./gradlew :current:test
./gradlew :current:ktlintCheck

CI enforces both — a green test run with failing lint will still block the PR. If ktlintCheck fails, run ./gradlew :current:ktlintFormat to auto-fix formatting violations, then verify with ktlintCheck again and re-run tests. Include both commands in every implementation-agent and review-agent prompt.

Who runs the lint cycle (proposal ee6f5d32, ~9 sessions of evidence):

• Delegated tier (agent owns gradle): the implementation agent runs the ktlintCheck → ktlintFormat → re-verify cycle itself before committing. Validated 2026-07-13 (PRs #213/#214/#215): zero orchestrator fix-up commits.
• Parallel tier (orchestrator owns gradle): agents include :current:ktlintFormat in their compile self-check (see the dispatch template below); the orchestrator additionally runs ktlintFormat before ktlintCheck after each commit batch — historically 3-5 fix-up commits per multi-phase run when skipped.

Capturing gradle's real exit code (use this pattern, not 2>&1 | tail -N). Piping gradle into tail discards gradle's exit code — tail always exits 0 on a successful read of the log, so BUILD FAILED at the end of the gradle output is reported by you as a successful run. Combined with gradle's daemon incremental cache, this can hide broken compilation through entire CI cycles (retro 568a8584: 9 silently-failing tests shipped on PR #151 before the followup audit caught it).

The reliable pattern, especially when running in run_in_background:

./gradlew :current:test > /tmp/gradle-out.log 2>&1; EXIT=$?
echo "EXIT=$EXIT"
tail -30 /tmp/gradle-out.log

Redirect ordering matters: use > /tmp/log 2>&1, NOT 2>&1 > /tmp/log — the latter is evaluated left-to-right and leaks stderr (where gradle writes compile errors) to the terminal instead of the log (retro ac25db89: a compileTestKotlin failure was invisible in the captured log until the ordering was fixed).

EXIT=$? captures gradle's actual exit code before any pipe consumes it. Read the captured exit code AND the tail of the log; never trust the tail alone. This applies to every orchestrator-owned gradle invocation throughout this step.

Use --rerun-tasks after dependency upgrades or large refactors. Gradle's incremental compile cache retains class files from prior good builds. After a gradle/libs.versions.toml bump or a refactor that changes public API surfaces (removed methods, renamed types, sealed-class arms, generic-parameter shifts), incremental compilation can keep the OLD class files alongside source that no longer compiles, producing apparent BUILD SUCCESSFUL on stale bytecode. Run ./gradlew :current:test --rerun-tasks once after such changes to force a clean run; ordinary incremental builds are safe afterwards.

This step is tier-conditional:

Direct tier: Implement directly. Edit the files, run the test suite. No subagent dispatch. No /simplify pass. Exception — a Direct-tier bug-fix carrying needs-test-author: follow Step 4b's Direct-tier test-first-then-fix sequence (test-plan frozen at queue → regression test observed red → fix → green) instead of implementing first. Fill the session-tracking note (required by both quick-fix and default schemas) with a brief summary of what changed and test results. Advance to review: advance_item(trigger="start").

Delegated and Parallel tiers: Use get_context(itemId=...) to see work-phase expectedNotes and guidancePointer values. Fill each required note following its guidance. Follow the delegation model from your output style (model selection, return formats, UUID inclusion). The key decisions at this step are:

• Single item (Delegated): delegate to one implementation subagent or implement directly. Subagent works in the main directory on the working branch.
• Multiple child tasks, independent (Parallel): dispatch parallel subagents into the shared feature worktree created in Step 2. Each agent receives the worktree path and branch name. Do not use isolation: "worktree" on the Agent tool — that would spawn a separate worktree per dispatch, which is the deprecated per-child PR pattern.
• Multiple child tasks, dependent: dispatch sequentially into the shared feature worktree. Wait for each agent's commit to land before dispatching the next.

Test-file ownership boundary. Every implementation dispatch (Delegated single agent or Parallel per-child agent) excludes src/test/** from scope — implementers do not create or modify test files. When a change surfaces a needed test update, the agent reports it in its return (or in implementation-notes) rather than editing the test itself; the test author (Step 4b) owns that file tree exclusively on items carrying needs-test-author.

Parallel dispatch into a shared feature worktree:

Agent(
  prompt="""
  Working directory: <feature-worktree-path>
  Branch (already checked out): feat/<feature-slug>
  Scope (modify ONLY these files): <explicit list>
  Do NOT create or modify any file under src/test/** — test authoring is a separate,
  independent dispatch (Step 4b) on items carrying needs-test-author. If your change
  surfaces a needed test update, report it in your return; never edit the test yourself.

  Format + compile self-check (REQUIRED before returning):
    ./gradlew -p <feature-worktree-path> :current:ktlintFormat :current:compileKotlin :current:compileTestKotlin > /tmp/agent-compile.log 2>&1; EXIT=$?
  If EXIT != 0, fix the reported error — a compile error OR a lint violation
  ktlintFormat could not auto-correct (e.g. line >140 chars, colons in backticked
  test names) — before committing and returning.
  Do NOT run :current:test or :current:ktlintCheck — orchestrator owns full build
  verification. ktlintFormat is formatting-only and idempotent; it prevents the
  recurring lint fix-up commits (proposal ee6f5d32). The compile self-check is
  fast (~3s) and catches type-mismatch /
  signature errors that gradle's incremental cache may otherwise mask in the
  orchestrator's later test run (retro `568a8584`: H3's `dbNow()` shipped with a
  Result<T> vs Instant return type mismatch that was hidden for ~6 hours).

  After self-check passes, commit your changes with a descriptive message.
  """,
  model="sonnet",
  subagent_type="general-purpose"
  // NOTE: no isolation parameter — agents share the feature worktree
)

File-edit overlap discipline: Parallel agents in a shared worktree must operate on non-overlapping files. The orchestrator scopes each agent's prompt to a specific file list (per MEMORY.md §"Parallel File-Edit Delegation"). When inherent overlap exists, dispatch sequentially.

Contract-change sweep discipline. When a child task tightens a contract — making a parameter required, adding validate() invariants, narrowing a sealed-class arm, or otherwise rejecting inputs that earlier passed — the orchestrator must sweep the rest of the codebase before advancing to review. Two recurrences (retros a7f6024f and 568a8584) showed that:

• Pre-existing test fixtures constructed under the old contract will fail under the new one. Example: H2's WorkItem.validate() claim-field invariants broke 8+ test fixtures that constructed mixed-state items via separate Instant.now() calls (microsecond drift) or partial claim fields.
• The failure typically surfaces on a different PR's merge commit, not the PR that introduced the contract change — the original PR's tests passed because they used the new contract correctly.

For each contract-tightening change in this run:

1. Identify the affected tool / class / method.
2. Grep all test files (and other call sites) for usages: grep -rn "<tool>\|<class>\|<method>".
3. Verify every usage is consistent with the new contract. Update any that are not.
4. Re-run the full :current:test suite (orchestrator-owned, not the agent) to confirm no fixture-vs-contract conflicts surfaced elsewhere.
5. Fixture repairs are orchestrator-owned and construction-only. When a fixture fails under the tightened contract, the orchestrator may adjust how the fixture is constructed (fix the stale call site) but must never adjust what it asserts. Anything that would touch an expectation instead of a construction call is not a fixture repair — re-dispatch the test author (this preserves the independence the trait exists to protect). Declare these commits in the review handoff: list each orchestrator fixture-repair commit's SHA alongside the impl-range/author-range pair (see Step 4's tracking table and Step 4b's disjointness check) so review-quality can tell a declared fixture repair apart from a silent implementer edit to src/test/**.
6. Doc-claims sweep after behavior-changing fixes: when an orchestrator-owned bug-fix changes shipped behavior after documentation was authored (e.g. a tokenizer or default flips mid-run), grep all changed docs for claims about the OLD behavior before finalizing (retro ac25db89: "case-insensitive" survived in 3 places after the fix made search case-sensitive).

This sweep is part of the orchestrator's verification step between waves, not the implementing agent's responsibility — agents are file-scoped and can't see the full fixture surface.

Model selection — always set model explicitly on every Agent dispatch:

Agent purpose	Model
Implementation (production code only)	model="sonnet"
Independent test authoring (Step 4b)	model="sonnet"
Architecture, complex multi-file synthesis	model="opus"
MCP bulk ops, materialization	model="haiku"

Omitting model causes the agent to inherit the orchestrator's model (typically opus), wasting tokens on sonnet-eligible implementation work.

After implementation agents return:

For Parallel-tier features, agents return having committed to feat/<feature-slug> inside the shared feature worktree. Record each agent's commit SHA range alongside the child's MCP item ID — needed for scoping the review agent later:

| Child UUID | Agent ID | Pre-SHA | Post-SHA | Test-Pre-SHA | Test-Post-SHA | Changed Files |
|------------|----------|---------|----------|--------------|---------------|---------------|
| <uuid>     | <id>     | <sha>   | <sha>    | <sha>        | <sha>         | <file list>   |

Capture pre-commit SHA before dispatch (git -C <feature-worktree> rev-parse HEAD) and post-commit SHA after the agent returns. The diff between them is exactly that child's work:

git -C <feature-worktree> diff <pre-sha>..<post-sha> --name-only

Test-Pre-SHA/Test-Post-SHA are captured the same way around the test author's dispatch (Step 4b) and stay blank until that wave runs.

Disjointness check (required whenever needs-test-author applies). After both ranges are captured, verify:

git -C <feature-worktree> diff <pre-sha>..<post-sha> --name-only          # impl range
git -C <feature-worktree> diff <test-pre-sha>..<test-post-sha> --name-only # author range

• impl-range ∩ src/test/** = ∅ (the implementer touched no test files)
• author-range ∩ src/main/** = ∅ and author-range is non-empty (the author touched only test files, and touched at least one)

A violation is reverted (git -C <feature-worktree> revert the offending commit, or a targeted git checkout of the crossed-boundary file back to the prior SHA) and recorded in implementation-notes — do not silently keep a cross-ownership commit.

---

Step 4b — Test Authoring

Applies only to items carrying the needs-test-author trait. Runs after implementation agents return (their commits exist on the branch/worktree) and before the orchestrator's build verification below (Direct tier inverts this ordering — see the Direct-tier bullet below) — the test author compiles against the real implemented surface, not a predicted one. Two distinct seats, do not conflate them: the planning seat already froze test-plan at queue phase, before this step, gating work entry (see Step 3's seat-timing rule); the test author seat here writes test CODE and fills test-manifest — it does not fill or re-open test-plan.

Per-tier sequencing:

• Direct tier: temporal-only degraded mode only (see Step 1) — no separate agent, and on a bug-fix the sequence is test-first-then-fix, not "tests after implementation": (a) fill test-plan at queue phase, before any implementation begins; (b) write the regression test from the diagnosis note's reproduction steps and observe it red against the pre-fix code, recording the red evidence (assertion, observed value) in test-manifest; (c) implement the fix; (d) confirm the test is green post-fix and record that confirmation too. test-manifest declares the single actor, and the disjointness check above does not apply (one actor, one range) — see Step 5's verdict rule for how this tier is scored.
• Delegated tier: one additional sequential dispatch on the same branch, after the implementation agent's commit lands. The test author owns its own gradle cycle on that branch (ktlintCheck → ktlintFormat → re-verify, same rule as Step 4's "Who runs the lint cycle") and runs :current:test itself before committing.
• Parallel tier: one test-author agent per child, dispatched as a dedicated wave between the implementation wave and the orchestrator's build verification (below). Authors in this tier do NOT run :current:test or :current:ktlintCheck — only ktlintFormat plus a compile self-check, mirroring the implementation dispatch template, since the orchestrator owns full build verification for the wave.

Blindness rule. The test author may read: the item's test-plan note, public signatures, domain models, existing test conventions/docs, and the implementer's changed-file names (not content). The test author must NOT read: the implementation diff content, the implementer's own tests, implementation-notes, or session-tracking. This is what makes the separation real rather than nominal — tests probe the spec, not the implementation's behavior.

Oracle-provenance obligation. Every scenario's expected result must trace to a source declared in test-plan (spec clause, stated algorithm, external reference) — never "what the code returns" and never the ticket's own worked example.

Manifest duty. Before returning, the test author fills test-manifest (work, required): actor id, test file paths, commit SHA range, S-id→test coverage mapping (covered / not-covered:reason), probes executed with results, forbidden-pattern declaration (every assumeTrue/escape with justification, or none), and any implementer-modification-to-test-files rationale (should be none if ownership held).

Skill routing. Invoke the test-author skill before filling test-manifest — it carries the scenario-derivation, oracle-derivation, blindness, and forbidden-pattern framework this step depends on. (The planning seat also invokes it earlier, at queue phase, for the scenario-derivation sections that inform test-plan — see Step 3.)

Arbitration — Red Author-Authored Tests

When a test the author wrote comes back red against the implementation, the test author does not decide who is at fault (test-author §8/§9) — it reports. The orchestrator arbitrates, with exactly three dispositions:

1. Implementation wrong. Re-dispatch the implementer, scoped to src/main/** only.
2. Test wrong. REQUIRES a spec citation before this disposition is available: the note key plus the quoted acceptance criterion plus the asserted-vs-observed values. "The implementation does X" is not evidence for this case — it is evidence for case 1. If no covering criterion exists to cite, this disposition is not available; fall through to case 3. Once cited, re-dispatch the test author, scoped to src/test/** only.
3. Spec wrong or silent. Escalate to the user. Amend task-scope/diagnosis first, then dispatch whichever side the amendment implicates.

Record every arbitration — case number, the citation (for case 2), and the resolving commit SHA — as a bullet in the child's implementation-notes. Never weaken, skip, or @Disable a test to unblock a wave, regardless of disposition; that is exactly the failure mode this trait exists to prevent (test-author §7, §9).

This carve-out also modifies the build-verification rule below: a red author-authored test is not a broken build. Route it to arbitration above; if unresolved, hold the child in work and report — do not dispatch a generic "fix agent" against it.

Test-author dispatch template (Delegated or Parallel):

Agent(
  prompt="""
  Working directory: <worktree-or-branch-path>
  Branch (already checked out): <branch-name>
  Scope (modify ONLY): src/test/** for this item's changed surface. Do NOT create or
  modify any file under src/main/**.

  You are the TEST AUTHOR for this item, independent of implementation. Read ONLY:
  the item's test-plan note, public signatures, domain models, existing test
  conventions, and the implementer's changed FILE NAMES (not diff content). Do NOT
  read: the implementation diff, the implementer's tests, implementation-notes, or
  session-tracking.

  Invoke the test-author skill before filling test-manifest — it defines scenario
  derivation, oracle derivation, blindness, and forbidden patterns. test-plan was
  already filled and frozen by the planning seat at queue phase; you do not fill it.

  Every scenario's expected result must trace to a stated oracle (spec clause,
  algorithm, external reference) — never "what the code returns."

  If a test you wrote fails: report it — never weaken the assertion, never add a
  skip; the orchestrator arbitrates.

  [Parallel tier only] Format + compile self-check (REQUIRED before returning):
    ./gradlew -p <worktree-path> :current:ktlintFormat :current:compileKotlin :current:compileTestKotlin
  Do NOT run :current:test or :current:ktlintCheck — orchestrator owns full build
  verification for this wave.
  [Delegated tier only] Run the full lint cycle yourself (ktlintCheck -> ktlintFormat
  -> re-verify) and :current:test before committing — you own gradle on this branch.

  Fill test-manifest (actor id, file paths, SHA range, S-id-to-test mapping, probes,
  forbidden-pattern declaration) before returning. Commit your changes with a
  descriptive message.
  """,
  model="sonnet",
  subagent_type="general-purpose"
)

Capture the test author's pre/post commit SHAs the same way as implementation agents (Test-Pre-SHA / Test-Post-SHA in the tracking table above), then run the disjointness check.

---

Step 4c — Build Verification and Wrap-Up

Build verification (orchestrator-owned, serialized). After each parallel-batch completes (or between sequential children), run from the feature worktree:

git -C <feature-worktree> status                            # confirm clean tree
./gradlew -p <feature-worktree> :current:test
./gradlew -p <feature-worktree> :current:ktlintCheck

A failure means a recently-committed child broke something. Dispatch a fix agent (same shared worktree) before continuing. Do not advance any child to review until the build is green — the trend memory has multiple sessions of flaky-test-hides-real-bug showing why retry-until-green is wrong.

Carve-out: a red author-authored test is not a build failure. On items carrying needs-test-author, a test failure traced to a test the test author wrote (Step 4b) is not "the build broke" — do not dispatch a generic fix agent against it. Route it to the Arbitration subsection in Step 4b instead. If arbitration doesn't resolve before this verification pass needs to conclude, hold the child in work phase and report the unresolved red test rather than forcing green through a fix-agent dispatch.

Why orchestrator owns gradle invocations: ./gradlew runs against a single Gradle daemon and a single build/ cache per project directory. Parallel gradlew test invocations against the shared feature worktree will queue at the daemon, corrupt the build cache, or hit Windows file locks. Serializing build verification at the orchestrator prevents this without slowing the agents (they're not running gradle).

For Delegated tier (single subagent), the agent commits to the working branch on the main directory. Capture the changed files via git diff main --name-only and proceed.

Post-implementation steps (run in the feature worktree for Parallel tier, or on the working branch for Direct/Delegated):

1. Run the /simplify skill on the changed code to check for reuse, quality, and efficiency — this is a cleanup pass before review, not a review itself
2. If /simplify made changes, the resulting test coverage work follows the ownership boundary above. On items carrying needs-test-author, re-dispatch the test author to write or update the covering tests (Step 4b) — the implementer/orchestrator does not touch src/test/** even for a simplify-driven update. On items without the trait, write or update tests inline as before. Either way, the simplify pass is still part of the work phase — all code changes require test coverage before advancing to review.
3. Log findings as work items — any issues surfaced by /simplify or during implementation that are not immediately addressed (pre-existing tech debt, optimization opportunities, related bugs) must be logged via /task-orchestrator:create-item before moving on. Do not discard findings.
4. Fill all work-phase notes following their guidancePointer — focus on context that downstream agents need to know
5. After implementation completes:
   • Subagent delegation: The agent returns after filling work-phase notes. The orchestrator then calls advance_item(trigger="start") to advance the item to the next phase.
   • Direct implementation: The orchestrator calls advance_item(trigger="start") itself after filling work-phase notes. In both cases, inspect newRole in the response to determine what comes next (see Step 5).

---

Step 5 — Review Phase

Before dispatching or performing review, check the item's current role. Inspect newRole from the advance_item response in the previous step:

• If newRole is terminal: The item's schema has no review phase (lightweight lifecycle). Review dispatch is not needed — the item completed through its natural lifecycle. Proceed to Step 6. Note: feature-task items skip review by default (work→terminal directly) — the needs-task-review trait re-enables a review phase for a specific child when needed.
• If newRole is review: Continue with review per tier below.

This step is tier-conditional:

Direct tier: Perform an inline review. Read the diff, verify correctness, confirm tests pass. If the review-phase note has a skillPointer (visible in the advance_item response or via get_context), invoke that skill for the evaluation framework before filling the review note. Write the review note, then advance to terminal: advance_item(trigger="start"). No separate review agent — the overhead exceeds the risk for 1-2 file changes with known fixes.

Delegated and Parallel tiers: Dispatch a separate review agent. The agent that implemented the code must not review its own work.

If the implementation used the shared feature worktree (Parallel tier), the review agent operates in that worktree, scoped to just this child's commits. The diff range is <pre-sha>..<post-sha> captured during dispatch (see Step 4).

Review agent template (copy verbatim, fill placeholders):

You are reviewing one child task within a shared feature worktree.

- Feature worktree: <FEATURE_WORKTREE_PATH>
- Feature branch: <FEATURE_BRANCH>
- This child's commit range: <PRE_SHA>..<POST_SHA>
- This child's changed files:
  <OUTPUT OF git -C <FEATURE_WORKTREE_PATH> diff <PRE_SHA>..<POST_SHA> --name-only>
- Other children may have committed before/after this one. Do NOT review their work
  — your scope is the diff range above only.

Run ALL commands from within the feature worktree.
Read ALL files from that directory. Do NOT read from the main working directory.

Tests have already been verified green by the orchestrator after the most recent
commit batch. Do NOT re-run gradle — focus on plan alignment, test quality, and
simplification per the review-quality skill.

Report every finding at every severity — do not self-filter to a high-severity-only
bar. Mark each finding blocking or observation and state your confidence; the
orchestrator's verdict handling is the downstream filter, not your own judgment.

If using Direct or Delegated tier (single working branch on the main directory), the review agent reads from the working branch and runs tests itself per the existing template — no worktree-specific scoping needed.

The review agent:

1. Reads the review-quality skill
2. Uses get_context(itemId=...) to load the item's notes and review-phase requirements
3. Reads the changed files (from the worktree path if isolated, or the working branch)
4. Runs the test suite AND the linter (both commands from Step 4's "Verification commands") — from the worktree if isolated. A PR with failing lint will not merge.
5. Evaluates plan alignment, test quality, and simplification
6. On items carrying needs-test-author, additionally:
   • Two-range ownership check: confirm the impl-range/author-range disjointness recorded during Step 4b actually holds by spot-checking git diff <impl-range> --name-only touches no src/test/** path and git diff <test-range> --name-only touches no src/main/** path. N/A-by-declaration on Direct-tier temporal-only items (Step 1, Step 4b): there is one actor and one range by design, so there is no second range to diff — record it as N/A: temporal-only, single actor rather than attempting the diff, and it cannot fail.
   • Temporal checks (Direct-tier temporal-only items only): confirm test-plan was filled and frozen at queue phase, before implementation began (Step 3's seat-timing rule), and — for a bug-fix — confirm the red-first evidence (the regression test observed failing against pre-fix code, per Step 4b/B3) is recorded in test-manifest.
   • Arbitration-record check: if any red author-test required arbitration (implementation wrong / test wrong / spec wrong), confirm the outcome is recorded in implementation-notes with the required detail (spec citation for a "test wrong" call: note key + quoted criterion + asserted-vs-observed).
   • assumeTrue/@Disabled scan on author-owned files: grep the test author's changed files for assumeTrue, @Disabled, or other weakening introduced after the author's first commit in this range. Any such introduction is an automatic blocking finding — independence does not permit softening a red test to unblock a wave. Verdict rule: test-independence-audit fails to not-independent (blocking) if any applicable check above fails, regardless of how green the test suite is — the ownership two-range check is not applicable, and cannot fail, on a Direct-tier temporal-only item. On a Direct-tier temporal-only item where every applicable check (temporal checks, arbitration-record, / scan) passes, the verdict is — never plain , matching §11.

Handling the verdict:

Verdict	Action
Pass	Proceed to Step 6
Pass with observations	Proceed to Step 6; log observations for follow-up
Fail — blocking issues	Stop and report to the user with the full findings. Do not attempt to fix autonomously — bring the human into the loop.

Review failures surface issues that may indicate systemic problems worth learning from. Automatically retrying hides these signals.

---

Step 6 — Finalize and PR

The shape of Step 6 depends on tier.

Direct and Delegated tiers — finalize per item

After review passes:

0. Post-dispatch commit audit (non-blocking): run git log --oneline -3 and git status --short and compare against what the orchestrator itself committed. Any commit a subagent made despite stop-boundary instructions is flagged for review here — inspect its scope before it rides into the squash-merge (a subagent commit lacks the co-author trailer; reconcile at merge time). On items carrying needs-test-author, additionally check each commit's file list for cross-ownership: an implementer commit touching src/test/**, or a test-author commit touching src/main/**, is flagged here even if it slipped past the Step 4b disjointness check — do not let it ride into the squash-merge unreconciled.

1. Verify the working branch is committed (orchestrator commits if Direct tier; subagent committed if Delegated). Stage only the files related to the implementation:

   git add <specific-files>
   git commit -m "$(cat <<'EOF'
   <type>(<scope>): <description>
   
   <body — what changed and why, referencing the MCP item>
   
   Co-Authored-By: Claude <[e-mail]>
   EOF
   )"
   

   Commit types: feat for features, fix for bugs, refactor for tech debt, perf for performance, test for test-only changes, chore for maintenance.

2. Push the working branch:

   git push -u origin <branch-name>
   

3. Create the PR:

   gh pr create --base main --title "<type>(<scope>): <description>" --body "$(cat <<'EOF'
   ## Summary
   <2-4 bullets>
   
   ## Test Results
   <test count, pass/fail, new tests>
   
   ## Review
   <verdict summary>
   
   ## MCP
   <item ID>
   EOF
   )"
   

4. After PR merges:

   git checkout main
   git pull origin main
   git branch -D <branch-name>
   

5. Advance the item to terminal:

   advance_item(transitions=[{ itemId: "<uuid>", trigger: "start" }])
   

6. After the item reaches terminal, follow the retrospective hook's directive if one fires (see retrospective.mode).

Report the PR URL and a summary.

Parallel tier — finalize ONCE at parent-feature completion

For Parallel-tier features with a shared feature worktree:

For each child task (after its review passes, if it has one):

1. For children whose schema/trait declares a review phase (e.g. needs-task-review), confirm review-checklist is filled. Children without one advance work→terminal directly — there is nothing to confirm.
2. advance_item(itemId=<child-uuid>, trigger="start") to move work→review→terminal (or work→terminal directly) as the child's schema dictates.
3. Do NOT push. Do NOT create a PR. The work is committed to feat/<feature-slug> inside the shared worktree; that's the integration point.

When all children reach terminal, the parent feature is ready to finalize:

1. Fill the parent's implementation-notes and session-tracking notes (aggregating across children — distributed-tracking pattern works as today).
2. Run final verification from the feature worktree:

   ./gradlew -p <feature-worktree-path> :current:test
   ./gradlew -p <feature-worktree-path> :current:ktlintCheck
   

3. Advance the parent to review and fill review-checklist (orchestrator-authored, summarizing across all children's reviews).
4. Push the feature branch:

   git -C <feature-worktree-path> push -u origin feat/<feature-slug>
   

5. Create one PR for the whole feature:

   gh pr create --base main --title "feat(<scope>): <feature description>" --body "$(cat <<'EOF'
   ## Summary
   <feature-level summary aggregating all children>
   
   ## Children completed
   - <child-1 title> (<MCP UUID>)
   - <child-2 title> (<MCP UUID>)
   ...
   
   ## Test Results
   <total test count, new tests added across feature>
   
   ## Review
   <feature-level review verdict, references each child's review-checklist>
   
   ## MCP
   Parent: <parent UUID>
   Children: <list of child UUIDs>
   EOF
   )"
   

6. After PR merges:

   git checkout main
   git pull origin main
   git worktree remove <feature-worktree-path>
   git branch -D feat/<feature-slug>
   

7. Advance the parent feature to terminal.
8. Retrospective — the plugin's retrospective hook fires on the parent's terminal transition. In dispatch mode (see retrospective.mode in .taskorchestrator/config.yaml) it directs a background /session-retrospective automatically — follow its directive; in nudge mode, or if no directive arrives, suggest running it manually.

Why one PR at parent finalization, not per child

• Coherent review context. The PR diff shows the whole feature, not N disjoint pieces.
• One CI cycle per feature instead of N. Local verification (orchestrator-owned gradle runs between commits) gives equivalent regression signal during development.
• No cross-PR contamination. Contract changes can't surface on a sibling's merge commit because there are no sibling PRs.
• No PR-body staleness. The PR body is authored once, after the feature is done, describing what actually shipped.
• Aggregate retrospective material. Distributed session-tracking notes across children plus parent-level aggregation gives clean retro input (validated by retro a7f6024f).

Local main always tracks origin/main — no divergence, no reset --hard needed.

---

Autonomous Batch Processing

When processing a Parallel-tier feature with multiple child tasks autonomously:

1. Step 2 — One worktree, one branch. Orchestrator creates the feature worktree and feature branch (feat/<slug>) at planning time. All children share it.
2. Step 4 — Dispatch into shared worktree. Agents dispatched without isolation: "worktree". Independent children dispatch in parallel waves; dependent children dispatch sequentially. Orchestrator scopes each agent's file list to prevent overlap.
3. Step 4b — Test-author wave. For children carrying needs-test-author, dispatch one test-author agent per child as its own wave, after that child's implementation wave and before build verification. Authors run ktlintFormat + compile self-check only (never :current:test/:current:ktlintCheck — the orchestrator owns those next). Capture Test-Pre-SHA/Test-Post-SHA per child and run the disjointness check before proceeding.
4. Build verification — orchestrator-owned, serialized. After each parallel wave (implementation or test-author), the orchestrator runs :current:test and :current:ktlintCheck from the feature worktree. Fix failures before advancing any child to review.
5. Step 5 — Review per child, scoped to that child's commit range, when the child has a review phase. feature-task children skip review by default (work→terminal directly) unless the needs-task-review trait is set, or needs-test-author is set (its test-independence-audit note adds a review phase). When a review phase applies, the review agent reads from the shared worktree but scopes its diff to <pre-sha>..<post-sha> for the child being reviewed, plus <test-pre-sha>..<test-post-sha> when a test-author wave ran for that child.
6. Step 6 — One PR at parent finalization. Children advance to terminal without pushing or PR'ing. Only when the parent feature itself reaches terminal does the orchestrator push feat/<slug> and open the single feature-level PR.
7. Track child commits — maintain a table mapping child UUID → pre-commit SHA → post-commit SHA → Test-Pre-SHA → Test-Post-SHA → status (implementing / test-authoring / reviewing / done / failed). Worktree path is shared across all children.
8. Report at the end — summarize children completed, review failures, and the single PR URL.

If any child hits a review failure, continue processing siblings (their commits are already in the feature branch). Report all failures together at the end. The orchestrator decides whether the failed child blocks parent finalization (e.g. fix-and-re-review), can be cancelled (descope from the feature), or warrants reverting its commits.

Bug-fix batches (multiple unrelated fixes) — these are NOT a Parallel-tier feature. Use Delegated tier per item, each with its own branch and PR (the legacy per-item flow). The shared-worktree pattern applies only when items share a parent feature item.

---

Worktree Strategy

For full setup, dispatch patterns, lifecycle, parallel validation, and test baseline management, see WORKTREE.md.

Quick reference:

Tier	Worktree	Branch	PR scope
Direct / Delegated (single item)	None — work on main directory	<type>/<slug>	One PR per item
Parallel (parent feature with N children)	One shared feature worktree	feat/<feature-slug> (one branch for all children)	One PR at parent finalization

Do NOT use isolation: "worktree" on the Agent tool for Parallel-tier child dispatches. That spawns a separate worktree per dispatch — the deprecated per-child PR pattern. For Parallel tier, the orchestrator pre-creates one shared worktree in Step 2 and dispatches each child agent into it.

When NOT to create any worktree:

• Direct/Delegated tier (single item — work on the main directory)
• Pure MCP operations with no file modifications
• Orchestrator implementing directly

---

Resuming In-Progress Work

Tier classification happens at Step 1 even when resuming. Classify the tier from the item's tags, file scope, and note state, then resume using that tier's pipeline.

If an item is already past the queue phase (e.g., previously planned but not implemented), the skill picks up from the current state:

Current role	Resume from
queue (notes filled)	Step 3 — advance and proceed
queue (notes missing)	Step 3 — fill missing notes
work (in progress)	Step 4 — check implementation state
work (notes filled)	Step 4 — advance to review
review	Step 5 — run review
terminal	Already done — report status

Always call get_context(itemId=...) first to determine exact state before resuming.