Picopala: Agents Checking Agents

Multi-agent orchestration where every agent's work is reviewed by a different agent in an iterative adversarial loop — the reviewer either APPROVES or sends back for REVISION, with fresh context each round.

Uses Claude Code Agent Teams — each teammate is a full independent Claude Code session with its own context window, communicating via messages and a shared task list.

Adversarial Cooperation Model

Based on dialectical autocoding research: a structured coach/player feedback loop where the reviewer (coach) independently validates against requirements, catching the implementer's (player's) blind spots and false confidence. Key principles:

•Fresh context each round — each reviewer spawn starts clean, avoiding context pollution
•Requirements contract — acceptance criteria are the single source of truth, not the worker's self-assessment
•Iterative convergence — multiple review rounds systematically close the delta between implementation and requirements
•Turn limits as complexity signal — if max rounds exhaust without approval, the task is likely too complex and should be decomposed

Custom Agents (bundled in this plugin)

Agent	Role	Tools	Model
`picopala:picopala-worker`	Implement task or apply review fixes, commit, report to lead, shut down	Read, Edit, Write, Bash, Glob, Grep, WebFetch, WebSearch, SendMessage, TaskGet (disallowed: TaskUpdate, TaskCreate, TaskList)	opus
`picopala:picopala-reviewer`	Cross-review with APPROVE/REVISE verdict, run verification commands	Read, Glob, Grep, Bash (whitelisted), SendMessage, TaskGet	opus

Workers can edit files and run any commands. Reviewers cannot edit (disallowedTools: Edit, Write) but can run whitelisted read-only verification commands (tests, typecheck, lint) via a PreToolUse Bash filter hook.

When NOT to Use

•Single-file edits or trivial changes — use a single session
•Sequential tasks where each step depends on the previous — use subagents
•Same-file edits by multiple agents — causes overwrites
•Quick bug fixes, typos, config changes — overhead isn't worth it

Example Triggers

code

/picopala Build a full authentication system with login, signup, password reset, and tests
/picopala Refactor the payment module — split into separate services with cross-review
/picopala Create a dashboard with API endpoints, React components, and E2E tests

Core Pattern

code

      ┌──────────────────────────────────────────────┐
      │         TECH LEAD (delegate mode only)        │
      │   Coordinates, delegates, synthesizes.        │
      │   NEVER implements, edits files, or builds.   │
      └───┬──────────────┬──────────────┬────────────┘
          │              │              │
   ┌──────▼──┐    ┌──────▼──┐    ┌──────▼──┐
   │Worker A │    │Worker B │    │Worker C │    IMPLEMENT
   │implement│    │implement│    │implement│
   │  commit │    │  commit │    │  commit │
   └────┬────┘    └────┬────┘    └────┬────┘
        ✕              ✕              ✕         SHUTDOWN workers
        │              │              │
   ┌────▼────┐    ┌────▼────┐    ┌────▼────┐
   │Review B │    │Review C │    │Review A │    CROSS-REVIEW (round 1)
   │→ REVISE │    │→APPROVE │    │→ REVISE │    findings → lead
   └────┬────┘    └─────────┘    └────┬────┘
        ✕                             ✕         SHUTDOWN reviewers
        │                             │
   ┌────▼────┐                   ┌────▼────┐
   │Fixer A  │                   │Fixer C  │    FIX (new agents)
   │  fixes  │                   │  fixes  │
   │  commit │                   │  commit │
   └────┬────┘                   └────┬────┘
        ✕                             ✕         SHUTDOWN fixers
        │                             │
   ┌────▼────┐                   ┌────▼────┐
   │Review B'│                   │Review A'│    CROSS-REVIEW (round 2)
   │→APPROVE │                   │→APPROVE │    fresh context, no pollution
   └─────────┘                   └─────────┘
        ✕                             ✕         SHUTDOWN reviewers

Pipeline

code

Intake → Plan → Create Team → [Execute Wave → Iterative Cross-Review Loop] → Cleanup

Phase 0: Intake (MANDATORY)

ALWAYS start here. Before any research or planning, use AskUserQuestion to understand:

•Scope: What exactly should be built? What's in/out of scope?
•Priorities: What matters most — speed, quality, specific features?
•Constraints: Tech stack, patterns to follow, things to avoid?
•Preferences: How many agents? Max review rounds? Model preferences?

Review round trade-offs (explain to user when asking):

•1 round: No second chance — any REVISE verdict = task failure. Good for well-specified simple tasks.
•2 rounds (default): One chance to fix review findings. Good balance of quality vs speed.
•3 rounds: Two fix attempts. For complex tasks where first pass might miss nuances.

Do NOT skip this phase. Do NOT assume scope, constraints, or priorities.

Phase 1: Plan

1.1 Research

•Investigate codebase: architecture, patterns, existing implementations, dependencies
•Fetch docs for external libraries/frameworks via web search

1.2 Create Dependency-Aware Plan

Each task declares explicit dependencies for maximum parallelization. Save to <topic>-plan.md using the template in references/plan-template.md.

Optional per-task fields for advanced control:

•model: Override model for worker/reviewer. For trivial tasks (single-component changes, adding one element, copy edits), set model: sonnet to reduce cost. Reserve opus for tasks involving state machine changes, cross-file refactoring, or complex logic.
•max_review_rounds: Override default max rounds for this specific task

1.3 Display Plan as ASCII Art

ALWAYS render the plan visually to the user using box-drawing characters showing waves and dependencies:

code

Wave 1 (parallel)              Wave 2 (parallel)              Wave 3
┌────────────┐ ┌────────────┐  ┌────────────┐ ┌────────────┐  ┌────────────┐
│ T1: Create │ │ T2: Install│  │ T3: Repo   │ │ T4: Service│  │ T5: API    │
│ DB Schema  │ │ Packages   │──│ Layer      │ │ Layer      │──│ Endpoints  │
│ [backend]  │ │ [config]   │  │ [backend]  │ │ [backend]  │  │ [backend]  │
└────────────┘ └────────────┘  └────────────┘ └────────────┘  └────────────┘
       │              │               ▲              ▲               ▲
       └──────────────┴───────────────┘              │               │
                                      └──────────────┴───────────────┘

Show this to the user and confirm before proceeding.

1.4 Validate Plan

bash

python ${CLAUDE_PLUGIN_ROOT}/skills/picopala/scripts/picopala.py validate <topic>-plan.md
python ${CLAUDE_PLUGIN_ROOT}/skills/picopala/scripts/picopala.py waves <topic>-plan.md

1.5 Plan Review

Spawn a Plan subagent to review for missing dependencies, ordering issues, gaps. Revise if needed.

Phase 2: Create Agent Team

2.1 Pre-Flight Check

MANDATORY before creating the team. Verify the working tree is clean:

bash

git diff --name-only HEAD

If the output is non-empty (tracked files have modifications), STOP and tell the user:

"The working tree has uncommitted tracked changes. Please commit or stash them before starting a picopala session. Uncommitted changes in the shared working tree will interfere with parallel workers."

Untracked files (?? in git status --porcelain) are acceptable — they don't cause merge conflicts between parallel workers. Only modified tracked files require commit/stash.

Do NOT proceed to team creation with modified tracked files.

2.2 Create Team

code

TeamCreate: team_name="picopala-<topic>", description="<task summary>"

2.3 Enter Delegate Mode

CRITICAL: The lead MUST operate in delegate mode. The lead NEVER:

•Reads code files
•Edits or writes files
•Runs builds or tests
•Implements anything

The lead ONLY:

•Spawns teammates (Task tool)
•Sends messages (SendMessage)
•Manages tasks (TaskCreate, TaskUpdate, TaskList)
•Synthesizes results and reports to user

Use Shift+Tab to enter delegate mode, or simply never use file/code tools.

2.4 Initialize State Directory

The lead creates the external state directory for hook approval markers:

bash

mkdir -p ~/.claude/picopala-state/picopala-<topic>

2.5 Create Shared Tasks

Use TaskCreate for each plan task. Set dependencies with TaskUpdate addBlockedBy. Assign to workers with owner.

Phase 3: Execute Wave

3.1 Spawn Workers

For each unblocked task, spawn a worker using the bundled picopala-worker agent:

code

Task tool:
  name: "worker-t1"
  team_name: "picopala-<topic>"
  subagent_type: "picopala:picopala-worker"
  prompt: |
    ## Context
    - Plan file: [path to <topic>-plan.md]
    - Overview: [relevant goals from plan]
    - Completed dependencies: [list]
    - Constraints: [risks from plan]

    ## Your Task
    **Task [ID]: [Name]**
    Location: [file paths]
    Description: [full description]
    Acceptance Criteria: [list from plan]
    Validation: [tests or verification steps]

i18n scoping (if the task touches translation files): Add to the prompt: "i18n scope: only add/modify keys in the [namespace] namespace of translation files (e.g., en.json, es.json). Do NOT touch keys in other namespaces."

Note on project-level quality hooks: If the project has stop hooks (e.g., typecheck, lint), they may fire on the lead's turn and report errors from workers' in-progress code. This is expected noise during parallel execution — ignore until all workers in the current wave have completed and been shut down.

3.2 Workers Implement, Commit, Report

Workers implement their task, commit, and message the lead with completion status. They then go idle.

3.3 Shutdown Workers

After receiving each worker's completion message, immediately send shutdown_request to the worker:

code

SendMessage type="shutdown_request" recipient="worker-t1" content="Implementation received. Shutting down."

Wait for shutdown_response (approve) before proceeding. All workers must be shut down before starting cross-review.

Phase 4: Iterative Cross-Review (Agents Checking Agents)

This is the core of the skill. The review loop iterates until APPROVED or max rounds reached. Each phase uses fresh agents — no agent is ever reused.

4.1 Spawn Reviewers (Round N)

For each completed task, spawn a reviewer using the bundled picopala-reviewer agent:

code

Task tool:
  name: "reviewer-t1-r1"
  team_name: "picopala-<topic>"
  subagent_type: "picopala:picopala-reviewer"
  prompt: |
    ## Task Under Review
    **Task [ID]: [Name]**
    - Plan file: [path to <topic>-plan.md]
    - Description: [task description from plan]
    - Acceptance Criteria: [from plan]
    - Files Modified: [from worker's output]
    - Review Round: [N] of [max_review_rounds]

    ## Output
    Send your findings as raw JSON (no code fences, no prose) via SendMessage to: [lead-name]
    Use summary: "T[ID] review: [your verdict]"

Launch ALL reviewers in parallel. The reviewer sends structured JSON findings directly to the lead.

4.2 Shutdown Reviewers

After receiving each reviewer's findings message, immediately send shutdown_request to the reviewer. Wait for shutdown_response before processing the verdict.

Parsing note: Extract the verdict field from the reviewer's JSON message. If the message is not valid JSON, treat it as REVISE and include the raw message in the fixer prompt for context.

4.3 Process Verdicts

If verdict = APPROVED:

•
The lead writes the approval marker via Bash (the only Bash the lead runs — required by the TaskCompleted hook). Important: sanitize the task_id to [a-zA-Z0-9_-] only (replace other chars with _) so the filename matches what the hook expects:
bash
```
mkdir -p ~/.claude/picopala-state/picopala-<topic> && \
echo "APPROVED by [reviewer-name] round [N] $(date -u +%Y-%m-%dT%H:%M:%SZ)" > ~/.claude/picopala-state/picopala-<topic>/[sanitized_task_id].approved
```
•Mark task complete. (The TaskCompleted hook verifies the marker exists.)

If verdict = REVISE and round < max_review_rounds:

•Spawn a new fixer agent with the findings embedded in its prompt:

code

Task tool:
  name: "fixer-t1-r1"
  team_name: "picopala-<topic>"
  subagent_type: "picopala:picopala-worker"
  prompt: |
    ## Context
    - Plan file: [path to <topic>-plan.md]
    - Overview: [relevant goals from plan]
    - Constraints: [risks from plan]

    ## Your Task
    **Task [ID]: [Name]**
    Acceptance Criteria: [list from plan]

    ## Review Findings (Round [N])
    [paste the full findings JSON from the reviewer]

    Fix all P0/P1 findings and any FAIL items in the requirements checklist.
    Use your judgment on P2/P3 findings.

•After receiving the fixer's completion message, immediately send shutdown_request to the fixer.
•Spawn a fresh reviewer (reviewer-t1-r2) — increment round in name.
•The fresh reviewer re-evaluates from scratch against acceptance criteria.
•This avoids context pollution — the new reviewer has no memory of previous rounds.

If verdict = REVISE and round >= max_review_rounds:

•Mark task as failed with note: "Exceeded review budget ([N] rounds). Consider decomposing into smaller tasks."
•Log the failure reason in the plan file. No fixer is spawned.

4.4 Lead Tracks Review Rounds

The lead maintains a mental model of each task's review state:

code

T1: round 1/2 → REVISE → fixer-t1-r1 → round 2/2 → APPROVED ✓
T2: round 1/2 → APPROVED ✓
T3: round 1/2 → REVISE → fixer-t3-r1 → round 2/2 → REVISE → FAILED (max rounds)

4.5 Lead Intervenes Only If Needed

The lead only steps in if:

•Deadlock or unexpected errors → lead escalates to user
•Task fails max rounds → lead reports to user with decomposition suggestion

Phase 5: Repeat

•Use TaskUpdate to mark completed/failed tasks
•Run python ${CLAUDE_PLUGIN_ROOT}/skills/picopala/scripts/picopala.py status <topic>-plan.md to check progress
•Check TaskList for newly unblocked tasks
•Spawn next wave of workers → iterative cross-review → repeat
•Continue until all tasks complete or fail

Phase 6: Cleanup

All agents should already be shut down at this point (each was shut down after finishing its work).

•
Safety net: If any agents are unexpectedly still active, send shutdown_request to each remaining teammate. Wait up to 10 seconds for shutdown_response. If a teammate does not respond:
- •Send ONE more shutdown_request with explicit content: "All work is done. Please shut down immediately."
- •
  Wait another 10 seconds. If still no response, proceed with force cleanup — remove team/task directories file-by-file (avoid rm -rf on home paths as security hooks may block it):
  bash
  rm ~/.claude/teams/picopala-<topic>/*.json 2>/dev/null; rmdir ~/.claude/teams/picopala-<topic> 2>/dev/null rm ~/.claude/tasks/picopala-<topic>/*.json 2>/dev/null; rmdir ~/.claude/tasks/picopala-<topic> 2>/dev/null
- •Do NOT loop indefinitely waiting for unresponsive agents.
•TeamDelete to remove team resources (if agents responded and team still exists)

•Remove state directory:

bash

rm ~/.claude/picopala-state/picopala-<topic>/*.approved 2>/dev/null
rmdir ~/.claude/picopala-state/picopala-<topic> 2>/dev/null

•You MUST render the execution summary before finishing. Use the template in references/summary-template.md. Show which tasks passed/failed, how many review rounds each took, and what files were changed.

Resources

•Plan template: references/plan-template.md — task structure with required fields
•Summary template: references/summary-template.md — execution report format
•Plan CLI: scripts/picopala.py — validate plans, compute waves, check status