implement-tasks

name	implement-tasks
description	Read a tasks.json file, resolve dependencies, and implement each task in the correct order using the task-pipeline CLI. Use when a tasks.json exists and needs execution. Do NOT use when there is no tasks.json (use implement instead).

Implement Tasks

Execute a tasks.json plan one task at a time, respecting dependencies.

When to Use

• A tasks.json exists
• The user says "implement the tasks" or "execute the plan"

When NOT to Use

• No tasks.json → Use prd-to-tasks first
• Single-file change → Use implement directly

Prerequisites

• task-pipeline CLI available at $HOME/.pi/agent/scripts/task-pipeline/
• tmux installed
• pi CLI available on PATH

Workflow

1. Validate the Task Graph

bun "$HOME/.pi/agent/scripts/task-pipeline/src/cli.ts" validate tasks.json --summary

This checks: valid JSON, missing dependencies, circular dependencies, phase keys, unique IDs. With --summary it also prints phase breakdown and critical path.

If validation fails, stop and report the issues. Do NOT proceed until fixed.

2. Determine Execution Order

Use topological sort to group tasks into parallel waves:

bun "$HOME/.pi/agent/scripts/task-pipeline/src/cli.ts" validate tasks.json --waves

Wave	Tasks	Deps
1	T001, T002	(none)
2	T003, T004	T001
3	T005	T002, T003

3. Generate Prompt Files

bun "$HOME/.pi/agent/scripts/task-pipeline/src/cli.ts" prompts tasks.json

This generates tasks/TASK-XXXX-prompt files — self-contained prompts that each subagent receives as input.

4. Spawn tmux Subagents (NEVER implement directly)

This skill is a pure orchestrator — it never writes code itself. Every task is delegated to an isolated tmux session running pi:

# Spawn next ready wave (auto-detects pending tasks)
bun "$HOME/.pi/agent/scripts/task-pipeline/src/cli.ts" spawn

# Spawn specific tasks
bun "$HOME/.pi/agent/scripts/task-pipeline/src/cli.ts" spawn T001 T003

# Preview what would spawn
bun "$HOME/.pi/agent/scripts/task-pipeline/src/cli.ts" spawn --dry-run

Async Wave-by-Wave Pattern

# 1. Spawn first wave (returns immediately)
bun "$HOME/.pi/agent/scripts/task-pipeline/src/cli.ts" spawn

# 2. Check status — poll until wave completes
bun "$HOME/.pi/agent/scripts/task-pipeline/src/cli.ts" status --compact

# 3. When current wave is done, spawn the next wave
bun "$HOME/.pi/agent/scripts/task-pipeline/src/cli.ts" spawn

# 4. Repeat steps 2-3 until all tasks are done

Monitoring

bun "$HOME/.pi/agent/scripts/task-pipeline/src/cli.ts" status           # full table
bun "$HOME/.pi/agent/scripts/task-pipeline/src/cli.ts" status --compact  # one-liner
bun "$HOME/.pi/agent/scripts/task-pipeline/src/cli.ts" status --pending  # pending only

# Peek at a specific task's live output
tmux capture-pane -t task-T005 -p | tail -20

5. Verify Completion

After each task, verify against acceptance criteria:

✅ T001: Set up project structure
  - ✓ Directory structure matches conventions
  - ✓ Type definitions compile

6. Handle Failures

If a task cannot be completed:

1. Diagnose — Is it a code bug, missing info, design flaw?
2. If fixable: Fix and re-verify
3. If blocked: Use grill-with-docs to ask the user
4. If dependency was wrong: Fix the dependency first, then retry

7. Report Progress

Phase 1: ✅ T001 setup, T002 config
Phase 2: 🔄 T003 in progress...

8. Final Report

When all tasks complete:

All [N] tasks complete. Acceptance criteria verified.

Key Rules

• Don't skip dependencies — implement in order
• Verify acceptance criteria — ensure each is met before moving on
• Report blockers — if a task can't proceed, explain why
• Never implement directly — always delegate to tmux subagents