| name | implement-plan |
| description | Orchestrates implementation of a multi-task plan by spawning plan-implementer subagents in parallel. Use when the user provides a plan file or plan text and asks to implement it, execute it, or says "implement plan", "run plan", "execute plan". |
Implement Plan
You are the orchestrator. Your job is to execute the attached plan by delegating tasks to plan-implementer subagents. Preserve your context window for coordination — never implement tasks yourself.
Workflow
1. Analyze the Plan
Read the plan the user attached. Identify:
- All discrete tasks/steps
- Dependencies between tasks (which must run sequentially vs. can run in parallel)
- Any ambiguous items that need clarification before starting
If anything is unclear, ask the user before proceeding.
2. Group Tasks for Parallelization
Partition tasks into parallel batches based on dependencies:
Batch 1 (parallel): [tasks with no dependencies]
Batch 2 (parallel): [tasks that depend on batch 1]
Batch 3 (parallel): [tasks that depend on batch 2]
...
Rules:
- Max 4 concurrent subagents, to bound machine load and coordination overhead
- Never parallelize browser-driving work. Queue browser checks behind the machine-wide
./scripts/pw-session.sh lock and run them sequentially after implementation work.
- Tasks touching the same file(s) go in the same subagent or sequential batches — never parallel
- Small related tasks can be grouped into one subagent to reduce overhead
- Large independent tasks get their own subagent
3. Execute Batches
For each batch, spawn plan-implementer subagents using the Task tool with subagent_type: "plan-implementer".
Each subagent prompt must include:
- Exact tasks to implement (copy from the plan, don't paraphrase loosely)
- File paths and context needed to work independently
- Constraints or edge cases from the plan
Use the plan-implementer agent's configured model unless the harness explicitly requires a supported model override for a straightforward task. Omit overrides for complex or cross-cutting tasks.
Wait for all subagents in a batch to complete before starting the next batch.
4. Handle Failures
When a subagent reports PARTIAL or FAILED:
- Read its report to understand what failed and why
- Decide: retry with more context, reassign to a different batch, or implement the fix yourself if trivial
- Don't retry blindly — adjust the prompt or approach
5. Verify
After all batches complete:
- Run
yarn build to confirm everything compiles
- Run
yarn lint and yarn type-check
- If the plan touched React components/hooks, run the repo-standard verification commands and add
yarn test when runtime behavior or tests changed
- For UI changes, verify with
./scripts/pw-session.sh across chrome, firefox, and webkit sequentially, reusing each engine session for the mobile viewport flow when relevant and closing it before opening the next
6. Report
Summarize to the user:
## Plan Execution Summary
### Completed
- Task 1 — files modified
- Task 2 — files modified
### Failed (if any)
- Task N — reason, what was tried
### Verification
- Build: PASS/FAIL
- Lint: PASS/FAIL
- Type-check: PASS/FAIL
Key Principles
- You orchestrate, subagents implement. Don't code changes yourself unless it's a trivial one-liner fix for a subagent failure.
- Context is precious. Every build log and file read you do in the main thread is context you can't get back. Delegate liberally.
- Parallelize non-browser work aggressively. Browser-driving work is always serialized by the machine-wide resource lock, even when tasks are otherwise independent.
- Verify at the end, not in between. Subagents run their own build checks. You do a final holistic verification.
