Context Engineering: Plan Phase (Enhanced)

When invoked, create a detailed implementation plan with chunk-based todolists:

Key Innovation: Inter-Phase Awareness

This plan phase KNOWS:

• •RPI-Research structured chunks specifically for sequential processing
• •RPI-Implement will read each CHUNK-Pn as an atomic implementation unit
• •Each CHUNK-Pn todolist must be independently executable
• •Chunk dependencies must be explicit for proper execution ordering

Prerequisites

• •Research document exists at .claude/research/active/[feature]_research.md
• •Research document contains chunk manifest
• •If not found, run /context-eng:research $ARGUMENTS first

Chunk Processing Loop

FOR each CHUNK-Rn in research_chunks:
  1. Read CHUNK-Rn content
  2. Create CHUNK-Pn todolist:
     - Define atomic action items
     - Specify file:line for each action
     - Assign test for each action
     - Document chunk-specific rollback
  3. Mark CHUNK-Rn status as PLANNED
  4. Define CHUNK-Pn dependencies
  5. Proceed to next CHUNK-R(n+1)
END LOOP

Process

1. •

   Load Research Document

   • •Read the research document for $ARGUMENTS
   • •Extract chunk manifest
   • •Extract per-chunk files and line numbers
2. •

   For Each Research Chunk (CHUNK-Rn):

   a. Analyze chunk content:

   • •Files explored with line numbers
   • •Code flow analysis
   • •Dependencies identified

   b. Create CHUNK-Pn todolist:

   markdown

   | # | Action | File | Lines | Risk | Test | Status |
   |---|--------|------|-------|------|------|--------|
   | 1 | [Action] | file.ext | XXX | LOW | test_x | ⏳ |
   

   c. Define per-todo details:

   • •Current code snippet
   • •Proposed change
   • •Test to run after

   d. Mark research chunk as PLANNED

   e. Document chunk dependencies

3. •

   Create Chunk Dependency Graph

   code

   CHUNK-P1 → CHUNK-P2 → CHUNK-P3
              ↓
   CHUNK-P4  CHUNK-P5
   

4. •

   Generate Inter-Phase Contract

   code

   EXPECTED_CONSUMER: rpi-implement
   CHUNK_PROCESSING_ORDER: dependency-ordered
   MARK_AS_IMPLEMENTED_WHEN: all chunk todos complete
   UPDATE_RESEARCH_STATUS: true
   

5. •

   Create Plan Document

   • •Save to .claude/plans/active/[feature]_plan.md
   • •Include chunk manifest
   • •Include per-chunk todolists
   • •Include verification checklist

Plan Format (Chunk-Based)

# Implementation Plan: [Feature]

## Chunk Manifest
| Chunk ID | From Research | Status | Todos | Dependencies | Ready |
|----------|---------------|--------|-------|--------------|-------|
| CHUNK-P1 | CHUNK-R1 | READY | 4 | None | ✅ |
| CHUNK-P2 | CHUNK-R2 | READY | 5 | CHUNK-P1 | ⏳ |

## CHUNK-P1: [Domain] (from CHUNK-R1)

**Status:** READY
**Dependencies:** None
**Update Research When Complete:** Mark CHUNK-R1 as IMPLEMENTED

### Todolist
| # | Action | File | Lines | Risk | Test | Status |
|---|--------|------|-------|------|------|--------|
| 1 | [Action] | file.ext | XXX | LOW | test_x | ⏳ |

### Todo 1: [Action Name]
**File:** path/to/file.ext
**Lines:** X-Y
**Current:** [code block]
**Proposed:** [code block]
**Test:** [command]

### Chunk Completion Criteria
- [ ] All todos complete
- [ ] Update CHUNK-R1 status
- [ ] Proceed to dependent chunks

## Inter-Phase Contract
[contract for rpi-implement]

## Rollback (Per Chunk)
- CHUNK-P1: git revert [hash]

Context Budget

• •Research doc: 20k tokens
• •Plan creation: 15k tokens
• •Total: 35k tokens (17.5%)

Next Step

After approval, run /context-eng:implement $ARGUMENTS

RPI-Implement will:

1. •Load chunk manifest
2. •Process chunks in dependency order
3. •Execute todos atomically per chunk
4. •Mark chunks as IMPLEMENTED
5. •Update research document status