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:

Concept — Brainstorming, game concept document
Systems Design — Mapping systems, writing GDDs
Technical Setup — Engine config, architecture decisions
Pre-Production — Prototyping, vertical slice validation
Production — Feature development (Epic/Feature/Task tracking active)
Polish — Performance, playtesting, bug fixing
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

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

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

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

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

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

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)

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

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

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.

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

6. Update Stage on PASS

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

Write the new stage name to production/stage.txt (single line, no trailing newline)
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. 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

Collaborative Protocol

This skill follows the collaborative design principle:

Scan first: Check all artifacts and quality gates
Ask about unknowns: Don't assume PASS for things you can't verify
Present findings: Show the full checklist with status
User decides: The verdict is a recommendation — the user makes the final call
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.