cc-plan-implementation

name	cc-plan-implementation
description	Implementation plan generation — decomposes an EP or task description into a parallelised, phase-based workplan with a Mermaid dependency graph, critical path analysis, per-task agent prompts, and a parallel dispatch table. Use when creating an implementation plan for an EP or any task description.
argument-hint	Provide the path to a completed EP file, or describe the task you want broken into an implementation plan.

Implementation Planning Instructions

These instructions tell the reading agent how to generate a structured Implementation Plan. The preferred input is a completed EP with Part-1 (proposal) and Part-2 (design details) already written. A plain task description is also accepted — see "Output for Standalone Task Descriptions" at the end of this file.

You MUST follow each step in sequence. NEVER skip a step or produce partial output.

---

Workflow

Step 1 — Ingest Input

If given an EP file path:

Read the full EP file. Extract and record:

• All components, services, APIs, and modules described in Part-2 (Design Details, Infrastructure, Data Migrations, Security & Testing sections)
• Acceptance Criteria from Part-1
• Constraints, risks, and dependencies stated anywhere in the EP

If the EP file path is not yet known, STOP and ask:

"Please provide the path to the EP file (or a task description) to generate the implementation plan."

If given a task description:

Identify core objectives, expected outcomes, technical scope, and dependencies on existing code or systems. Skip to Step 2.

Step 2 — Decompose into Implementation Tasks

Break the content into granular, self-contained tasks. Each task MUST:

• Produce one verifiable, reviewable change
• Reference specific files it creates or modifies
• Be completable without blocking other agents unless a true technical dependency exists

Assign each task:

Field	Value
ID	T01, T02, ... TNN (sequential)
Title	Short imperative phrase
Complexity	Low / Medium / High (see rating guide)
Depends On	Comma-separated IDs, or none
Files	List of files created or modified

Step 3 — Build Dependency Graph

Produce a Mermaid graph TD diagram from the task list. Each node MUST use the format ID["ID: Title"]. Add an arrow for every dependency. Mark critical-path edges with -->|critical| and style those nodes in red so the path is visually distinct. Group tasks into subgraph blocks by phase so parallel tasks are visually obvious.

graph TD
  subgraph "Phase 1 - parallel"
    T01["T01: Define Data Models"]
    T02["T02: Scaffold Project Structure"]
    T03["T03: Set Up CI Pipeline"]
  end

  subgraph "Phase 2 - parallel"
    T04["T04: Build Service Layer"]
    T05["T05: Build API Endpoints"]
  end

  subgraph "Phase 3"
    T06["T06: Wire Up and Integrate"]
  end

  subgraph "Phase 4 - parallel"
    T07["T07: Write Unit Tests"]
    T08["T08: Update Documentation"]
  end

  T01 -->|critical| T04
  T02 --> T04
  T02 --> T05
  T03 --> T05
  T04 -->|critical| T06
  T05 --> T06
  T06 -->|critical| T07
  T06 --> T08

  style T01 fill:#c0392b,color:#fff
  style T04 fill:#c0392b,color:#fff
  style T06 fill:#c0392b,color:#fff
  style T07 fill:#c0392b,color:#fff

Replace the example nodes and edges with the actual tasks. Do not include this example verbatim.

Step 4 — Compute Execution Phases

Group tasks into phases using these rules:

1. A task enters a phase only when ALL its dependencies have been completed in earlier phases.
2. CRITICAL — File-exclusivity: Tasks in the same phase MUST NOT modify the same existing file. Two tasks may CREATE different new files in the same phase. Only ONE task per phase may MODIFY any specific file.
3. Before finalising a phase, check every pair of tasks for file conflicts. If a conflict exists, move the lower-priority task to the next phase and document the reason.

Produce the phase table:

Phase	Tasks	Can Parallelise
1	T01	N/A — 1 task
2	T02, T03	Yes
3	T04	N/A — 1 task
4	T05, T06, T07	Yes

Step 5 — Identify Critical Path

The critical path is the longest chain of sequentially dependent tasks. State it explicitly:

Critical path:  T01 → T02 → T04 → T05
Sequential est: N tasks × avg time = X hours
Parallelised:   Y hours  (Z% reduction)

Label each critical-path task with [CRITICAL PATH] in its full task definition (Step 6).

Step 6 — Write Full Task Definitions

For every task, produce a definition using exactly this format. NEVER omit a field — use none or N/A if the field does not apply.

#### T01: [Task Title]  [CRITICAL PATH if applicable]

- [ ] [Task Title]
  - Phase: [N]
  - Complexity & Risk: [Low|Medium|High] — [one-line reason]
  - Depends On: [IDs or none]
  - Files:
    - Creates: [path or none]
    - Modifies: [path or none]
  - Description: [What to implement and why — 2-4 sentences.
    Reference the specific EP Part-2 section this satisfies,
    or the task description requirement it addresses.]
  - Acceptance Criteria:
    - [Specific, measurable check]
    - [Specific, measurable check]
  - Testing Requirements:
    - [Specific tests, or "none — trivial change"]
  - In Scope:
    - [Exactly what this task covers]
  - Out of Scope:
    - [What this task explicitly does not cover]

  **Agent Prompt:**
  Context: [EP title or task name] — Phase [N] of [M], Task [ID].
  Your task: [One-paragraph instruction a subagent can execute
  directly. Include: what to implement, which files to touch,
  which existing patterns to follow, and how to confirm
  completion.]
  Constraints: [Any file or scope exclusions.]
  Done when: [Acceptance criteria restated as a self-check list.]

Step 7 — Generate Parallel Dispatch Table

For each phase containing more than one task, produce a dispatch table showing which agent handles which task:

Phase	Agent	Task	Context to pass
2	Agent-A	T02	EP Part-2 sections A, B; T01
2	Agent-B	T03	EP Part-2 section C; T01 output

Context to pass MUST include:

• The relevant EP Part-2 section(s) or task requirement the task implements
• The IDs of completed prerequisite tasks and their key outputs (e.g., new file paths, schema names, interface definitions)

Step 8 — Assemble and Write Output

For EP files: write under a new ## Implementation Plan heading at the end of the EP file.

For standalone task descriptions: write to a new file at /docs/imp/NNNN-<slug>.md. Confirm the exact filename with the user BEFORE creating it.

DO NOT output the plan in chat — write to the file directly.

## Implementation Plan

### Technical Analysis

[For EPs: summarise or reference EP Part-2 findings. If Part-2
already contains a comprehensive analysis, write:
"See Part-2 Design Details and Infrastructure sections."
For task descriptions: provide a brief analysis of
architecture impact and affected components.]

### Dependency Graph

[Mermaid diagram from Step 3]

### Execution Phases

[Phase table from Step 4]

**Critical path:** [from Step 5]
**Sequential estimate:** X hours
**Parallelised estimate:** Y hours (Z% reduction)

### Implementation Tasks

[Full task definitions for T01 ... TNN from Step 6,
 ordered by phase then by task ID within each phase]

### Parallel Dispatch Plan

[Dispatch tables from Step 7 for each multi-task phase]

### Definition of Done

- [ ] All implementation tasks completed and checked off
- [ ] All tests passing (unit, integration, e2e as specified)
- [ ] Code review completed
- [ ] Documentation updated
- [ ] Feature verified in staging environment

After writing the file, confirm in chat:

"Implementation plan written to [file path]. [N] tasks across [M] phases. Critical path: [IDs]. Parallelised estimate: Y hours."

---

Complexity & Risk Rating Guide

Rating	When to use
Low	Straightforward change, well-understood pattern,
	minimal dependencies, no architectural impact
Medium	Moderate complexity, some unknowns, touches multiple
	components or requires cross-cutting changes
High	Complex logic, significant architectural change, many
	dependencies, or high security / data-integrity risk

---

Validation Checklist

Before confirming the plan is complete, verify all of the following. If any check fails, fix the issue before writing the file.

• Every task has a unique ID (T01...TNN)
• Every Depends On reference points to a real task ID
• No circular dependencies exist
• No two tasks in the same phase modify the same file
• Every task has a populated Agent Prompt section
• Critical path is identified and labelled
• All phase tasks have been checked for file conflicts
• Definition of Done checklist is present in the output