executing-an-implementation-plan

name	executing-an-implementation-plan
description	Use when executing implementation plans with independent tasks in the current session - dispatches fresh subagent for each task, reviews once per phase, loads phases just-in-time to minimize context usage

Executing an Implementation Plan

Execute plan phase-by-phase, loading each phase just-in-time to minimize context usage.

Core principle: Read one phase → execute all tasks → review → move to next phase. Never load all phases upfront.

REQUIRED SKILL: requesting-code-review - The review loop (dispatch, fix, re-review until zero issues)

Overview

When NOT to use:

• No implementation plan exists yet (use writing-implementation-plans first)
• Plan needs revision (brainstorm first)
• Several independent items (bugs / tickets) to ship in parallel — use executing-parallel-issue-sweep instead. That skill dispatches one self-contained owner per item; each owner runs its own implement/review/fix/PR loop, so items iterate truly in parallel instead of waiting at each phase's review gate.

MANDATORY: Human Transparency

The human cannot see what subagents return. You are their window into the work.

After EVERY subagent completes (task-implementor, bug-fixer, ed3d-code-reviewer), you MUST:

1. Print the subagent's full response to the user before taking any other action
2. Do not summarize or paraphrase - show them what the subagent actually said
3. Include all details: test counts, issue lists, commit hashes, error messages

Before dispatching any subagent:

• Briefly explain (2-3 sentences) what you're asking the agent to do
• State which phase this covers

Why this matters: When you silently process subagent output without showing the user, they lose visibility into their own codebase. They can't catch errors, learn from the process, or intervene when needed. Transparency is not optional.

Red flag: If you find yourself thinking "I'll just move on to the next step" without printing the subagent's response, STOP. Print it first.

REQUIRED: Implementation Plan Path

DO NOT GUESS. If the user has not provided a path to an implementation plan directory, you MUST ask for it.

Use the question tool:

Question: "Which implementation plan should I execute?"
Options:
  - [list any plan directories you find in docs/implementation-plans/]
  - "Let me provide the path"

If docs/implementation-plans/ doesn't exist or is empty, ask the user to provide the path directly.

Never assume, infer, or guess which plan to execute. The user must explicitly tell you.

The Process

1. Discover Phases

DO NOT read the full phase files yet. List them and read only the header and task markers.

# List phase files
ls [plan-directory]/phase_*.md

# For each file, get the header (first 10 lines include title and Goal)
head -10 [plan-directory]/phase_01.md

# Get task/subcomponent structure without reading full content
grep -E "START_TASK_|START_SUBCOMPONENT_" [plan-directory]/phase_01.md

The header includes the title (# [Phase Title]) and **Goal:** line. Extract the title for the todo entry.

The grep output shows the task structure, e.g.:

<!-- START_TASK_1 -->
<!-- START_TASK_2 -->
<!-- START_SUBCOMPONENT_A (tasks 3-5) -->
<!-- START_TASK_3 -->
<!-- START_TASK_4 -->
<!-- START_TASK_5 -->

Examples of headers you might see:

• # Document Infrastructure Implementation Plan — Phase 1 implied
• # Phase 4: Link Resolution — Phase number explicit

Check for implementation guidance:

After discovering phases, check if .ed3d/implementation-plan-guidance.md exists in the project root:

# Check for implementation guidance (note the absolute path for later use)
ls [project-root]/.ed3d/implementation-plan-guidance.md

If the file exists, note its absolute path for use during code reviews. If it doesn't exist, proceed without it—do not pass a nonexistent path to reviewers.

Check for test requirements:

Check if test-requirements.md exists in the plan directory:

# Check for test requirements (note the absolute path for later use)
ls [plan-directory]/test-requirements.md

If the file exists, note its absolute path for use during final review. The test requirements document specifies what automated tests must exist for each acceptance criterion.

Create a session-isolated scratchpad directory:

# Extract slug from plan directory name (last path component, without trailing slash)
SLUG=$(basename "[plan-directory]")
# Generate unique session ID
SESSION_ID=$(printf '%04x%04x' $RANDOM $RANDOM)
# Create scratchpad path
SCRATCHPAD_DIR="/tmp/exec-${SLUG}-${SESSION_ID}"
mkdir -p "${SCRATCHPAD_DIR}"
echo "${SCRATCHPAD_DIR}"

This scratchpad ensures isolation when multiple execution sessions run in parallel. Pass it to ed3d-code-reviewer invocations.

2. Create Phase-Level Todo List

Use todowrite to create three todo entries per phase. Include the title from the header:

- [ ] Phase 1a: Read /absolute/path/to/phase_01.md — Document Infrastructure Implementation Plan
- [ ] Phase 1b: Execute tasks
- [ ] Phase 1c: Code review
- [ ] Phase 2a: Read /absolute/path/to/phase_02.md — API Integration
- [ ] Phase 2b: Execute tasks
- [ ] Phase 2c: Code review
...

Why absolute paths in todo entries: After compaction, context may be summarized. The absolute path in the todo entry ensures you always know exactly which file to read.

Why include the title: Gives visibility into what each phase covers without loading full content.

3. Execute Each Phase

For each phase, follow this cycle:

3a. Read Phase File (just-in-time)

Mark "Phase Na: Read [path]" as in_progress.

Read ONLY that phase file now. Extract:

• List of tasks in this phase
• Working directory
• Any phase-specific context

Mark "Phase Na: Read" as complete.

3b. Execute All Tasks

Mark "Phase Nb: Execute tasks" as in_progress.

Before dispatching, verify test coverage for functionality tasks:

If a functionality task (code that does something) has no tests specified:

1. Check if a subsequent task in the same phase provides tests
2. If no tests exist anywhere for this functionality → STOP
3. This is a plan gap. Surface to user: "Task N implements [functionality] but no corresponding tests exist in the plan. This needs tests before implementation."

Do NOT implement functionality without tests. Missing tests = plan gap, not something to skip.

Execute all tasks in sequence. For each task, dispatch ed3d-task-implementor-fast with the phase file path:

task:
  subagent_type: ed3d-task-implementor-fast
  description: Implementing Phase X, Task Y: [description]
  prompt: |
    Implement Task N from the phase file.

    Phase file: [absolute path to phase file]
    Task number: N

    Read the phase file and implement Task N (look for `<!-- START_TASK_N -->`).

    Your job is to:
    1. Read the phase file to understand context
    2. Apply all relevant skills, such as (if available) coding-effectively
    3. Implement exactly what Task N specifies
    4. Verify with tests/build/lint
    5. Commit your work
    6. Report back with evidence

    Work from: [directory]

    Provide complete report per your agent instructions.

For subcomponents (grouped tasks), dispatch once for all tasks in the subcomponent:

task:
  subagent_type: ed3d-task-implementor-fast
  description: Implementing Phase X, Subcomponent A (Tasks 3-5): [description]
  prompt: |
    Implement Subcomponent A (Tasks 3, 4, 5) from the phase file.

    Phase file: [absolute path to phase file]
    Tasks: 3, 4, 5 (look for `<!-- START_SUBCOMPONENT_A -->`)

    Read the phase file and implement all tasks in this subcomponent.

    Your job is to:
    1. Read the phase file to understand context
    2. Apply all relevant skills, such as (if available) coding-effectively
    3. Implement all tasks in sequence
    4. Verify with tests/build/lint after completing all tasks
    5. Commit your work (one commit per task, or logical commits)
    6. Report back with evidence for each task

    Work from: [directory]

    Provide complete report covering all tasks.

Print each task-implementor's response before moving to the next task.

No code review between tasks. Execute all tasks in the phase first.

After all tasks complete, mark "Phase Nb: Execute tasks" as complete.

3c. Code Review for Phase

Mark "Phase Nc: Code review" as in_progress.

MANDATORY: Use the requesting-code-review skill for the review loop.

Context to provide:

• WHAT_WAS_IMPLEMENTED: Summary of all tasks in this phase
• PLAN_OR_REQUIREMENTS: All tasks from this phase
• BASE_SHA: commit before phase started
• HEAD_SHA: current commit
• IMPLEMENTATION_GUIDANCE: absolute path to .ed3d/implementation-plan-guidance.md (only if it exists—omit entirely if the file doesn't exist)
• SCRATCHPAD_DIR: session-isolated temp directory for code reviewer scratch files

The implementation guidance file contains project-specific coding standards, testing requirements, and review criteria. When provided, the code reviewer should read it and apply those standards during review.

Note: Test requirements validation happens at final review, not per-phase. Per-phase reviews focus on code quality and whether the phase includes tests for its functionality.

If code reviewer returns a context limit error:

The phase changed too much for a single review. Chunk the review:

1. Identify the midpoint of tasks in the phase
2. Run code review for first half of tasks (commits for tasks 1 through N/2)
3. Fix any issues found
4. Run code review for second half of tasks (commits for tasks N/2+1 through N)
5. Fix any issues found

When issues are found:

1. Create a todo for EACH issue (survives compaction). Add them with todowrite, and place the re-review todo last:

   - Phase N fix [Critical]: <VERBATIM issue description from reviewer>
   - Phase N fix [Important]: <VERBATIM issue description from reviewer>
   - Phase N fix [Minor]: <VERBATIM issue description from reviewer>
   ...one todo per issue...
   - Phase N: Re-review after fixes
   

   The "Re-review after fixes" todo comes after all fix todos in the list — only start it once every fix todo is completed.

   Copy issue descriptions VERBATIM, even if long. After compaction, the todo content is all that remains — it must contain the full issue details for the bug-fixer to understand what to fix.

2. Dispatch ed3d-task-bug-fixer with the phase file:

task:
  subagent_type: ed3d-task-bug-fixer
  description: Fixing review issues for Phase X
  prompt: |
    Fix issues from code review for Phase X.

    Phase file: [absolute path to phase file]

    Code reviewer found these issues:
    [list all issues - Critical, Important, and Minor]

    Read the phase file to understand the tasks and context.

    Your job is to:
    1. Understand root cause of each issue
    2. Apply fixes systematically (Critical → Important → Minor)
    3. Verify with tests/build/lint
    4. Commit your fixes
    5. Report back with evidence

    Work from: [directory]

    Fix ALL issues — including every Minor issue. The goal is ZERO issues on re-review.
    Minor issues are not optional. Do not skip them.

3. Mark "Fix issues" complete, then re-review per the requesting-code-review skill.

4. If re-review finds more issues, create new fix/re-review todos. Continue loop until zero issues.

5. Mark "Re-review" complete when zero issues.

Plan execution policy (stricter than general code review):

• ALL issues must be fixed (Critical, Important, AND Minor)
• Ignore APPROVED/BLOCKED status - count issues only
• Three-strike rule: If same issues persist after three review cycles, stop and ask human for help

Minor issues are NOT optional. Do not rationalize skipping them with "they're just style issues" or "we can fix those later." The reviewer flagged them for a reason. Fix every single one.

Exit condition: Zero issues in all categories — including Minor.

Mark "Phase Nc: Code review" as complete.

3d. Move to Next Phase

Proceed to the next phase's "Read" step. Repeat 3a-3c for each phase.

4. Update Project Context

After all phases complete, invoke the ed3d-project-opencode-librarian subagent (when available) to review changes and update AGENTS.md files if needed.

task:
  subagent_type: ed3d-project-opencode-librarian
  description: Updating project context after implementation
  prompt: |
    Review what changed during this implementation and update AGENTS.md files if contracts or structure changed.

    Base commit: <commit SHA at start of first phase>
    Current HEAD: <current commit>
    Working directory: <directory>

    Follow the maintaining-project-context skill to:
    1. Diff against base to see what changed
    2. Identify contract/API/structure changes
    3. Update affected AGENTS.md files
    4. Commit documentation updates

    Report back with what was updated (or that no updates were needed).

If librarian reports updates: Review the changes, then proceed to final review. If librarian reports no updates needed: Proceed to final review. If librarian subagent is unavailable: skip this entire step. Say aloud that you're skipping it because the ed3d-project-opencode-librarian agent is not available.

5. Final Review Sequence

After all phases complete, run a sequence of specialized agents:

Code Review → Test Analysis (Coverage + Plan)

5a. Final Code Review

Use the requesting-code-review skill for final code review:

Context to provide:

• WHAT_WAS_IMPLEMENTED: Summary of all phases completed
• PLAN_OR_REQUIREMENTS: Reference to the full implementation plan directory
• BASE_SHA: commit before first phase started
• HEAD_SHA: current commit
• IMPLEMENTATION_GUIDANCE: absolute path (if exists)
• SCRATCHPAD_DIR: session-isolated temp directory for code reviewer scratch files
• AC_COVERAGE_CHECK: "Verify all acceptance criteria (using scoped format {slug}.AC*) from the design plan are covered by at least one phase. Flag any ACs not addressed."

Continue the review loop until zero issues remain.

5b. Test Analysis

Only after final code review passes with zero issues.

Skip this step if test-requirements.md does not exist.

The ed3d-test-analyst agent performs two sequential tasks with shared analysis:

1. Validate coverage against acceptance criteria
2. Generate human test plan (only if coverage passes)

Dispatch the ed3d-test-analyst agent:

task:
  subagent_type: ed3d-test-analyst
  description: Analyzing test coverage and generating test plan
  prompt: |
    Analyze test implementation against acceptance criteria.

    TEST_REQUIREMENTS_PATH: [absolute path to test-requirements.md]
    WORKING_DIRECTORY: [project root]
    BASE_SHA: [commit before first phase]
    HEAD_SHA: [current commit]

    Phase 1: Validate that automated tests exist for all acceptance criteria.
    Phase 2: If coverage passes, generate human test plan using your analysis.

    Return coverage validation result. If PASS, include the human test plan.

If analyst returns coverage FAIL:

1. Dispatch bug-fixer to add missing tests:

   task:
     subagent_type: ed3d-task-bug-fixer
     description: Adding missing test coverage
     prompt: |
       Add missing tests identified by the test analyst.
   
       Missing coverage:
       [list from analyst output]
   
       For each missing test:
       1. Read the acceptance criterion carefully
       2. Create the test file at the expected location
       3. Write tests that verify the criterion's actual behavior—not just code that passes, but code that would fail if the criterion weren't met
       4. Run tests to confirm they pass
       5. Commit the new tests
   
       Work from: [directory]
   

2. Re-run ed3d-test-analyst

3. Repeat until coverage PASS or three attempts fail (then escalate to human)

If analyst returns coverage PASS:

The response will include the human test plan. Extract the "Human Test Plan" section.

Write the test plan:

# Create test-plans directory if needed
mkdir -p docs/test-plans

# The filename uses the implementation plan directory name
# e.g., impl plan dir: docs/implementation-plans/2025-01-24-oauth/
#       test plan:     docs/test-plans/2025-01-24-oauth.md

Write the test plan content to docs/test-plans/[impl-plan-dir-name].md, then commit:

git add docs/test-plans/[impl-plan-dir-name].md
git commit -m "docs: add test plan for [feature name]"

Announce: "Human test plan written to docs/test-plans/[impl-plan-dir-name].md"

6. Complete Development

After final review passes:

• Provide a report to the human operator

  • For each phase:
    • How many tasks were implemented
    • How many review cycles were needed
    • Any compromises made (there should be NO compromises, but if any were made). Examples:
      • "I couldn't run the integration tests, so I continued on"
      • "I couldn't generate the client because the dev environment was down"
      • Note that these are PARTIAL FAILURE CASES and explain to the user what the user must do now.
    • Were any code-review issues left outstanding at any point?

• Activate the finishing-a-development-branch skill. DO NOT activate it before this point.

Example Workflow

You: I'm using the `executing-an-implementation-plan` skill.

[Discover phases: phase_01.md, phase_02.md, phase_03.md]
[Read first 3 lines of each to get titles]

[Create todos with todowrite:]
- [ ] Phase 1a: Read /path/to/phase_01.md — Project Setup
- [ ] Phase 1b: Execute tasks
- [ ] Phase 1c: Code review
- [ ] Phase 2a: Read /path/to/phase_02.md — Token Service
- [ ] Phase 2b: Execute tasks
- [ ] Phase 2c: Code review
- [ ] Phase 3a: Read /path/to/phase_03.md — API Middleware
- [ ] Phase 3b: Execute tasks
- [ ] Phase 3c: Code review

--- Phase 1 ---

[Mark 1a in_progress, read phase_01.md]
→ Contains 2 tasks: project setup, config files

[Mark 1a complete, 1b in_progress]

[Dispatch ed3d-task-implementor-fast for Task 1]
→ Created package.json, tsconfig.json.

[Dispatch ed3d-task-implementor-fast for Task 2]
→ Created config files. Build succeeds.

[Mark 1b complete, 1c in_progress]

[Use requesting-code-review skill for phase 1]
→ Zero issues.

[Mark 1c complete]

--- Phase 2 ---

[Mark 2a in_progress, read phase_02.md]
→ Contains 3 tasks: types, service, tests

[Mark 2a complete, 2b in_progress]

[Execute all 3 tasks...]

[Mark 2b complete, 2c in_progress]

[Use requesting-code-review skill for phase 2]
→ Important: 1, Minor: 1
→ Dispatch bug-fixer, re-review
→ Zero issues.

[Mark 2c complete]

--- Phase 3 ---

[Similar pattern...]

--- Finalize ---

[Invoke ed3d-project-opencode-librarian subagent]
→ Updated AGENTS.md.

[Use requesting-code-review skill for final review]
→ All requirements met.

[Transitioning to finishing-a-development-branch]

Common Rationalizations - STOP

Excuse	Reality
"I'll read all phases upfront to understand the full picture"	No. Read one phase at a time. Context limits are real.
"I'll skip the read step, I remember what's in the file"	No. Always read just-in-time. Context may have been compacted.
"I'll review after each task to catch issues early"	No. Review once per phase. Task-level review wastes context.
"Context error on review, I'll skip the review"	No. Chunk the review into halves. Never skip review.
"Minor issues can wait"	No. Fix ALL issues including Minor.