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.github/prompts/workstream-execution.prompt.md

@@ -1373,7 +1373,380 @@ For everything else: **proceed with best effort and document assumptions**.
 
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-## 🎭 Your Role & Expertise
+## �️ Proven Patterns for Complex Tasks (FerrisScript Learnings)
+
+**When to Use These Patterns**: Multi-hour implementations (4+ hours), cross-crate changes, reflection/metadata systems, or features touching multiple pipeline stages.
+
+### Pattern 1: Checkpoint Methodology ✅
+
+**Source**: Phase 4.5 struct literal implementation (50% faster than Phase 4)
+
+**Problem**: Large features are hard to pause/resume, risky to implement all-at-once
+
+**Solution**: Break into 8 structured checkpoints with natural test/commit points
+
+**Checkpoint Structure**:
+
+1. **Checkpoint 1-2**: Foundation (AST nodes, basic parsing)
+2. **Checkpoint 3-4**: Core logic (type checking, validation)
+3. **Checkpoint 5-6**: Integration (runtime, conversions)
+4. **Checkpoint 7**: Error handling + recovery
+5. **Checkpoint 8**: Integration tests + documentation
+
+**Benefits**:
+
+- Natural pause points every 15-30 minutes
+- Easy to resume work (clear next checkpoint)
+- Early bug detection (test after each checkpoint)
+- Clear progress tracking (8/8 checkpoints = done)
+
+**Example Application** (Phase 4.5):
+
+- Checkpoint 1: AST StructLiteral node
+- Checkpoint 2: Parser basic syntax (`Type { }`)
+- Checkpoint 3: Parser field parsing (`field: value`)
+- Checkpoint 4: Type checker validate type name
+- Checkpoint 5: Type checker validate fields
+- Checkpoint 6: Runtime evaluate literal
+- Checkpoint 7: Error recovery (missing fields)
+- Checkpoint 8: Integration tests (all types)
+
+**How to Apply**:
+
+- For 4-6 hour feature: 8 checkpoints (~30 min each)
+- For 10+ hour feature: 3 sub-phases × 8 checkpoints each (24 total)
+- Test after each checkpoint (no commit until passing)
+- Document checkpoint completion in execution plan
+
+**Metrics**: 50% faster implementation, 3 bugs caught early (vs late-stage rework)
+
+---
+
+### Pattern 2: MVP + Robustness Split ✅
+
+**Source**: Phase 4.5 robustness testing (39 tests added after MVP)
+
+**Problem**: Trying to cover all edge cases during MVP slows progress
+
+**Solution**: Separate MVP implementation from robustness testing
+
+**MVP Phase** (Focus on happy path):
+
+- Basic functionality working
+- Core tests passing (feature works)
+- Integration with existing systems
+
+**Robustness Phase** (Focus on edge cases):
+
+- Missing/wrong/extra data
+- Type coercion and conversions
+- Error recovery and diagnostics
+- Integration examples
+- Performance edge cases
+
+**Benefits**:
+
+- MVP completes faster (don't get stuck on edge cases)
+- MVP proves feasibility early
+- Robustness testing validates production-readiness
+- Zero bugs found during robustness = good MVP quality
+
+**Example Application** (Phase 4.5):
+
+**MVP** (2.5 hours):
+
+- Struct literal syntax working
+- 31 tests re-enabled
+- 548 tests passing
+
+**Robustness** (3 hours):
+
+- 27 compiler edge case tests
+- 12 runtime execution tests
+- 5 integration examples
+- 587 tests passing (+39)
+
+**How to Apply**:
+
+- MVP first: Get feature working, basic tests passing
+- Commit MVP: "feat: [Feature] MVP complete"
+- Robustness next: Add edge case tests, examples
+- Commit robustness: "feat: [Feature] complete - robustness testing"
+
+**Metrics**: 0 bugs found during robustness testing (good MVP indicator)
+
+---
+
+### Pattern 3: Error Code Semantic Grouping ✅
+
+**Source**: Phase 4.5 struct literal errors (E701-E710 range)
+
+**Problem**: Large error code ranges (E100-E199) hard to navigate
+
+**Solution**: Allocate semantic ranges for feature families
+
+**Grouping Strategy**:
+
+- E70x: Struct literal errors (all types)
+- E801-E815: Export annotation errors (future)
+- Semantic > unique codes per type
+
+**Benefits**:
+
+- Easy to find related errors (all struct errors start with E7)
+- Can reuse codes across similar types (E701 = unknown field on ANY type)
+- Clear documentation patterns (E70x documentation section)
+
+**Example Application** (Phase 4.5):
+
+- E701-E703: Unknown field (Color, Rect2, Transform2D)
+- E704-E706: Missing field (reserved for future)
+- E707-E710: Type mismatch (reserved for future)
+- Reused E205 for Vector2 (existing error code)
+
+**How to Apply**:
+
+- Allocate 10-15 code range for feature
+- Group by category (parser, type checker, runtime)
+- Reuse codes across similar types
+- Document range in ERROR_CODES.md
+
+**Anti-Pattern**: E701 = Color field, E702 = Rect2 field → hard to remember
+
+---
+
+### Pattern 4: Integration Examples as Tests ✅
+
+**Source**: Phase 4.5 integration examples (5 .ferris files)
+
+**Problem**: Unit tests don't validate real-world usage patterns
+
+**Solution**: Create example files demonstrating practical patterns
+
+**Example File Structure**:
+
+```rust
+// examples/struct_literals_color.ferris
+# TEST: Color RGBA manipulation
+# CATEGORY: Type System
+# DESCRIPTION: Demonstrates Color struct literals with integer coercion
+# EXPECT: success
+
+// Real-world code here
+let red = Color { r: 1, g: 0, b: 0, a: 1 };  // Integer coercion
+```
+
+**Benefits**:
+
+- Examples serve as documentation
+- Examples validate real-world patterns
+- Examples can be used in test harness (metadata protocol)
+- Examples show best practices
+
+**Example Application** (Phase 4.5):
+
+- `struct_literals_color.ferris` - RGBA manipulation
+- `struct_literals_vector2.ferris` - Vector math
+- `struct_literals_rect2.ferris` - Boundaries
+- `struct_literals_transform2d.ferris` - Transformations
+- `struct_literals_functions.ferris` - Function patterns
+
+**How to Apply**:
+
+- Create 3-5 example files per feature
+- Include TEST metadata for harness integration
+- Demonstrate practical patterns (not just syntax)
+- Add to examples/ directory
+
+**Note**: Examples may not run through test harness immediately (Phase 5 work), but serve as reference
+
+---
+
+### Pattern 5: Sub-Phase Decomposition ✅
+
+**Source**: Phase 5 execution plan (3 sub-phases for @export)
+
+**Problem**: 20+ hour features too large for single-session implementation
+
+**Solution**: Decompose into independent sub-phases
+
+**Sub-Phase Structure**:
+
+1. **Sub-Phase 1: Parser & AST** (4-6 hours)
+   - Lexer tokens
+   - Parser grammar extension
+   - AST node definitions
+   - 8 checkpoints
+
+2. **Sub-Phase 2: Type Checker & Validation** (5-7 hours)
+   - Semantic validation
+   - Error code implementation
+   - Compatibility matrix
+   - 8 checkpoints
+
+3. **Sub-Phase 3: Runtime & Integration** (9-13 hours)
+   - Metadata storage
+   - Cross-crate integration
+   - Godot binding
+   - 8 checkpoints
+
+**Benefits**:
+
+- Each sub-phase can be implemented in separate session
+- Clear dependencies (must do Phase 1 before Phase 2)
+- Natural commit points (commit after each sub-phase)
+- Parallel work possible (if independent)
+
+**Example Application** (Phase 5):
+
+- Session 1: Parser + AST (4-6 hours)
+- Session 2: Type Checker (5-7 hours)
+- Session 3: Runtime + Godot (9-13 hours)
+- Total: 18-26 hours across 3 sessions
+
+**How to Apply**:
+
+- For 10+ hour feature: Split into 3 sub-phases
+- For 20+ hour feature: Split into 3-4 sub-phases
+- Each sub-phase has 8 checkpoints
+- Document sub-phase dependencies in execution plan
+
+**Metrics**: Phase 5 estimate = 23-31 hours → 3 sub-phases × 8 checkpoints = 24 total
+
+---
+
+### Pattern 6: Test-First Checkpoint Validation ✅
+
+**Source**: Phase 4.5 zero bugs during robustness testing
+
+**Problem**: Late-stage bugs require rework and context switching
+
+**Solution**: Write tests before implementation, validate at each checkpoint
+
+**Test-First Workflow**:
+
+1. Write test for checkpoint functionality
+2. Run test (expect failure)
+3. Implement checkpoint code
+4. Run test (expect pass)
+5. Move to next checkpoint
+
+**Benefits**:
+
+- Tests catch issues immediately
+- Clear success criteria (test passes = checkpoint done)
+- Zero bugs found during robustness = good quality
+- Tests serve as specification
+
+**Example Application** (Phase 4.5):
+
+- Checkpoint 3: Type checker validate type name
+  - Test: `test_struct_literal_wrong_type_name()` (write first)
+  - Implement: Type name validation (implement second)
+  - Result: Test passes → checkpoint complete
+
+**How to Apply**:
+
+- Write test before each checkpoint
+- Run test after implementation
+- Don't move to next checkpoint until tests pass
+- Document test count in checkpoint tracking
+
+**Metrics**: 0 bugs found during robustness testing = MVP quality validated
+
+---
+
+### Pattern 7: Execution Plan Template ✅
+
+**Source**: Phase 5 execution plan (comprehensive planning doc)
+
+**Problem**: Ad-hoc planning leads to scope creep and missed requirements
+
+**Solution**: Use structured execution plan template
+
+**Required Sections**:
+
+1. **Executive Summary** (goal, scope, why deferred if applicable)
+2. **Effort Estimation** (breakdown by category, total hours)
+3. **Sub-Phase Breakdown** (if 10+ hours)
+4. **Checkpoint Tracking** (24 total for complex features)
+5. **Testing Strategy** (MVP + robustness split)
+6. **Error Code Definitions** (allocated range)
+7. **File Modifications** (what will change)
+8. **Success Criteria** (functional + quality + integration)
+9. **Learnings from Previous Phases** (apply proven patterns)
+10. **Implementation Notes** (technical approach)
+
+**Benefits**:
+
+- Complete planning before implementation
+- Clear scope and requirements
+- Effort estimation for scheduling
+- Pattern reuse (apply Phase 4.5 learnings)
+
+**Example Application** (Phase 5):
+
+- 23-31 hour estimate (6 categories)
+- 3 sub-phases (Parser, Type Checker, Runtime)
+- 24 checkpoints (8 per sub-phase)
+- 51 total tests (30 MVP + 21 robustness)
+- Learnings from Phase 4.5 applied
+
+**How to Apply**:
+
+- Create execution plan before implementation
+- Use PHASE_X_EXECUTION_PLAN.md template
+- Document all decisions and assumptions
+- Update plan during implementation
+
+---
+
+### When to Use These Patterns
+
+**Use Checkpoint Methodology When**:
+
+- Feature will take 4+ hours
+- Multiple pipeline stages affected (parser + type checker + runtime)
+- Easy to get lost in implementation details
+
+**Use MVP + Robustness Split When**:
+
+- Feature has many edge cases
+- Want to prove feasibility quickly
+- Risk of scope creep
+
+**Use Sub-Phase Decomposition When**:
+
+- Feature will take 10+ hours
+- Can break into independent phases
+- Want to implement across multiple sessions
+
+**Use Test-First Validation When**:
+
+- Feature has clear specifications
+- Want to minimize bugs
+- Need confidence in implementation quality
+
+**Use All Patterns Together When**:
+
+- Complex feature (20+ hours)
+- Cross-crate changes
+- Reflection/metadata systems
+- High-risk implementation
+
+**Example**: Phase 5 @export uses ALL patterns:
+
+- ✅ Checkpoint methodology (24 checkpoints)
+- ✅ MVP + robustness split (30 MVP + 21 robustness)
+- ✅ Sub-phase decomposition (3 sub-phases)
+- ✅ Error code grouping (E801-E815)
+- ✅ Integration examples (3 files)
+- ✅ Test-first validation (51 tests)
+- ✅ Execution plan template (comprehensive doc)
+
+---
+
+## �🎭 Your Role & Expertise
 
 You are a **senior software engineer** with:
 

.gitignore

@@ -25,6 +25,7 @@ node_modules/
 
 # Temporary files (PR bodies, scripts)
 /temp/
+.github/PR_DESCRIPTION.md
 
 # OS
 Thumbs.db
@@ -53,3 +54,4 @@ tarpaulin-report.html
 
 # Godot UID files (auto-generated)
 *.gdextension.uid
+*.gd.uid