---
name: swarm-pi-implement
description: Implement an explicitly authorized change, fix, or refactor in an existing repository with Pi. Use for scoped file mutation; route new projects to scaffold, project tooling to setup, and design-only work to plan. Delivery, commit, and push remain separate decisions.
compatibility: Requires Node.js 22.19+, local shell command execution, and first-run npm registry access with a writable plugin directory; mutation workflows also require Git.
---

# Implement With Pi

Follow the [Skill Control Loop](../../references/skill-control-loop.md). Load
[Resource-Aware Execution](../../references/resource-aware-execution.md) before
expensive or recursive verification.

1. Confirm explicit mutation intent and an existing Git repository. Preserve
   user changes in place; route a new non-Git project to scaffold.
2. Add only missing scope, observable acceptance criteria, protected boundaries,
   and the smallest verification plan to the temporary prompt.
3. Run `$RUNNER implement --host "$HOST" --role executor --prompt-file "$PROMPT_FILE" --execution-mode supervised --approval-mode "$APPROVAL_MODE" --json`; with explicit user choice, append `--implementation-profile prewalk` to preserve exploration, TODOs, and the first edit through an in-session handoff.
4. Before implementation, honor the configured testing preference. If no
   invocation-level choice exists, ask the Host to offer 2–3 fitting methods
   (unit, integration, contract, regression, E2E, or property) plus no-new-tests.
   TDD is optional; no-new-tests still requires relevant existing checks.
5. Continue every non-terminal result through the control loop. Background is
   reserved for an explicitly requested, project-enabled `mechanical-executor`,
   with the assigned worktree left exclusively to Pi.
6. Inspect the actual diff, changed files, `runtimeSideEffects`, verification,
   and artifact. Exit code `5` presents `isolated-head` and
   `isolated-snapshot` without choosing. `workspace-unborn-head` routes to
   scaffold or approved adoption before resume.
7. A safe-dirty job-owned worktree is deliverable only after the verified,
   reversible artifact diff is shown and the user approves
   `$RUNNER jobs materialize --job <id> --json`.
8. Complete only when the actual diff satisfies the request, targeted Host-owned
   verification passes, and delivery state is explicit. `deliverable: false`
   artifacts remain isolated; commit, merge, and push remain Host-owned.

Host Assistance stays correlated and consume-once. Its evidence, assessment, or
recommendation cannot expand policy or intent.