Decomposing Plans for Parallel Execution

Decomposing Plans for Parallel Execution

Run immediately after /​write-plan to break monolithic plan into task files and identify parallelization opportunities.

Core principle: Individual task files save context + parallel batches save time = efficient execution

When to Use

Use after /​write-plan when you have a monolithic implementation plan and want to:

• Split it into individual task files (saves context tokens for subagents)
• Identify which tasks can run in parallel (up to 2 simultaneous subagents)
• Prepare for parallel-subagent-driven-development

Prerequisites

REQUIRED: Must have monolithic plan file at docs/​plans/​YYYY-MM-DD-<feature-name>.md

The Process

Step 1: Locate Plan File

User provides plan file path, or find most recent:

ls -t docs/​plans/​*.md | head -1

Step 2: Run Decomposition Script

Execute Python helper script:

python superpowers/​skills/​decomposing-plans/​decompose-plan.py <plan-file>

Script does:

1. Parses monolithic plan to extract tasks
2. Analyzes dependencies (file-based and task-based)
3. Identifies parallel batches (max 2 tasks at once)
4. Creates individual task files
5. Generates manifest.json
6. Reports statistics

Step 3: Review Generated Files

Check output directory docs/​plans/​tasks/<plan-name>/:

• Individual task files: <feature>-task-NN.md
• Execution manifest: <feature>-manifest.json

Example structure:

docs/​plans/
├── 2025-01-18-user-auth.md          # Monolithic plan
└── tasks/
    └── 2025-01-18-user-auth/         # Plan-specific subfolder
        ├── user-auth-task-01.md
        ├── user-auth-task-02.md
        ├── user-auth-task-03.md
        └── user-auth-manifest.json

Step 4: Verify Task Decomposition

Read a few task files to verify:

• Tasks are correctly extracted
• Dependencies are accurate
• Files to modify are identified
• Verification checklists are present

Step 5: Review Manifest

Read <feature>-manifest.json to verify:

• Parallel batches make sense
• No conflicting tasks in same batch
• Dependencies are correct

Step 6: Adjust if Needed

If decomposition needs adjustment:

• Manually edit task files
• Manually edit manifest.json parallel_batches array
• Update dependencies if needed

Step 7: Announce Results

Tell the user:

✅ Plan decomposed successfully!

Total tasks: N
Parallel batches: M
  - Pairs (2 parallel): X
  - Sequential: Y
Estimated speedup: Z%

Task files: docs/​plans/​tasks/<plan-name>/<feature>-task-*.md
Manifest: docs/​plans/​tasks/<plan-name>/<feature>-manifest.json

Next: Use parallel-subagent-driven-development skill

Task File Format

Each task file created:

# Task NN: [Task Name]

## Dependencies
- Previous tasks: [list or "none"]
- Must complete before: [list or "none"]

## Parallelizable
- Can run in parallel with: [task numbers or "none"]

## Implementation

[Exact steps from monolithic plan for THIS task only]

## Files to Modify
- path/​to/​file1.ts
- path/​to/​file2.ts

## Verification Checklist
- [ ] Implementation complete
- [ ] Tests written (TDD - test first!)
- [ ] All tests pass
- [ ] Lint/​type check clean
- [ ] Code review requested
- [ ] Code review passed

Manifest Format

{
  "plan": "docs/​plans/​2025-01-18-feature.md",
  "feature": "feature-name",
  "created": "2025-01-18T10:00:00Z",
  "total_tasks": 5,
  "tasks": [
    {
      "id": 1,
      "title": "Implement user model",
      "file": "docs/​plans/​tasks/​feature-task-01.md",
      "dependencies": [],
      "blocks": [3],
      "files": ["src/​models/​user.ts"],
      "status": "pending"
    },
    {
      "id": 2,
      "title": "Implement logger",
      "file": "docs/​plans/​tasks/​feature-task-02.md",
      "dependencies": [],
      "blocks": [],
      "files": ["src/​utils/​logger.ts"],
      "status": "pending"
    },
    {
      "id": 3,
      "title": "Add user validation",
      "file": "docs/​plans/​tasks/​feature-task-03.md",
      "dependencies": [1],
      "blocks": [],
      "files": ["src/​models/​user.ts"],
      "status": "pending"
    }
  ],
  "parallel_batches": [
    [1, 2],  // Tasks 1 and 2 can run together
    [3]      // Task 3 must wait for task 1
  ]
}

Dependency Analysis

Script analyzes three types of dependencies:

1. Explicit Task Dependencies

If task content mentions "after task N" or "depends on task N":

Task 3: "After task 1 completes, add validation..."
→ Task 3 depends on Task 1

2. File-Based Dependencies

If tasks modify the same file:

Task 1: Modifies src/​models/​user.ts
Task 3: Modifies src/​models/​user.ts
→ Task 3 depends on Task 1 (sequential)

3. Default Sequential

Unless marked "independent" or "parallel", tasks depend on previous task:

Task 1: ...
Task 2: (no explicit dependency mentioned)
→ Task 2 depends on Task 1

Parallel Batch Identification

Algorithm:

1. Find tasks with no unsatisfied dependencies
2. Group up to 2 tasks that:
   • Have no mutual dependencies
   • Don't modify same files
   • Don't block each other
3. Create batch
4. Repeat until all tasks scheduled

Max 2 tasks per batch (constraint for code review quality)

Benefits

Context Savings

• Before: Each subagent reads ~5000 tokens (monolithic plan)
• After: Each subagent reads ~500 tokens (task file)
• 90% context reduction per subagent

Time Savings

• Before: 5 tasks × 10 min = 50 min
• After: 3 batches × 10 min = 30 min (if 2 parallel pairs)
• 40% time reduction for parallelizable plans

Clarity

• Each subagent has focused, bounded scope
• Clear verification checklist per task
• No confusion about which task to implement

Red Flags

Never:

• Skip running the decomposition script (manual decomposition error-prone)
• Proceed with decomposed plan without reviewing manifest
• Ignore dependency conflicts flagged by script
• Skip verifying parallel batches make sense

If script fails:

• Check plan file format (needs clear task sections)
• Verify plan has recognizable task markers ("## Task N:", etc.)
• Manually create task files if plan format is unusual
• Report issue for script improvement

Integration

Required prerequisite:

• writing-plans - REQUIRED: Creates monolithic plan that this skill decomposes

This skill enables:

• parallel-subagent-driven-development - REQUIRED NEXT: Executes the decomposed plan with parallel subagents

Alternative workflow:

• subagent-driven-development - Use if you DON'T want parallel execution (works with monolithic plan)

Example Output

$ python superpowers/​skills/​decomposing-plans/​decompose-plan.py docs/​plans/​2025-01-18-user-auth.md

📖 Reading plan: docs/​plans/​2025-01-18-user-auth.md
✓ Found 5 tasks

🔍 Analyzing dependencies...
  Task 1: No dependencies
  Task 2: No dependencies
  Task 3: Depends on task 1 (file conflict: src/​models/​user.ts)
  Task 4: Depends on task 3
  Task 5: No dependencies

⚡ Identifying parallelization opportunities...
  Batch 1: Tasks 1, 2 (parallel)
  Batch 2: Tasks 3, 5 (parallel)
  Batch 3: Task 4 (sequential)

📝 Writing 5 task files to docs/​plans/​tasks/​2025-01-18-user-auth/
  ✓ user-auth-task-01.md
  ✓ user-auth-task-02.md
  ✓ user-auth-task-03.md
  ✓ user-auth-task-04.md
  ✓ user-auth-task-05.md

📋 Writing execution manifest...
  ✓ user-auth-manifest.json

============================================================
✅ Plan decomposition complete!
============================================================
Total tasks: 5
Parallel batches: 3
  - Pairs (2 parallel): 2
  - Sequential: 1
Estimated speedup: 40.0%

Manifest: docs/​plans/​tasks/​2025-01-18-user-auth/​user-auth-manifest.json

Next: Use parallel-subagent-driven-development skill

Troubleshooting

Script Can't Parse Tasks

Problem: Script reports "Found 0 tasks"

Solutions:

1. Check plan format - needs clear task markers:
   • ## Task 1: Title
   • ## 1. Title
   • **Task 1:** Title
2. Manually add task markers if plan uses different format
3. Run script with --verbose for debug output

Incorrect Dependencies

Problem: Script identifies wrong dependencies

Solutions:

1. Review manifest.json parallel_batches
2. Manually edit manifest to fix dependencies
3. Add explicit dependency markers in plan ("depends on task N")

Too Conservative (Too Many Sequential)

Problem: Script creates too many sequential batches

Solutions:

1. Mark tasks as "independent" in plan text
2. Manually edit manifest parallel_batches to add parallelization
3. Verify file paths are correctly extracted

Next Steps

After decomposition:

1. Review task files for accuracy
2. Review manifest for correct dependencies
3. Announce results to user
4. Proceed to parallel-subagent-driven-development skill

After Decomposition

After decomposition completes successfully, prompt user:

Plan decomposed into X tasks across Y parallel batches.

Manifest: `docs/​plans/​tasks/​YYYY-MM-DD-<feature>/​manifest.json`
Tasks: `docs/​plans/​tasks/​YYYY-MM-DD-<feature>/<task-files>`

Options:
A) Review the plan with plan-review
B) Execute immediately with parallel-subagent-driven-development
C) Save and exit (resume later with /​cc:resume)

Choose: (A/​B/​C)

If user chooses A:

• Invoke plan-review skill
• After review completes and plan approved
• Return to this prompt (offer B or C)

If user chooses B:

• Proceed directly to parallel-subagent-driven-development skill
• Begin executing tasks in parallel batches

If user chooses C:

• Invoke state-persistence skill to save execution checkpoint
• Save as YYYY-MM-DD-<feature>-execution.md with:
  • Plan reference and manifest location
  • Status: ready to execute, 0 tasks complete
  • Next step: Resume with /​cc:resume and execute
• Exit workflow after save completes