implement-plan-preflight

Execute the Preflight phase of the /itp:go workflow. Creates ADR and Design Spec artifacts with proper cross-linking and verification.

Self-Evolving Skill: This skill improves through use. If instructions are wrong, parameters drifted, or a workaround was needed — fix this file immediately, don't defer. Only update for real, reproducible issues.

When to Use This Skill

• Invoked by /itp:go command during Preflight phase
• User asks to create an ADR for a feature
• User mentions "design spec" or "MADR format"
• Manual preflight verification needed

Preflight Workflow Overview

P.1: Create Feature Branch (if -b flag)
         │
         ▼
P.2: Create ADR File (MADR 4.0)
         │
         ▼
P.3: Create Design Spec (from global plan)
         │
         ▼
P.4: Verify Checkpoint (MANDATORY)

CRITICAL: Do NOT proceed to Phase 1 implementation until ALL preflight steps are complete and verified.

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Quick Reference

ADR ID Format

YYYY-MM-DD-slug

Example: 2025-12-01-clickhouse-aws-ohlcv-ingestion

File Locations

| Artifact | Path | | ----------- | ------------------------------------ | | ADR | /docs/adr/$ADR_ID.md | | Design Spec | /docs/design/$ADR_ID/spec.md | | Global Plan | ~/.claude/plans/<adj-verb-noun>.md |

Cross-Links (MANDATORY)

In ADR header:

**Design Spec**: [Implementation Spec](/docs/design/YYYY-MM-DD-slug/spec.md)

In spec.md header:

**ADR**: [Feature Name ADR](/docs/adr/YYYY-MM-DD-slug.md)

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Execution Steps

Step P.1: Create Feature Branch (Optional)

Only if -b flag specified. See Workflow Steps for details.

Step P.2: Create ADR File

1. Create /docs/adr/$ADR_ID.md
2. Use template from ADR Template
3. Populate frontmatter from session context
4. Select perspectives from Perspectives Taxonomy

Step P.3: Create Design Spec

1. Create folder: mkdir -p docs/design/$ADR_ID
2. Copy global plan: cp ~/.claude/plans/<adj-verb-noun>.md docs/design/$ADR_ID/spec.md
3. Add ADR backlink to spec header

Step P.4: Verify Checkpoint

Run validator or manual checklist:

uv run scripts/preflight_validator.py $ADR_ID

Checklist (ALL must be true):

• [ ] ADR file exists at /docs/adr/$ADR_ID.md
• [ ] ADR has YAML frontmatter with all 7 required fields
• [ ] ADR has **Design Spec**: link in header
• [ ] DIAGRAM CHECK 1: ADR has Before/After diagram (Context section)
• [ ] DIAGRAM CHECK 2: ADR has Architecture diagram (Architecture section)
• [ ] Design spec exists at /docs/design/$ADR_ID/spec.md
• [ ] Design spec has **ADR**: backlink in header

If any item is missing: Create it now. Do NOT proceed to Phase 1.

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YAML Frontmatter Quick Reference

---
status: proposed
date: YYYY-MM-DD
decision-maker: [User Name]
consulted: [Agent-1, Agent-2]
research-method: single-agent
clarification-iterations: N
perspectives: [Perspective1, Perspective2]
---

See ADR Template for full field descriptions.

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Diagram Requirements (2 DIAGRAMS REQUIRED)

⛔ MANDATORY: Every ADR must include EXACTLY 2 diagrams:

| Diagram | Location | Purpose | | ---------------- | -------------------- | ----------------------------- | | Before/After | Context section | Shows system state change | | Architecture | Architecture section | Shows component relationships |

BLOCKING GATE: Do NOT proceed to design spec until BOTH diagrams are embedded in ADR.

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Reference Documentation

• ADR Template - Complete MADR 4.0 template
• Perspectives Taxonomy - 11 perspective types
• Workflow Steps - Detailed step-by-step guide

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Validation Script

# Verify preflight artifacts
uv run scripts/preflight_validator.py <adr-id>

# Example
uv run scripts/preflight_validator.py 2025-12-01-my-feature

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Troubleshooting

| Issue | Cause | Solution | | --------------------- | ----------------------- | -------------------------------------------- | | Validator fails | Missing ADR or spec | Create both files before running validator | | Frontmatter invalid | Missing required fields | Check all 7 ADR fields and 5 spec fields | | Spec phase mismatch | Wrong phase value | Use: preflight, phase-1, phase-2, or phase-3 | | ADR status wrong | Manual status edit | Let workflow manage status transitions | | Design folder missing | Wrong path structure | Use docs/design/YYYY-MM-DD-slug/spec.md |

Post-Execution Reflection

After this skill completes, check before closing:

1. Did the command succeed? — If not, fix the instruction or error table that caused the failure.
2. Did parameters or output change? — If the underlying tool's interface drifted, update Usage examples and Parameters table to match.
3. Was a workaround needed? — If you had to improvise (different flags, extra steps), update this SKILL.md so the next invocation doesn't need the same workaround.

Only update if the issue is real and reproducible — not speculative.