arc-implementing

name	arc-implementing
description	Use when orchestrating large project implementation in a worktree

arc-implementing

Overview

Orchestrator for large projects. Automatically expands epic → features → tasks → execution.

Use when:

• project has specs/<spec-id>/dag.yaml
• in a worktree session (.arcforge-epic marker carries both epic and spec_id)
• specs/<spec-id>/epics/<epic-id>/epic.md or specs/<spec-id>/epics/<epic-id>/features/*.md present

Do not use when:

• small projects (use writing-tasks + agent-driven directly)
• tasks without a structured spec

Role

Implementer is the Orchestrator. It calls other skills and does not write code itself.

Trigger

• in a worktree session
• .arcforge-epic marker exists (supplies both epic and spec_id)
• or specs/<spec-id>/epics/<epic-id>/epic.md / specs/<spec-id>/epics/<epic-id>/features/*.md present

The Process

1. For each epic in the worktree, run the following phases in order.
2. Phase 0: Sync and check dependencies.
   • Run arc-coordinating to sync from base and check blocked_by.
   • If blocked_by is not empty: STOP and use the blocked format.
   • If ready: continue to Phase 1.
3. Phase 1: Epic → Features.
   • Call arc-writing-tasks
   • Input: specs/<spec-id>/epics/<epic-id>/epic.md
   • Output: features list (may already exist in specs/<spec-id>/epics/<epic-id>/features/*.md)
4. Phase 2: Per Feature.
   • 2a: Feature → Tasks.
     • Call arc-writing-tasks
     • Input: specs/<spec-id>/epics/<epic-id>/features/<feature>.md
     • Output: docs/tasks/<feature>-tasks.md
     • Quality gate: If tasks are vague or missing tests/commands, STOP and re-run arc-writing-tasks to refine. Max 2 refinement cycles — if still vague, escalate to human.
   • 2b: Execute Tasks.
     • Call arc-agent-driven
     • Input: tasks file
     • Output: completed code + commits
5. Phase 3: Feature complete.
   • Move to next feature, or finish the epic.

Skills Called

Phase	Skill	Input	Output
0	arc-coordinating	worktree	sync + blocked status
1	arc-writing-tasks	specs/<spec-id>/epics/<epic-id>/epic.md	features breakdown
2a	arc-writing-tasks	specs/<spec-id>/epics/<epic-id>/features/<feature>.md	tasks file
2b	arc-agent-driven	tasks file	completed code
2b	arc-dispatching-parallel	(via arc-agent-driven, if review finds multiple issues)	parallel fixes
End	arc-finishing	completed epic	merge decision

What Implementer Does NOT Do

• ❌ Write code directly (delegate to agent-driven)
• ❌ Split tasks manually (delegate to writing-tasks)
• ❌ Perform reviews (handled inside agent-driven)
• ❌ Run TDD cycle (handled inside agent-driven)

Completion Format

─────────────────────────────────────────────────
✅ Epic complete: <epic-name>

Features implemented:
- feature-1: 4 tasks, all passing
- feature-2: 6 tasks, all passing
- feature-3: 3 tasks, all passing

Total: 13 tasks, 0 failures
Commits: 13

Next: Use arc-finishing to decide merge/PR/keep/discard
─────────────────────────────────────────────────

Blocked Format

Dependencies Not Ready

─────────────────────────────────────────────────
⚠️ Implementer blocked: waiting for dependencies

Epic: <epic-name>
Blocked by: <dep-1>, <dep-2>

To resolve:
1. Complete blocking epics first
2. Run `arc-coordinating` sync from base
3. Verify `blocked_by` is empty

Then resume implementer
─────────────────────────────────────────────────

Task Failure

─────────────────────────────────────────────────
⚠️ Implementer blocked

Epic: <epic-name>
Feature: <feature-name>
Task: <task-id>
Issue: [description]

To resolve:
1. [action]

Then resume implementer
─────────────────────────────────────────────────

Integration

• Before: arc-coordinating (creates worktrees), arc-planning (creates DAG)
• Uses: arc-writing-tasks, arc-agent-driven, arc-dispatching-parallel
• After: arc-finishing (Step 0 selects the epic path)