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.

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1. Parse Arguments

• 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 validate the NEXT phase transition

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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)

Quality Checks:

• Game concept has been reviewed (/design-review verdict not MAJOR REVISION NEEDED)
• Core loop is described and understood
• Target audience is identified

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Gate: Systems Design → Technical Setup

Required Artifacts:

• Systems index exists at design/gdd/systems-index.md with at least MVP systems enumerated
• At least 1 GDD in design/gdd/ (beyond game-concept.md and systems-index.md)

Quality Checks:

• GDD(s) pass design review (8 required sections present)
• System dependencies are mapped in the systems index
• MVP priority tier is defined

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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)
• At least 1 Architecture Decision Record in docs/architecture/
• Engine reference docs exist in docs/engine-reference/

Quality Checks:

• Architecture decisions cover core systems (rendering, input, state management)
• Technical preferences have naming conventions and performance budgets set

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Gate: Pre-Production → Production

Required Artifacts:

• At least 1 prototype in prototypes/ with a README
• First sprint plan exists in production/sprints/
• All MVP-tier GDDs from systems index are complete

Quality Checks:

• Prototype validates the core loop hypothesis
• Sprint plan references real work items from GDDs
• Vertical slice scope is defined

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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/
• At least 1 playtest report (or /playtest-report has been run)

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)

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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
• 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

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3. Run the Gate Check

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

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

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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.

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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

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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'?"

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7. Follow-Up Actions

Based on the verdict, suggest specific next steps:

• 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
• Missing ADRs? → /architecture-decision
• Tests failing? → delegate to lead-programmer or qa-tester
• No playtest data? → /playtest-report
• Performance unknown? → /perf-profile
• Not localized? → /localize
• Ready for release? → /launch-checklist

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Collaborative Protocol

This skill follows the collaborative design principle:

1. Scan first: Check all artifacts and quality gates
2. Ask about unknowns: Don't assume PASS for things you can't verify
3. Present findings: Show the full checklist with status
4. User decides: The verdict is a recommendation — the user makes the final call
5. Get approval: "May I write this gate check report to production/gate-checks/?"

Never block a user from advancing — the verdict is advisory. Document the risks
and let the user decide whether to proceed despite concerns.