Propose Implementation Plan Skill

Purpose

Create a TOML implementation plan that drives the implement-commit skill. The plan must be machine-parseable—the orchestrator reads it mechanically.

When to Use

• Feature design document exists and is approved
• Ready to begin implementation
• Need to coordinate work or track progress

Prerequisites

• Feature design exists in docs/features/NNNN-feature-name/design.md
• Test plan exists in docs/features/NNNN-feature-name/test-plan.md

Output Format

Create docs/features/NNNN-feature-name/implementation-plan.toml:

[meta]
feature = "feature-name"
feature_dir = "docs/features/NNNN-feature-name"
workspace = "./path/to/workspace"

[dependencies]
1 = []
2 = []
3 = [1, 2]

[[commits]]
id = 1
title = "Short description"
message = "feat(scope): conventional commit message"
files = ["path/to/file.rs"]  # Relative to workspace
acceptance = ["Criterion from CC table (CC-N)"]
anti_patterns = ["What NOT to do"]
tests = ["test_name_from_test_plan"]  # REQUIRED: maps to test-plan.md

Procedure

1. Study the Design Document

Read design.md thoroughly, noting:

• Module structure and affected files
• Dependencies between components
• Critical Constraints table (CC-1, CC-2, etc.)

2. Study the Test Plan (CRITICAL)

Read test-plan.md and create a mapping:

• List ALL test names from the Requirements Coverage table
• Each test MUST be assigned to exactly one commit
• Tests are the source of truth for acceptance criteria

3. Identify Capability Boundaries

Look for capability boundaries, not code artifact boundaries.

Good boundaries:

• A new module with its types, implementation, and tests together
• A user-visible capability (e.g., a new CLI command)
• A requirement being satisfied end-to-end

Anti-pattern: Splitting by artifact (types in one commit, impl in another, tests in a third).

4. Build the Dependency Graph

For each commit, list which commits must complete first. Encode as [dependencies] table where key is commit ID, value is list of dependency IDs.

The orchestrator uses this to determine parallel execution.

5. Map Tests to Commits

For each commit, list the specific test names from test-plan.md that verify it:

tests = [
  "test_protocol_encode_acquire_request",
  "test_protocol_decode_roundtrip",
]

Every test in test-plan.md must appear in exactly one commit's tests array.

This creates an auditable trace: test-plan.md → implementation-plan.toml → code.

6. Extract Critical Constraints

For each commit, copy relevant entries from the design's Critical Constraints table:

• acceptance = criteria that MUST be met (reference CC-N and test names)
• anti_patterns = what reviewers should reject

7. Write Commit Entries

For each commit:

[[commits]]
id = N                    # Sequential integer
title = "..."             # What this commit accomplishes
message = "..."           # Full conventional commit message
files = ["..."]           # Paths relative to workspace
acceptance = ["..."]      # From CC table + test descriptions
anti_patterns = ["..."]   # From CC table, or empty []
tests = ["..."]           # Test names from test-plan.md (REQUIRED)

8. Verify with Independent Agent

After drafting the plan, spawn a verification agent:

result = spawn(
    prompt=draft_spawn_prompt(SkillDefined(
        "Verify implementation plan covers all test-plan.md tests"
    )),
    context_files=[
        f"{skill_dir}/agents/verifier.md",
        f"{feature_dir}/test-plan.md",
        f"{feature_dir}/implementation-plan.toml",
    ],
    response_model=VerificationResult,
    read_only=True,
)

if not result.parsed.valid:
    # Fix gaps before proceeding
    agent_feedback(f"Plan incomplete: {result.parsed.gaps}")

The verifier checks:

• Every test in test-plan.md is assigned to a commit
• No test is assigned to multiple commits
• Acceptance criteria reference specific tests

9. Validate TOML

# Check TOML parses
python3 -c "import tomllib; tomllib.load(open('implementation-plan.toml', 'rb'))"

Commit Sizing Guidelines

Target: 200-400 lines changed per commit

Too Small:

• Types without implementation
• Traits without at least one impl
• Implementation without tests

Too Large:

• Multiple unrelated capabilities
• More than 500 lines
• Touches more than 5-6 files

Just Right:

• A module with types, impl, and tests (~200-400 lines)
• A CLI command with handler and tests (~150-350 lines)
• A complete adapter with tests (~200-400 lines)

Verification Model

from pydantic import BaseModel

class VerificationResult(BaseModel):
    valid: bool
    total_tests_in_plan: int
    tests_assigned: int
    gaps: list[str]  # Tests not assigned to any commit
    duplicates: list[str]  # Tests assigned to multiple commits

Example

See docs/features/0000-templates/implementation-plan.toml for a complete example.

Next Steps

After creating and verifying the plan:

1. Review for feasibility and sizing
2. Run implement-commit skill to execute