Plan Implement

Plan Implement

Use this workflow only after explicit selection as $plan-implement or a binding task instruction requiring it.

The job is to go faster by wasting less motion: fewer repeated code reads, fewer duplicate checks, fewer late review surprises, and less context loss after compaction.

This is a doctrine-only, prompt-first implementation skill. It must not become a deterministic harness, runner, controller, workflow engine, checklist executor, test scheduler, CI verifier, code review subprocess launcher, scorer, state machine, or script-backed completion judge.

Use When

• The user asks to implement an existing plan, plan phase, plan section, checklist, issue-body plan, or documented implementation scope.
• The user wants implementation to stay aligned with plan quality doctrine, plan-audit findings, review state, and proof freshness.
• The user wants progress to survive compaction without rereading the same plan and code surfaces repeatedly.
• The user wants native subagents or parallel-agent features used for independent read, review, or safe low-collision implementation slices when the current coding harness supports them.

Do Not Use When

• The plan does not exist yet. Use the repo's planning skill or normal planning flow.
• The user wants a plan audited before implementation. Use plan-audit.
• The user wants code already written for a plan reviewed without new implementation. Use plan-audit implementation-audit.
• The user wants a generic branch, diff, or PR reviewed. Use the host agent's normal review response.
• The user explicitly wants delegated external workers, resumable child sessions, or plan-wide worker orchestration with the parent acting as conductor and cynical reviewer. Route to conductor under the shared agent policy.
• The user wants one explicit external worker. Route to agent-delegate under the shared agent policy.

Non-Negotiables

• The plan remains the source of truth. Do not create a second plan in the worklog.
• The implementation log is a speed and resumability artifact. Keep it short enough for the next agent to read quickly.
• The plan audit log owns PLA-* and IMP-* review findings. Do not turn it into an implementation diary.
• Update artifacts at meaningful boundaries, not after every micro-edit.
• Choose depth-first slices: make one narrow approved plan truth real, review it while warm, verify impact, then advance through breadth already authorized by the plan. Depth-first sequencing is not permission to widen scope.
• Proof freshness matters. Reuse passing proof until a real invalidator makes it stale; run checks when the plan, changed code, impacted behavior, or a review finding gives a reason.
• Apply ../_shared/agent-orchestration-policy.md whenever implementation uses child agents.
• Use a coverage-led set of children for broad independent mapping, review, or safe low-collision implementation work when useful. Start each new independent child as a clean same-host native child when the active host supports it; keep lenses and owned paths non-overlapping and bound fanout by host slots, shared-file or shared-state collision risk, and parent integration capacity.
• Use bounded or full inherited context only for a named decision that exists solely in chat. Prefer plan, audit-log, implementation-log, and code paths over inheriting the parent's framing or completion story.
• Use the strongest read-only capability available for mapping and review children, also tell them not to edit or write, and have the parent compare repository status and diffs with the pre-dispatch state before accepting their evidence.
• Children may use native sub-agents within authorized scope and host limits; they may not start external agents.
• The parent owns child accounting, evidence spot-checking, deduplication, integration, finding scope disposition, source-of-truth updates, proof claims, and final completion claims.
• Resume the exact implementer child for an accepted repair in its owned scope. Every independent recheck uses a new clean critic rather than the implementer's or an earlier critic's context.
• Do not manually spawn separate coding-harness executables such as codex, claude, agent, grok, or kimi for ordinary acceleration. This lightweight lane may still hand an explicitly requested external worker or conductor to agent-delegate or conductor under the shared policy; external execution is a deliberate route, not a blanket ban.
• Do not claim a plan item complete from logs or checkboxes alone. Read code anchors and confirm the outcome is true.
• Apply ../_shared/scope-and-convergence.md. Before the first edit, recover the human baseline, initial minimal convergence closure, sign-off boundary, and explicit later human approvals. If a legacy plan cannot support a defensible boundary, stop for one human scope decision.
• A warm review, subagent, test, worklog, or plan edit cannot expand scope. Give every material finding a shared scope disposition. Only authorized and approved-convergence-required enter required implementation work; a newly discovered adjacent path is new-scope-needs-human, and already-built excess is subtraction work.

First Move

1. Read references/artifact-contract.md.
2. Read references/progressive-implementation-loop.md.
3. Read ../_shared/scope-and-convergence.md.
4. Read ../_shared/agent-orchestration-policy.md before creating or resuming any child.
5. Resolve the plan artifact, requested scope, stop boundary, repo root, audit log path, and implementation log path.
6. Read the plan, existing plan audit log if present, existing implementation log if present, local instructions, and current worktree state.
7. Identify the next narrow depth-first slice and the proof or review likely to matter.
8. If the scope is broad, decide whether native children can save real time for independent mapping or review slices.

Workflow

1. Resolve and restate the active plan scope. Do not silently widen.
2. Build the local truth cache: relevant plan anchors, code areas read, comparable patterns, side doors, proof already fresh, proof likely needed, and review lenses likely to matter.
3. Create or update <PLAN_STEM>_IMPLEMENTATION_LOG.md for non-trivial file-backed implementation scopes.
4. Implement the smallest useful depth-first slice using the repo's existing patterns and owner paths.
5. Review while the work is warm using plan-audit implementation-audit lenses. When children save time, use new clean native critics for independent read-only lenses. Send accepted repairs back to the exact implementer that owns the code, then use a different new clean critic for an independent recheck.
6. Run, assign, or reuse proof based on impact and freshness. Do not rerun checks only because prior context was forgotten.
7. Update the owning artifact: plan for source-truth changes, audit log for PLA-* or IMP-* findings, implementation log for resumability.
8. Advance to the next already-authorized slice only after the prior slice's code, plan, review, and proof state agree. New breadth requires human approval and re-approval.
9. At the requested stop boundary, perform a final lightweight plan-backed implementation check and report remaining gaps plainly.

Output Expectations

Return concise implementation status:

• active plan scope and stop boundary
• implementation log path and audit log path when applicable
• what changed
• what plan items moved state
• proof run, supplied, reused, stale, or intentionally not run
• review findings opened, repaired, rejected, or still open
• relevant code read and relevant code still unknown
• next useful move

For ongoing work, prefer a short progress update over a full report. The implementation log carries detail so the chat can stay readable.

Reference Map

• references/artifact-contract.md - plan, audit-log, and implementation-log ownership
• references/progressive-implementation-loop.md - ordered implementation loop
• references/proof-freshness.md - proof reuse, invalidators, and rerun triggers
• references/continuous-review.md - warm plan-backed review during implementation
• references/native-subagent-contract.md - native subagent use and prompt shapes
• ../_shared/agent-orchestration-policy.md - transport, starting context, continuation, isolation, topology, and parent-integration policy
• references/output-contract.md - progress and final report contracts
• references/examples.md - examples and anti-examples