preflight

name	preflight
description	Use before starting delivery work. Pre-implementation validation checklist to ensure readiness.
metadata	{"instruction_budget":"45","framework_dependency":"mycelium","framework_dependency_note":"This skill is designed to run within the Mycelium framework (https://github.com/haabe/mycelium). Standalone use will skip the canvas state, theory gates, and harness behavior the skill assumes. Install: /plugin install mycelium@haabe-mycelium."}

Preflight Skill

Pre-delivery validation checklist. Run before every implementation task.

Checklist

Constraints (ALWAYS FIRST)

Before scoping any delivery work, establish constraints. Do not propose a plan before knowing the budget.

• Time budget: "How much time do you have for this?" (hours, days, sprint length)
• Resource constraints: Solo? Team? What skills are available?
• Fidelity: Demo/prototype vs. production? Who is the audience?
• Dependencies: Waiting on anything external?

If time budget < 8 hours, scope aggressively — one vertical slice, no polish. If the initial plan exceeds the time budget, cut scope before presenting it to the user.

Re-forecast trigger (audit-triggered / emergent work). Work that opens as "just address the recommendations", "quick fix", or any audit/assessment follow-up still gets a constraint pass — set an explicit estimate even when no one asked for one. Then, mid-session, re-forecast when the work crosses ~2× the estimate or when no estimate was ever set: stop, state actual-so-far vs estimate, and re-scope or re-confirm the budget before continuing. The failure this catches: emergent cycles that bypass preflight and balloon silently (dogfood cycle-history.yml — a "~2h" audit cycle ran ~9h; a "session-scope" one ran ~14h). The re-forecast becomes the calibration.effort_accuracy data point at /retrospective.

Source: Hoskins transcript (2026-04-25) — agent proposed 20-hour plan before learning user had 8 hours. Goldratt (Theory of Constraints — identify the constraint before optimizing). Corrections.md: "Over-scope before constraints." Re-forecast trigger from the 2026-06-15 /framework-health effort-calibration finding (audit-triggered cycles balloon past estimate).

Context

• corrections.md reviewed for relevant past mistakes
• patterns.md reviewed for applicable patterns
• Current diamond phase is Develop or Deliver
• Acceptance criteria are clear and measurable
• Scenarios linked: .claude/canvas/scenarios.yml has scenarios for this solution, and acceptance criteria trace back to scenario success/failure states (Hoskins)

Scope

• Scope fits within the time budget declared above
• This is the smallest vertical slice that delivers value
• Scope is explicitly bounded (what is NOT included)
• No speculative features (YAGNI check)
• Dependencies identified and available

Technical / Production Readiness

Software/AI tool:

• Tech stack detected and understood
• Build/test/lint commands confirmed working
• Development environment functional
• Existing code patterns reviewed

Content:

• Production tools ready (editor, recording, hosting)
• Style guide / editorial standards available
• Existing content patterns reviewed

Service:

• Delivery tools ready (templates, scheduling, communication)
• Existing service patterns reviewed

Security (software, ai_tool, service with digital infra)

• Data classification understood for this feature
• Security requirements identified (auth, input validation, etc.)
• No secrets will be hardcoded
• Dependencies checked for known vulnerabilities

Accessibility

Software:

• Accessibility requirements identified
• Semantic HTML approach planned
• Keyboard interaction model defined
• Color contrast requirements noted

Content:

• Captions/transcripts planned for audio/video
• Alt text planned for images
• Readable typography confirmed

Validation Strategy

Software: Test approach defined (unit, integration, e2e), edge cases and error scenarios identified. Content: Review process defined (SME, self-checklist, fact-check), learning objectives mapped. AI tool: Eval test cases defined, red-team scenarios planned, bias testing approach chosen. Service: Walkthrough planned, client feedback mechanism defined.

Success Criteria (G-V11)

• Declare what will be true after this delivery increment (1-3 measurable statements)
• Declare how each criterion will be verified (test, manual check, metric)
• Record criteria in .claude/harness/decision-log.md alongside the delivery decision

Example:

Success criteria:
1. "Users can complete onboarding in < 5 min" — verified by usability test
2. "API responds in < 200ms at p95" — verified by load test
3. "No new lint or type errors introduced" — verified by CI

Definition of Done

• DoD criteria reviewed and understood
• All criteria are achievable within this task

If Any Item Fails

Do not proceed to implementation. Instead:

1. Document what is missing.
2. Determine the fastest path to readiness.
3. Address the gap before starting delivery work.

Theory Citations

• Smart: BVSSH (Sooner -- avoid rework by preparing)
• Forsgren: Accelerate (reduce lead time by removing blockers early)