Orchestration

Multi-Agent Orchestration Skill

✨ SKILL ACTIVATED: orchestration
   Purpose: Design conductor/subagent orchestrated systems
   Functionality: Orchestration patterns, conductor design, subagent archetypes, TDD lifecycle, quality gates
   Output: Orchestrated system architecture with conductor, subagents, and plan files
   Scope: Portable across VS Code, CLI, Claude, Cursor, and compatible agents

Purpose

Comprehensive methodology for designing and generating orchestrated multi-agent systems where a conductor agent coordinates multiple subagents through structured phases with quality gates, TDD enforcement, and plan file tracking. Goes beyond simple handoff chains to provide full project lifecycle orchestration.

When to Use This Skill

• Repository has 50+ files or multiple specialized domains
• TDD lifecycle enforcement is required across implementation phases
• Multiple specialized roles need coordinated execution (planning, implementation, review, research)
• Parallel execution of independent tasks would improve throughput
• Context conservation is critical (large codebases where agents need focused scope)
• Quality gates are needed between phases (planning approval, code review, commit gate)

Orchestration Patterns

Pattern Decision Matrix

Orchestra Pattern (3-5 agents)

Standard orchestration for structured project work. One conductor coordinates subagents through sequential phases.

Conductor (orchestrates all phases)
  ├─→ Planner (requirements → implementation plan)
  ├─→ Implementer (code changes following plan)
  └─→ Reviewer (validation and quality checks)

Atlas Pattern (5-10 agents)

Advanced orchestration for large codebases with parallel execution and context conservation.

Conductor (orchestrates + manages parallel execution)
  ├─→ Planner (architecture and phase design)
  ├─→ Researcher (codebase analysis, dependency mapping)
  ├─→ Scout (file discovery, pattern identification)
  ├─→ Implementer-A (frontend changes)  ←── parallel
  ├─→ Implementer-B (backend changes)   ←── parallel
  ├─→ Implementer-C (database changes)  ←── parallel
  ├─→ Reviewer (code quality, security)
  └─→ Domain Specialist (API design, testing, etc.)

Custom Pattern

User-defined agent composition tailored to specific project needs.

Conductor Design

The conductor is the central orchestration agent that manages the entire workflow lifecycle.

Conductor Requirements

1. agent tool + handoffs array — Must be able to invoke any subagent in the system via agent tool and define all subagent transitions in the handoffs YAML field
2. Optional agents field — Can explicitly list allowed subagents for security and workflow control
3. State Tracking — Maintains current phase, completed phases, and blocking issues
4. Quality Gates — Enforces approval checkpoints (minimum 3 pause points)
5. No Direct Implementation — Conductor never writes code or modifies files directly
6. Plan File Management — Creates and updates plans/PLAN.md for progress tracking
7. Model Tier — Uses highest-capability model (e.g., Claude Sonnet 4.5, GPT-4)

Conductor YAML Structure

---
description: 'Orchestrates {SystemName} workflow: coordinates subagents through phases with quality gates and TDD enforcement'
model: Claude Sonnet 4.5 (copilot)
tools: ['search', 'search/codebase', 'agent']
user-invokable: true
agents: ['Planner', 'Implementer', 'Reviewer']  # Optional: explicit subagent list
handoffs:
  - label: '{Phase 1 action}'
    agent: '{Subagent1Name}'
    prompt: '{Context for subagent}'
    send: false
  - label: '{Phase 2 action}'
    agent: '{Subagent2Name}'
    prompt: '{Context for subagent}'
    send: false
---

Mandatory Pause Points

Every conductor must include at least 3 pause points:

1. After Planning Phase — User approves implementation plan before any code changes
2. After Implementation Phase — User reviews changes before commit
3. After Review Phase — User confirms final quality before closing

State Tracking Template

## Current State
- **Phase**: {current phase name}
- **Status**: IN_PROGRESS | BLOCKED | AWAITING_APPROVAL
- **Completed**: [list of completed phases]
- **Blocking Issues**: [any blockers]
- **Next**: {next phase or action}

Subagent Archetypes

Subagent Requirements

1. Input/Output Contract — Clear description of what the subagent receives and produces
2. Scope Boundaries — Explicit limits on what the subagent can and cannot modify
3. Model Tier — Appropriate model for the complexity of the role
4. Tool Selection — Minimum necessary tools for the role (see asset-design skill)
5. Role Description — Specific, focused expertise description

Subagent YAML Structure

---
description: '{Role}: {specific capability description}'
model: {appropriate model tier}
tools: ['{tool1}', '{tool2}']
---

TDD Lifecycle Enforcement

Every implementation phase follows the TDD lifecycle:

Plan → Test → Implement → Review → Commit

Per-Phase TDD Template

### Phase {N}: {Phase Name}

**Plan**: Define requirements and acceptance criteria
  - [ ] Requirements documented in PLAN.md
  - [ ] Acceptance criteria specified

**Test**: Write failing tests that define expected behavior
  - [ ] Test files created
  - [ ] Tests fail as expected (red phase)

**Implement**: Write code to make tests pass
  - [ ] Implementation follows plan specifications
  - [ ] All tests pass (green phase)

**Review**: Validate quality and correctness
  - [ ] Code review completed
  - [ ] No regressions introduced
  - [ ] Security review passed

**Commit**: Stage and commit changes
  - [ ] Changes staged
  - [ ] Commit message follows conventions
  - [ ] PLAN.md updated with completion status

TDD Enforcement Levels

• strict (default): All phases require Plan → Test → Implement → Review → Commit
• relaxed: Plan → Implement → Review → Commit (tests optional per phase)
• none: No TDD enforcement (phases proceed without test gates)

Plan File Architecture

Directory Structure

plans/
├── PLAN.md                    # Main orchestration plan
├── phase-1-complete.md        # Phase completion records
├── phase-2-complete.md
└── FINAL-REPORT.md            # Generated after all phases complete

PLAN.md Structure

See OrchestrationPlan.template.md for the full template.

Key sections:

1. Summary — Project goal and system configuration
2. Phase Definitions — Ordered list of phases with agents, inputs, outputs
3. Quality Gates — Gate definitions with approval criteria
4. TDD Lifecycle — Per-phase TDD requirements
5. State Tracking — Current phase, completed phases, blockers
6. Progress Log — Timestamped entries of phase transitions

Phase Completion Record

# Phase {N} Complete: {Phase Name}

**Status**: COMPLETED
**Agent**: {agent that executed}
**Duration**: {time}
**Artifacts**: {files created/modified}
**Quality Gate**: {APPROVED | N/A}
**TDD Results**: {test count, pass/fail}
**Notes**: {any relevant observations}

Quality Gates Framework

Gate Types

Quality Gate Schema

## Quality Gate: {Gate Name}

**Phase**: {phase number and name}
**Agent**: {reviewing agent}
**Criteria**:
- [ ] {criterion 1}
- [ ] {criterion 2}
- [ ] {criterion 3}

**Result**: APPROVED | NEEDS_REVISION | FAILED
**Notes**: {reviewer comments}
**Action**: {next step based on result}

Parallel Execution (v1.109)

Automatic Parallel Execution

VS Code 1.109+: Independent subagents automatically run in parallel when invoked by the conductor. No manual configuration needed — the system detects independence and executes concurrently.

When to Use Parallel Execution

• Independent code areas (frontend/backend/database)
• Multiple test suites that don't share state
• Documentation generation alongside implementation
• Research tasks that don't modify files

Parallel Execution Rules

1. Maximum 10 concurrent subagents — Prevents resource contention
2. No shared file modifications — Parallel agents must work on disjoint file sets
3. Conductor synchronization — Conductor waits for all parallel agents before next phase
4. Failure isolation — One agent's failure doesn't block others (conductor handles retry)

Context Conservation Strategy

For large codebases, limit each subagent's context to relevant files:

### Subagent Context Scope
- **Files**: {glob pattern of relevant files}
- **Max Files**: 20 (prefer focused context)
- **Dependencies**: {list of files the agent may read but not modify}
- **Exclusions**: {files explicitly out of scope}

VS Code Configuration

Required Settings

{
  "chat.customAgentInSubagent.enabled": true
}

VS Code 1.109+ enables the agent tool for subagent invocation. Independent subagents run in parallel automatically, improving throughput for multi-agent workflows.

New Frontmatter Controls (v1.109):

• user-invokable: false — Hide subagents from picker (orchestration-only)
• disable-model-invocation: true — Prevent auto-invocation by other agents
• agents: ['AgentA', 'AgentB'] — Limit which subagents can be invoked (requires agent tool)

Model Assignments

Configure per-agent model assignments in VS Code settings or agent YAML model field to match the recommended model tier for each archetype.

Integration with Other Skills

Pairs Well With:

• asset-design — Decision framework for when to use orchestration vs standalone
• repo-analysis — Understand repository complexity before choosing pattern
• planning — Strategic planning within orchestrated phases
• documentation — Documentation generation within orchestrated workflows

Success Criteria

A well-designed orchestrated system provides:

• ✅ Clear conductor with state tracking and quality gates
• ✅ Focused subagents with defined input/output contracts
• ✅ TDD lifecycle enforcement at configurable strictness
• ✅ Plan file tracking with phase completion records
• ✅ Quality gates at critical decision points (minimum 3)
• ✅ Appropriate model tiers matched to agent roles
• ✅ Parallel execution support when applicable (Atlas pattern)
• ✅ Context conservation for large codebases

Skill Type: Architecture and Orchestration Complexity: High Prerequisites: Understanding of VS Code Copilot agent files, handoff patterns, and multi-agent workflows

Cross-Platform: Orchestration methodology works across all platforms; agent file generation requires VS Code for execution.

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