# Deep Plan > Deep structured analysis and planning with script-enforced quality gates. Use when the user explicitly asks for deep planning, thorough analysis before a complex decision, or invokes /deep-plan. Also use when a task involves cross-service architecture, migration strategy, or multi-stakeholder tradeoffs that need rigorous reasoning before implementation. Not needed for routine Plan/Code workflow — that is handled by plan-code-workflow. - Skill: `est7/deep-plan` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add est7/deep-plan` - Raw SKILL.md: https://api.skillmd.com/api/skills/est7/deep-plan/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Product & Planning - Author: est7 (https://skillmd.com/u/est7) - Updated: 2026-09-10 - Page: https://skillmd.com/skills/est7/deep-plan --- # Deep Plan Structured deep analysis with **script-enforced output gates**. Unlike prompt-only self-checks, this skill validates thinking quality programmatically — the validator script parses your output and rejects incomplete analysis. ## When to use this vs plan-code-workflow - **plan-code-workflow**: organizing what to build and how — Plan mode → Code mode - **deep-plan**: rigorous reasoning *before* deciding what to build — when the decision itself is the hard part Use deep-plan first, then hand off to plan-code-workflow for execution. --- ## Phase 1 — Complexity Assessment Classify the task: | Level | Criteria | Min Steps | |-------|----------|-----------| | simple | Single file/function, no cross-module impact | 3 | | medium | Multi-file/module, design choices needed | 5 | | complex | Cross-service, architecture tradeoffs, migration | 8 | Output the complexity level and your initial step count estimate. This determines the validator's minimum step threshold. --- ## Phase 2 — Sequential Thinking Output numbered thinking steps. Each step MUST use this exact format: ``` ### Step N/M [tag] - **Focus**: What this step analyzes (one concern per step) - **Findings**: Observations, evidence, conclusions - **Confidence**: high | medium | low - **Next**: What the next step addresses (or "→ Gate" on final step) ``` ### Tags | Tag | When to use | |-----|-------------| | `analysis` | Examining a specific aspect | | `decomposition` | Breaking problem into sub-problems | | `evaluation` | Assessing an approach or alternative | | `comparison` | Comparing options side-by-side | | `revision` | Revising a previous step — use `[revision of Step X]` | | `branch` | Exploring an alternative path — use `[branch: id]` | | `synthesis` | Combining findings into a conclusion | ### Rules 1. **One concern per step.** Do not combine multiple analyses. 2. **Adjust M freely.** Add steps as understanding deepens; reduce if a path is clearly simpler. 3. **Revise explicitly.** When new evidence contradicts an earlier step, tag as `revision` and cite which step. 4. **Address low confidence.** Any step with `Confidence: low` must be followed up by a later step that resolves the uncertainty. 5. **Terminate with "→ Gate".** The final step's Next field must say "→ Gate" to signal readiness for validation. ### Required coverage Your steps must collectively cover all of these (order is flexible): 1. **Problem definition** — core problem, constraints, success criteria 2. **Decomposition** — sub-problems (MECE: mutually exclusive, collectively exhaustive) 3. **Evaluation** — at least 1 alternative approach assessed (or explicit justification why only 1 viable path exists) 4. **Tradeoff comparison** — tabular comparison on ≥3 dimensions (when alternatives exist) 5. **Execution steps** — 4–10 ordered, concrete, verifiable actions 6. **Risks** — issues and concrete mitigations --- ## Phase 3 — Validation Gate (Script-Enforced) After completing all thinking steps, synthesize into a plan document and run the validator. ### Step 3a — Write the plan to a temp file Write to `/tmp/deep-plan-output.md` containing both your thinking steps AND the plan: ```markdown complexity: (All your ### Step N/M [tag] blocks from Phase 2) ## Plan: {task title} ### Problem Definition - **Core problem**: ... - **Constraints**: ... - **Success criteria**: ... ### Analysis Summary Key findings referencing step numbers. ### Execution Plan 1. Step — description → verification method 2. Step — description → verification method ... ### Risks - Risk → mitigation ### Open Questions - [ ] Assumptions needing confirmation ``` ### Step 3b — Run the validator ```bash python /scripts/validate_plan.py /tmp/deep-plan-output.md ``` The script checks 8 gates: | Gate | What it checks | |------|---------------| | `step_format` | Every step has Focus, Findings, Confidence, Next | | `step_tags` | All tags are from the valid set | | `coverage` | All required topics addressed | | `termination` | Final step ends with "→ Gate" | | `low_confidence_addressed` | Low-confidence steps resolved later | | `plan_sections` | Plan has all required sections | | `execution_verification` | Every execution step has a verification method | | `minimum_steps` | Step count meets complexity threshold | ### Step 3c — Handle results - **All gates pass** → proceed to Phase 4 - **Any gate fails** → read the failure details, add thinking steps to fill the gaps, rewrite the plan, rerun the validator. Repeat until all gates pass. Do NOT proceed with failing gates. --- ## Phase 4 — Review Gate (Human) Present the validated plan to the user. Then pause with AskUserQuestion: - "Approve — proceed to execute" - "Adjust — specify what to change" - "Abort — discard this plan" Do NOT proceed without explicit approval. --- ## Phase 5 — Persist and Execute Only after approval: 1. Write plan to `plan/YYYY-MM-DD_HH-mm-ss-.md` with frontmatter: ```yaml --- mode: plan task: complexity: created_at: validated: true --- ``` 2. Execute the plan step by step. --- ## Session Continuity - "adjust", "modify", "refine" → update plan, re-validate, re-enter Phase 4 - "new", "different task" → restart from Phase 1 - Uncertain → ask the user