Phase Gate Validation

This skill validates whether the project is ready to advance to the next development phase. It checks for required artifacts, quality standards, and blockers.

Distinct from /project-stage-detect: That skill is diagnostic ("where are we?"). This skill is prescriptive ("are we ready to advance?" with a formal verdict).

Production Stages (7)

The project progresses through these stages:

1. Concept — Brainstorming, game concept document
2. Systems Design — Mapping systems, writing GDDs
3. Technical Setup — Engine config, architecture decisions
4. Pre-Production — Prototyping, vertical slice validation
5. Production — Feature development (Epic/Feature/Task tracking active)
6. Polish — Performance, playtesting, bug fixing
7. Release — Launch prep, certification

When a gate passes, write the new stage name to production/stage.txt (single line, e.g. Production). This updates the status line immediately.

1. Parse Arguments

Target phase: $ARGUMENTS[0] (blank = auto-detect current stage, then validate next transition)

Also resolve the review mode (once, store for all gate spawns this run):

1. If --review [full|lean|solo] was passed → use that
2. Else read production/review-mode.txt → use that value
3. Else → default to lean

Note: in solo mode, director spawns (CD-PHASE-GATE, TD-PHASE-GATE, PR-PHASE-GATE, AD-PHASE-GATE) are skipped — gate-check becomes artifact-existence checks only. In lean mode, all four directors still run (phase gates are the purpose of lean mode).

• With argument: /gate-check production — validate readiness for that specific phase

• No argument: Auto-detect current stage using the same heuristics as /project-stage-detect, then confirm with the user before running:

  Use AskUserQuestion:

  • Prompt: "Detected stage: [current stage]. Running gate for [Current] → [Next] transition. Is this correct?"
  • Options:
    • [A] Yes — run this gate
    • [B] No — pick a different gate (if selected, show a second widget listing all gate options: Concept → Systems Design, Systems Design → Technical Setup, Technical Setup → Pre-Production, Pre-Production → Production, Production → Polish, Polish → Release)

  Do not skip this confirmation step when no argument is provided.

2. Phase Gate Definitions

Gate: Concept → Systems Design

Required Artifacts:

• design/gdd/game-concept.md exists and has content
• Game pillars defined (in concept doc or design/gdd/game-pillars.md)
• Visual Identity Anchor section exists in design/gdd/game-concept.md (from brainstorm Phase 4 art-director output)

Quality Checks:

• Game concept has been reviewed (/design-review verdict not MAJOR REVISION NEEDED)
• Core loop is described and understood
• Target audience is identified
• Visual Identity Anchor contains a one-line visual rule and at least 2 supporting visual principles

Gate: Systems Design → Technical Setup

Required Artifacts:

• Systems index exists at design/gdd/systems-index.md with at least MVP systems enumerated
• All MVP-tier GDDs exist in design/gdd/ and individually pass /design-review
• A cross-GDD review report exists in design/gdd/ (from /review-all-gdds)

Quality Checks:

• All MVP GDDs pass individual design review (8 required sections, no MAJOR REVISION NEEDED verdict)
• /review-all-gdds verdict is not FAIL (cross-GDD consistency and design theory checks pass)
• All cross-GDD consistency issues flagged by /review-all-gdds are resolved or explicitly accepted
• System dependencies are mapped in the systems index and are bidirectionally consistent
• MVP priority tier is defined
• No stale GDD references flagged (older GDDs updated to reflect decisions made in later GDDs)

Gate: Technical Setup → Pre-Production

Required Artifacts:

• Engine chosen (CLAUDE.md Technology Stack is not [CHOOSE])
• Technical preferences configured (.claude/docs/technical-preferences.md populated)
• Art bible exists at design/art/art-bible.md with at least Sections 1–4 (Visual Identity Foundation)
• At least 3 Architecture Decision Records in docs/architecture/ covering Foundation-layer systems (scene management, event architecture, save/load)
• Engine reference docs exist in docs/engine-reference/[engine]/
• Test framework initialized: tests/unit/ and tests/integration/ directories exist
• CI/CD test workflow exists at .github/workflows/tests.yml (or equivalent)
• At least one example test file exists to confirm the framework is functional
• Master architecture document exists at docs/architecture/architecture.md
• Architecture traceability index exists at docs/architecture/architecture-traceability.md
• /architecture-review has been run (a review report file exists in docs/architecture/)
• design/accessibility-requirements.md exists with accessibility tier committed
• design/ux/interaction-patterns.md exists (pattern library initialized, even if minimal)

Quality Checks:

• Architecture decisions cover core systems (rendering, input, state management)
• Technical preferences have naming conventions and performance budgets set
• Accessibility tier is defined and documented (even "Basic" is acceptable — undefined is not)
• At least one screen's UX spec started (often the main menu or core HUD is designed during Technical Setup)
• All ADRs have an Engine Compatibility section with engine version stamped
• All ADRs have a GDD Requirements Addressed section with explicit GDD linkage
• No ADR references APIs listed in docs/engine-reference/[engine]/deprecated-apis.md
• All HIGH RISK engine domains (per VERSION.md) have been explicitly addressed in the architecture document or flagged as open questions
• Architecture traceability matrix has zero Foundation layer gaps (all Foundation requirements must have ADR coverage before Pre-Production)

ADR Circular Dependency Check: For all ADRs in docs/architecture/, read each ADR's "ADR Dependencies" / "Depends On" section. Build a dependency graph (ADR-A → ADR-B means A depends on B). If any cycle is detected (e.g. A→B→A, or A→B→C→A):

• Flag as FAIL: "Circular ADR dependency: [ADR-X] → [ADR-Y] → [ADR-X]. Neither can reach Accepted while the cycle exists. Remove one 'Depends On' edge to break the cycle."

Engine Validation (read docs/engine-reference/[engine]/VERSION.md first):

• ADRs that touch post-cutoff engine APIs are flagged with Knowledge Risk: HIGH/MEDIUM
• /architecture-review engine audit shows no deprecated API usage
• All ADRs agree on the same engine version (no stale version references)

Gate: Pre-Production → Production

Required Artifacts:

• At least 1 prototype in prototypes/ with a README
• First sprint plan exists in production/sprints/
• Art bible is complete (all 9 sections) and AD-ART-BIBLE sign-off verdict is recorded in design/art/art-bible.md
• Character visual profiles exist for key characters referenced in narrative docs
• All MVP-tier GDDs from systems index are complete
• Master architecture document exists at docs/architecture/architecture.md
• At least 3 ADRs covering Foundation-layer decisions exist in docs/architecture/
• Control manifest exists at docs/architecture/control-manifest.md (generated by /create-control-manifest from Accepted ADRs)
• Epics defined in production/epics/ with at least Foundation and Core layer epics present (use /create-epics layer: foundation and /create-epics layer: core to create them, then /create-stories [epic-slug] for each epic)
• Vertical Slice build exists and is playable (not just scope-defined)
• Vertical Slice has been playtested with at least 3 sessions (internal OK)
• Vertical Slice playtest report exists at production/playtests/ or equivalent
• UX specs exist for key screens: main menu, core gameplay HUD (at design/ux/), pause menu
• HUD design document exists at design/ux/hud.md (if game has in-game HUD)
• All key screen UX specs have passed /ux-review (verdict APPROVED or NEEDS REVISION accepted)

Quality Checks:

• Core loop fun is validated — playtest data confirms the central mechanic is enjoyable, not just functional. Explicitly check the Vertical Slice playtest report.
• UX specs cover all UI Requirements sections from MVP-tier GDDs
• Interaction pattern library documents patterns used in key screens
• Accessibility tier from design/accessibility-requirements.md is addressed in all key screen UX specs
• Sprint plan references real story file paths from production/epics/ (not just GDDs — stories must embed GDD req ID + ADR reference)
• Vertical Slice is COMPLETE, not just scoped — the build demonstrates the full core loop end-to-end. At least one complete [start → challenge → resolution] cycle works.
• Architecture document has no unresolved open questions in Foundation or Core layers
• All ADRs have Engine Compatibility sections stamped with the engine version
• All ADRs have ADR Dependencies sections (even if all fields are "None")
• Manual validation confirms GDDs + architecture + epics are coherent (run /review-all-gdds and /architecture-review if not done recently)
• Core fantasy is delivered — at least one playtester independently described an experience that matches the Player Fantasy section of the core system GDDs (without being prompted).

Vertical Slice Validation (FAIL if any item is NO):

• A human has played through the core loop without developer guidance
• The game communicates what to do within the first 2 minutes of play
• No critical "fun blocker" bugs exist in the Vertical Slice build
• The core mechanic feels good to interact with (this is a subjective check — ask the user)

Note: If any Vertical Slice Validation item is FAIL, the verdict is automatically FAIL regardless of other checks. Advancing without a validated Vertical Slice is the #1 cause of production failure in game development (per GDC postmortem data from 155 projects).

Gate: Production → Polish

Required Artifacts:

• src/ has active code organized into subsystems
• All core mechanics from GDD are implemented (cross-reference design/gdd/ with src/)
• Main gameplay path is playable end-to-end
• Test files exist in tests/unit/ and tests/integration/ covering Logic and Integration stories
• All Logic stories from this sprint have corresponding unit test files in tests/unit/
• Smoke check has been run with a PASS or PASS WITH WARNINGS verdict — report exists in production/qa/
• QA plan exists in production/qa/ (generated by /qa-plan) covering this sprint or final production sprint
• QA sign-off report exists in production/qa/ (generated by /team-qa) with verdict APPROVED or APPROVED WITH CONDITIONS
• At least 3 distinct playtest sessions documented in production/playtests/
• Playtest reports cover: new player experience, mid-game systems, and difficulty curve
• Fun hypothesis from Game Concept has been explicitly validated or revised

Quality Checks:

• Tests are passing (run test suite via Bash)
• No critical/blocker bugs in any bug tracker or known issues
• Core loop plays as designed (compare to GDD acceptance criteria)
• Performance is within budget (check technical-preferences.md targets)
• Playtest findings have been reviewed and critical fun issues addressed (not just documented)
• No "confusion loops" identified — no point in the game where >50% of playtesters got stuck without knowing why
• Difficulty curve matches the Difficulty Curve design doc (if one exists at design/difficulty-curve.md)
• All implemented screens have corresponding UX specs (no "designed in-code" screens)
• Interaction pattern library is up-to-date with all patterns used in implementation
• Accessibility compliance verified against committed tier in design/accessibility-requirements.md

Gate: Polish → Release

Required Artifacts:

• All features from milestone plan are implemented
• Content is complete (all levels, assets, dialogue referenced in design docs exist)
• Localization strings are externalized (no hardcoded player-facing text in src/)
• QA test plan exists (/qa-plan output in production/qa/)
• QA sign-off report exists (/team-qa output — APPROVED or APPROVED WITH CONDITIONS)
• All Must Have story test evidence is present (Logic/Integration: test files pass; Visual/Feel/UI: sign-off docs in production/qa/evidence/)
• Smoke check passes cleanly (PASS verdict) on the release candidate build
• No test regressions from previous sprint (test suite passes fully)
• Balance data has been reviewed (/balance-check run)
• Release checklist completed (/release-checklist or /launch-checklist run)
• Store metadata prepared (if applicable)
• Changelog / patch notes drafted

Quality Checks:

• Full QA pass signed off by qa-lead
• All tests passing
• Performance targets met across all target platforms
• No known critical, high, or medium-severity bugs
• Accessibility basics covered (remapping, text scaling if applicable)
• Localization verified for all target languages
• Legal requirements met (EULA, privacy policy, age ratings if applicable)
• Build compiles and packages cleanly

3. Run the Gate Check

Before running artifact checks, read docs/consistency-failures.md if it exists. Extract entries whose Domain matches the target phase (e.g., if checking Systems Design → Technical Setup, pull entries in Economy, Combat, or any GDD domain; if checking Technical Setup → Pre-Production, pull entries in Architecture, Engine). Carry these as context — recurring conflict patterns in the target domain warrant increased scrutiny on those specific checks.

For each item in the target gate:

Artifact Checks

• Use Glob and Read to verify files exist and have meaningful content
• Don't just check existence — verify the file has real content (not just a template header)
• For code checks, verify directory structure and file counts

Systems Design → Technical Setup gate — cross-GDD review check: Use Glob('design/gdd/gdd-cross-review-*.md') to find the /review-all-gdds report. If no file matches, mark the "cross-GDD review report exists" artifact as FAIL and surface it prominently: "No /review-all-gdds report found in design/gdd/. Run /review-all-gdds before advancing to Technical Setup." If a file is found, read it and check the verdict line: a FAIL verdict means the cross-GDD consistency check failed and must be resolved before advancing.

Quality Checks

• For test checks: Run the test suite via Bash if a test runner is configured
• For design review checks: Read the GDD and check for the 8 required sections
• For performance checks: Read technical-preferences.md and compare against any profiling data in tests/performance/ or recent /perf-profile output
• For localization checks: Grep for hardcoded strings in src/

Cross-Reference Checks

• Compare design/gdd/ documents against src/ implementations
• Check that every system referenced in architecture docs has corresponding code
• Verify sprint plans reference real work items

4. Collaborative Assessment

For items that can't be automatically verified, ask the user:

• "I can't automatically verify that the core loop plays well. Has it been playtested?"
• "No playtest report found. Has informal testing been done?"
• "Performance profiling data isn't available. Would you like to run /perf-profile?"

Never assume PASS for unverifiable items. Mark them as MANUAL CHECK NEEDED.

4b. Director Panel Assessment

Before generating the final verdict, spawn all four directors as parallel subagents via Task using the parallel gate protocol from .claude/docs/director-gates.md. Issue all four Task calls simultaneously — do not wait for one before starting the next.

Spawn in parallel:

1. creative-director — gate CD-PHASE-GATE (.claude/docs/director-gates.md)
2. technical-director — gate TD-PHASE-GATE (.claude/docs/director-gates.md)
3. producer — gate PR-PHASE-GATE (.claude/docs/director-gates.md)
4. art-director — gate AD-PHASE-GATE (.claude/docs/director-gates.md)

Pass to each: target phase name, list of artifacts present, and the context fields listed in that gate's definition.

Collect all four responses, then present the Director Panel summary:

## Director Panel Assessment

Creative Director:  [READY / CONCERNS / NOT READY]
  [feedback]

Technical Director: [READY / CONCERNS / NOT READY]
  [feedback]

Producer:           [READY / CONCERNS / NOT READY]
  [feedback]

Art Director:       [READY / CONCERNS / NOT READY]
  [feedback]

Apply to the verdict:

• Any director returns NOT READY → verdict is minimum FAIL (user may override with explicit acknowledgement)
• Any director returns CONCERNS → verdict is minimum CONCERNS
• All four READY → eligible for PASS (still subject to artifact and quality checks from Section 3)

5. Output the Verdict

## Gate Check: [Current Phase] → [Target Phase]

**Date**: [date]
**Checked by**: gate-check skill

### Required Artifacts: [X/Y present]
- [x] design/gdd/game-concept.md — exists, 2.4KB
- [ ] docs/architecture/ — MISSING (no ADRs found)
- [x] production/sprints/ — exists, 1 sprint plan

### Quality Checks: [X/Y passing]
- [x] GDD has 8/8 required sections
- [ ] Tests — FAILED (3 failures in tests/unit/)
- [?] Core loop playtested — MANUAL CHECK NEEDED

### Blockers
1. **No Architecture Decision Records** — Run `/architecture-decision` to create one
   covering core system architecture before entering production.
2. **3 test failures** — Fix failing tests in tests/unit/ before advancing.

### Recommendations
- [Priority actions to resolve blockers]
- [Optional improvements that aren't blocking]

### Verdict: [PASS / CONCERNS / FAIL]
- **PASS**: All required artifacts present, all quality checks passing
- **CONCERNS**: Minor gaps exist but can be addressed during the next phase
- **FAIL**: Critical blockers must be resolved before advancing

5a. Chain-of-Verification

After drafting the verdict in Phase 5, challenge it before finalising.

Step 1 — Generate 5 challenge questions designed to disprove the verdict:

For a PASS draft:

• "Which quality checks did I verify by actually reading a file, vs. inferring they passed?"
• "Are there MANUAL CHECK NEEDED items I marked PASS without user confirmation?"
• "Did I confirm all listed artifacts have real content, not just empty headers?"
• "Could any blocker I dismissed as minor actually prevent the phase from succeeding?"
• "Which single check am I least confident in, and why?"

For a CONCERNS draft:

• "Could any listed CONCERN be elevated to a blocker given the project's current state?"
• "Is the concern resolvable within the next phase, or does it compound over time?"
• "Did I soften any FAIL condition into a CONCERN to avoid a harder verdict?"
• "Are there artifacts I didn't check that could reveal additional blockers?"
• "Do all the CONCERNS together create a blocking problem even if each is minor alone?"

For a FAIL draft:

• "Have I accurately separated hard blockers from strong recommendations?"
• "Are there any PASS items I was too lenient about?"
• "Am I missing any additional blockers the user should know about?"
• "Can I provide a minimal path to PASS — the specific 3 things that must change?"
• "Is the fail condition resolvable, or does it indicate a deeper design problem?"

Step 2 — Answer each question independently. Do NOT reference the draft verdict text — re-check specific files or ask the user.

Step 3 — Revise if needed:

• If any answer reveals a missed blocker → upgrade verdict (PASS→CONCERNS or CONCERNS→FAIL)
• If any answer reveals an over-stated blocker → downgrade only if citing specific evidence
• If answers are consistent → confirm verdict unchanged

Step 4 — Note the verification in the final report output: Chain-of-Verification: [N] questions checked — verdict [unchanged | revised from X to Y]

6. Update Stage on PASS

When the verdict is PASS and the user confirms they want to advance:

1. Write the new stage name to production/stage.txt (single line, no trailing newline)
2. This immediately updates the status line for all future sessions

Example: if passing the "Pre-Production → Production" gate:

echo -n "Production" > production/stage.txt

Always ask before writing: "Gate passed. May I update production/stage.txt to 'Production'?"

7. Closing Next-Step Widget

After the verdict is presented and any stage.txt update is complete, close with a structured next-step prompt using AskUserQuestion.

Tailor the options to the gate that just ran:

For systems-design PASS:

Gate passed. What would you like to do next?
[A] Run /create-architecture — produce your master architecture blueprint and ADR work plan (recommended next step)
[B] Design more GDDs first — return here when all MVP systems are complete
[C] Stop here for this session

Note for systems-design PASS: /create-architecture is the required next step before writing any ADRs. It produces the master architecture document and a prioritized list of ADRs to write. Running /architecture-decision without this step means writing ADRs without a blueprint — skip it at your own risk.

For technical-setup PASS:

Gate passed. What would you like to do next?
[A] Start Pre-Production — begin prototyping the Vertical Slice
[B] Write more ADRs first — run /architecture-decision [next-system]
[C] Stop here for this session

For all other gates, offer the two most logical next steps for that phase plus "Stop here".

8. Follow-Up Actions

Based on the verdict, suggest specific next steps:

• No art bible? → /art-bible to create the visual identity specification
• Art bible exists but no asset specs? → /asset-spec system:[name] to generate per-asset visual specs and generation prompts from approved GDDs
• No game concept? → /brainstorm to create one
• No systems index? → /map-systems to decompose the concept into systems
• Missing design docs? → /reverse-document or delegate to game-designer
• Small design change needed? → /quick-design for changes under ~4 hours (bypasses full GDD pipeline)
• No UX specs? → /ux-design [screen name] to author specs, or /team-ui [feature] for full pipeline
• UX specs not reviewed? → /ux-review [file] or /ux-review all to validate
• No accessibility requirements doc? → Use AskUserQuestion to offer to create it now:
  • Prompt: "The gate requires design/accessibility-requirements.md. Shall I create it from the template?"
  • Options: `Create it now — I'll choose an accessibi