Writing Plans

<!-- Adapted from obra/superpowers — Tessera graph context + plan_save integration added -->

Overview

Write comprehensive implementation plans assuming the engineer has zero context for the codebase and questionable taste. Document everything they need: which files to touch, code, testing, docs, how to verify. Bite-sized tasks. DRY. YAGNI. TDD. Frequent commits.

Announce at start: "I'm using the writing-plans skill to create the implementation plan."

Save plans to: docs/plans/YYYY-MM-DD-<feature-name>.md

Phase 0: Tessera Context Load

If tessera MCP is configured in this session:

1. graph_continue (mandatory first call)
2. graph_retrieve with the feature's key terms
3. graph_read each recommended file (at high confidence: read all; medium/low: up to max_supplementary_files)
4. graph_action_summary — surface any locked decisions that constrain this plan

This grounds the file structure analysis in actual codebase reality before writing a single task.

Scope Check

If the spec covers multiple independent subsystems, suggest breaking into separate plans — one per subsystem. Each plan should produce working, testable software on its own.

File Structure

Before defining tasks, map out which files will be created or modified:

• Design units with clear boundaries and well-defined interfaces
• Prefer smaller, focused files over large ones
• Files that change together should live together
• In existing codebases (informed by graph_retrieve above), follow established patterns

Bite-Sized Task Granularity

Each step is one action (2-5 minutes):

• "Write the failing test" - step
• "Run it to make sure it fails" - step
• "Implement the minimal code to make the test pass" - step
• "Run the tests and make sure they pass" - step
• "Commit" - step

Plan Document Header

Every plan MUST start with this header:

# [Feature Name] Implementation Plan

> **For agentic workers:** REQUIRED SUB-SKILL: Use subagent-driven-development (recommended) or executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.

**Goal:** [One sentence describing what this builds]

**Architecture:** [2-3 sentences about approach]

**Tech Stack:** [Key technologies/libraries]

---

Task Structure

### Task N: [Component Name]

**Files:**
- Create: `exact/path/to/file.py`
- Modify: `exact/path/to/existing.py:123-145`
- Test: `tests/exact/path/to/test.py`

- [ ] **Step 1:** Write the failing test

def test_specific_behavior(): result = function(input) assert result == expected

- [ ] **Step 2:** Run test to verify it fails

Run: `pytest tests/path/test.py::test_name -v`
Expected: FAIL with "function not defined"

- [ ] **Step 3:** Write minimal implementation

- [ ] **Step 4:** Run test to verify it passes

- [ ] **Step 5:** Commit

No Placeholders

Every step must contain the actual content an engineer needs. Never write:

• "TBD", "TODO", "implement later"
• "Add appropriate error handling" (without showing the code)
• "Write tests for the above" (without actual test code)
• "Similar to Task N" (repeat the code — engineer may be reading tasks out of order)

Self-Review

After writing the complete plan, check against the spec:

1. Spec coverage: Can you point to a task that implements each requirement?
2. Placeholder scan: Any red flags from the list above?
3. Type consistency: Do method signatures match across tasks?

Fix inline. No need to re-review.

Phase 5.5: Codex Plan Review (Complexity Heuristic)

Auto-triggers if ANY of:

• Plan has >3 tasks
• Plan modifies >5 files
• Touches auth, payments, security, DB schema, API contracts, migrations
• User says "debate", "codex review", or uses --debate

Skips for: small plans (≤3 tasks, ≤5 files), doc-only, UI-only. Force off with --no-debate.

When triggered, after self-review but before archiving:

codex exec "Review this implementation plan. Plan: <PLAN_MARKDOWN>. Identify: missing steps, sequencing errors, security holes, integration risks, untested edge cases. Per issue: [CRITICAL|HIGH|MED|LOW]: <issue> — <suggested fix>. End with VERDICT: approved | needs_revision."

1. Fix all CRITICAL and HIGH issues inline in the plan.
2. Apply judgment to MED/LOW.
3. Append a "Codex Review Summary" section at the end of the plan:

• Verdict
• Issues fixed
• Issues deferred (with reason)

Then proceed to plan_save with the revised plan.

Archive with Tessera

After the plan is written and self-reviewed — if tessera MCP is configured:

Call the plan_save MCP tool:

plan_save(
  project_name = "<short project identifier>",
  subtask_name = "<feature or subtask name>",
  task         = "<one sentence describing what the plan builds>",
  plan_markdown = "<full plan markdown content>"
)

This registers the plan in Tessera's SQLite archive, parses the - [ ] checklist items, and enables tessera-verify to track compliance after implementation.

Save the returned `plan_id` — it appears in graph_continue output as active_checklist and is used by graph_register_edit to auto-mark tasks complete.

Execution Handoff

After saving the plan, offer execution choice:

"Plan complete and saved to `docs/plans/<filename>.md`. Two execution options:

1. Subagent-Driven (recommended) — Fresh subagent per task, two-stage review

2. Inline Execution — Execute tasks in this session with batch checkpoints

Which approach?"

• Subagent-Driven: invoke subagent-driven-development skill
• Inline Execution: invoke executing-plans skill