# Story Documentation Pattern

Complete guide to documenting implementation work in story files.

---

## Purpose

Story files in DevForgeAI serve as the **single source of truth** for each unit of work, containing:
1. **Requirements** (user story, acceptance criteria, Definition of Done)
2. **Implementation** (what was done, how, and verification) ← THIS DOCUMENT
3. **Workflow** (state transitions, QA results, deployment)

**Without implementation documentation:**
- Story file is incomplete (requirements only)
- No audit trail for QA validation
- Knowledge lost (implementation decisions)
- Violates spec-driven development principle

---

## When to Update Story Files

**MANDATORY:** Update story file with Implementation Notes BEFORE final git commit in every development phase.

**Timing:**
- After implementation complete
- After tests passing
- Before `git commit`
- Story file must be included in commit

---

## Implementation Notes Template

```markdown
## Implementation Notes

**Developer:** DevForgeAI AI Agent (or human developer name)
**Implemented:** 2025-11-01 14:30:00
**Commit:** abc1234def5678 (update after commit)

### Definition of Done Status

[Copy each DoD item from story, mark completion]

- [x] Unit tests written and passing - Completed: Created 5 unit tests in tests/unit/calculator/, all passing
- [x] Integration tests added - Completed: Created 2 integration tests for API endpoints
- [x] Code follows coding-standards.md - Completed: Applied rustfmt, followed naming conventions
- [ ] Performance benchmarks created - Not completed: Deferred to STORY-045 (performance optimization epic)

### Key Implementation Decisions

[Document 2-5 significant technical decisions]

- **Decision 1:** Used anyhow::Result instead of custom error type
  - **Rationale:** tech-stack.md specifies anyhow for error handling, simpler for CLI tool
  - **Alternatives considered:** thiserror (rejected - overkill for simple errors), custom enum (rejected - boilerplate)

- **Decision 2:** Placed parser logic in src/parser/mod.rs
  - **Rationale:** source-tree.md specifies src/parser/ for parsing logic, separates concerns

- **Decision 3:** Used lazy_static for compiled queries
  - **Rationale:** Queries compiled once at startup (performance), matches coding-standards.md lazy initialization pattern

### Files Created/Modified

[Organize by layer from source-tree.md]

**Layer: CLI Interface**
- `src/cli/mod.rs` - CLI argument parsing with clap derive macros
- `src/cli/commands.rs` - Subcommand implementations (analyze, query, grammar)

**Layer: Core Library**
- `src/parser/mod.rs` - Tree-sitter AST parser
- `src/query/engine.rs` - Pattern matching engine

**Tests:**
- `tests/unit/parser_tests.rs` - Unit tests for AST parsing (8 tests)
- `tests/integration/cli_tests.rs` - Integration tests for CLI (5 tests)

### Test Results

- **Unit tests:** 13 passing / 13 total
- **Integration tests:** 5 passing / 5 total
- **E2E tests:** 0 (not applicable for this story)
- **Coverage:** 87% (target: 95% business logic, 85% application, 80% infrastructure)
- **All tests passing:** YES

**Coverage by layer:**
- Business logic (parser, query): 92%
- Application (CLI): 78%
- Infrastructure (fs, error): 85%

### Acceptance Criteria Verification

[For each Given/When/Then, document verification method]

**AC-1: Given valid Rust file, When parsed, Then AST generated**
- [x] **Verified:** `cargo test parser_tests::test_parse_rust_file` passes
- **Method:** Unit test validates Rust parser generates correct AST nodes

**AC-2: Given god-objects pattern, When query executes, Then violations detected**
- [x] **Verified:** `cargo test integration_tests::test_god_objects_detection` passes
- **Method:** Integration test with 600-line fixture file triggers violation

**AC-3: Given invalid query file, When loaded, Then error message shown**
- [x] **Verified:** `cargo test query_tests::test_invalid_query_handling` passes
- **Method:** Unit test validates anyhow error propagation

### Notes

**Blockers encountered:**
- None

**Workarounds applied:**
- None

**Technical debt introduced:**
- None - All code follows tech-stack.md, architecture-constraints.md

**Future improvements:**
- Consider adding query caching for repeated patterns (defer to STORY-089 - Performance optimization)
- Add colored output for better UX (defer to STORY-034 - CLI UX enhancements)
```

---

## Examples

### Example 1: Setup Story (STORY-001)

**Story Type:** Infrastructure setup (no feature code)

```markdown
## Implementation Notes

**Developer:** DevForgeAI AI Agent
**Implemented:** 2025-11-01 10:15:00
**Commit:** 0109459d20e543560c4782a04f31071a5ec6709e

### Definition of Done Status

- [x] Cargo.toml created with all dependencies - Completed: Created with 20 production dependencies matching dependencies.md
- [x] Directory structure matches source-tree.md - Completed: Created src/, tests/, benches/, docs/, queries/, grammars/
- [x] Project compiles without errors - Completed: `cargo check` passed (37.66s, 218 packages locked)
- [x] Basic test infrastructure works - Completed: `cargo test --lib` passes (1 test passing)
- [x] Formatting applied - Completed: `cargo fmt` applied Rust formatting

### Key Implementation Decisions

- **Decision 1:** Used Cargo workspace structure (single crate for v1.0)
  - **Rationale:** source-tree.md specifies workspace pattern, simpler for MVP
  - **Alternatives:** Multi-crate workspace (deferred to v1.1 when adding Python lib)

- **Decision 2:** Bundled 6 tree-sitter grammars in dependencies
  - **Rationale:** dependencies.md specifies tree-sitter-javascript, typescript, python, c-sharp, go, rust
  - **Note:** Grammars will be embedded at build time per tech-stack.md build process

### Files Created/Modified

**Layer: Project Root**
- `Cargo.toml` - Project manifest with dependencies, metadata, features
- `Cargo.lock` - Locked dependency versions for reproducible builds
- `src/main.rs` - CLI entry point (minimal hello world)
- `src/lib.rs` - Library root with basic test

**Layer: Infrastructure**
- `test-fixtures/.gitkeep` - Preserves test fixtures directory

**Directories Created:**
- `src/`, `tests/`, `benches/`, `docs/`, `queries/`, `grammars/`, `test-fixtures/`

### Test Results

- **Unit tests:** 1 passing / 1 total (lib.rs::it_works)
- **Integration tests:** 0 (none yet)
- **E2E tests:** 0 (none yet)
- **Coverage:** N/A (setup story, no business logic yet)
- **All tests passing:** YES

**Build verification:**
- `cargo check`: PASSED (37.66s)
- `cargo build`: PASSED (31.72s, debug binary created)
- `cargo test --lib`: PASSED (1 test, 0 failures)
- `cargo fmt`: APPLIED (no warnings)

### Acceptance Criteria Verification

**AC-1: Cargo workspace initialized**
- [x] **Verified:** Cargo.toml exists, contains workspace configuration
- **Method:** File exists, `cargo check` compiles successfully

**AC-2: All dependencies from dependencies.md configured**
- [x] **Verified:** All 20 dependencies present in Cargo.toml with correct versions
- **Method:** Manual comparison against dependencies.md, Cargo.lock generated

**AC-3: Directory structure matches source-tree.md**
- [x] **Verified:** All required directories created (src, tests, benches, docs, queries, grammars, test-fixtures)
- **Method:** Visual inspection, matches source-tree.md specification

**AC-4: Project builds without errors**
- [x] **Verified:** `cargo build` completed successfully, binary created
- **Method:** cargo build output shows "Finished `dev` profile [unoptimized + debuginfo] target(s)"

### Notes

**Technical context:**
- This is the foundation story for Codelens v1.0
- Establishes Rust 1.75+ baseline
- All subsequent stories depend on this setup

**Next story:** STORY-002 will implement tree-sitter FFI integration building on this foundation
```

---

### Example 2: Feature Story with All DoD Completed

**Story Type:** Feature implementation (business logic)

```markdown
## Implementation Notes

**Developer:** DevForgeAI AI Agent
**Implemented:** 2025-11-05 15:45:00
**Commit:** def5678abc1234

### Definition of Done Status

- [x] Red phase: Failing tests written - Completed: Created 8 failing unit tests for pattern matching
- [x] Green phase: Tests passing - Completed: Implemented PatternMatcher, all 8 tests pass
- [x] Refactor phase: Code improved - Completed: Extracted PatternBuilder, reduced complexity from 12 to 6
- [x] Integration tests added - Completed: Created 3 integration tests for end-to-end pattern execution
- [x] Coverage ≥95% for business logic - Completed: 97% coverage for src/query/engine.rs
- [x] No anti-patterns detected - Completed: context-validator passed, zero violations
- [x] Documentation updated - Completed: Added rustdoc comments for all public APIs

### Key Implementation Decisions

- **Decision 1:** Used tree-sitter::Query directly instead of wrapper
  - **Rationale:** tech-stack.md specifies tree-sitter 0.20, no wrapper needed per anti-patterns.md (avoid abstraction layers)
  - **Performance:** Direct API call, no overhead

- **Decision 2:** Pre-compiled queries with lazy_static
  - **Rationale:** coding-standards.md recommends lazy initialization for expensive operations, queries compiled once
  - **Measurement:** Benchmark shows 10x speedup vs. parsing query on each execution

- **Decision 3:** Used rayon for parallel query execution
  - **Rationale:** dependencies.md includes rayon, architecture-constraints.md allows parallelism in query layer
  - **Performance:** 4 queries execute in parallel on 4-core CPU, 75% time reduction

### Files Created/Modified

**Layer: Core Library - Query Module**
- `src/query/engine.rs` - Pattern matching engine with parallel execution (320 lines)
- `src/query/compiler.rs` - Query compilation and validation (180 lines)
- `src/query/mod.rs` - Public API for query module (45 lines)

**Layer: Pattern Library**
- `src/patterns/anti_patterns.rs` - Anti-pattern query definitions (210 lines)
- `src/patterns/mod.rs` - Pattern registry and loader (95 lines)

**Tests:**
- `tests/unit/query_engine_tests.rs` - Unit tests for pattern matching (8 tests, 250 lines)
- `tests/integration/pattern_execution_tests.rs` - Integration tests (3 tests, 120 lines)
- `test-fixtures/god_object_600_lines.rs` - Test fixture for god-objects pattern

### Test Results

- **Unit tests:** 8 passing / 8 total
- **Integration tests:** 3 passing / 3 total
- **E2E tests:** 0 (not applicable)
- **Coverage:** 94% overall
- **All tests passing:** YES

**Coverage by layer:**
- Business logic (query engine): 97%
- Application (pattern registry): 89%
- Infrastructure (fs helpers): 86%

**Coverage meets thresholds:** YES (95%/85%/80%)

### Acceptance Criteria Verification

**AC-1: Given AST and pattern, When query executes, Then violations returned**
- [x] **Verified:** `cargo test query_engine_tests::test_execute_query` passes
- **Method:** Unit test with mock AST, validates violation detection

**AC-2: Given 4 patterns, When executed in parallel, Then all violations found**
- [x] **Verified:** `cargo test integration_tests::test_parallel_pattern_execution` passes
- **Method:** Integration test runs 4 patterns on same AST, validates all results returned

**AC-3: Given invalid query, When compiled, Then error returned**
- [x] **Verified:** `cargo test query_compiler_tests::test_invalid_query_compilation` passes
- **Method:** Unit test validates anyhow::Error propagation with helpful message

**AC-4: Given complex pattern (nested predicates), When executed, Then correct matches found**
- [x] **Verified:** `cargo test pattern_tests::test_layer_boundaries_detection` passes
- **Method:** Integration test with fixture containing actual layer violation

### Notes

**Performance benchmarks:**
- Single pattern execution: 250ms for 10K line file
- 4 patterns sequential: 1,000ms
- 4 patterns parallel (rayon): 275ms (75% improvement)

**Technical debt:**
- None introduced

**Future optimizations:**
- Query result caching (defer to STORY-089)
- Incremental re-parsing (defer to STORY-112 - service mode)
```

---

### Example 3: Feature Story with Deferred Items

**Story Type:** Feature with scope reduction

```markdown
## Implementation Notes

**Developer:** DevForgeAI AI Agent
**Implemented:** 2025-11-08 09:20:00
**Commit:** 456789abc123def

### Definition of Done Status

- [x] Core grammar loading implemented - Completed: GrammarLoader struct with load_grammar() method
- [x] Bundled grammars embedded - Completed: 5 grammars embedded via include_dir, 25MB binary
- [x] Grammar auto-detection works - Completed: Detects language from file extension
- [ ] Grammar version management - Not completed: Deferred to STORY-067 (grammar updates)
- [ ] Grammar compatibility validation - Not completed: Out of scope (determined unnecessary for v1.0)

**Deferred items explanation:**
- **STORY-067 (Grammar updates):** Version management requires persistent cache and update mechanism, complexity too high for v1.0 MVP
- **Compatibility validation:** Testing shows tree-sitter grammars are backward compatible, validation adds complexity without value for v1.0

### Key Implementation Decisions

- **Decision 1:** Used include_dir to embed grammars at compile time
  - **Rationale:** dependencies.md includes include_dir, allows offline operation
  - **Trade-off:** Larger binary (25MB) but zero runtime dependencies

- **Decision 2:** Deferred grammar version management to v1.1
  - **Rationale:** Complexity assessment showed +8 story points, timeline risk for v1.0
  - **Mitigation:** Documented in STORY-067 for v1.1 epic

### Files Created/Modified

**Layer: Grammar Module**
- `src/grammars/loader.rs` - Grammar loading with bundled + cache support (280 lines)
- `src/grammars/detector.rs` - Language detection from file extensions (150 lines)
- `src/grammars/mod.rs` - Public API (60 lines)

**Layer: Build System**
- `build.rs` - Compile-time grammar embedding (120 lines)

**Tests:**
- `tests/unit/grammar_loader_tests.rs` - 6 unit tests for loader
- `tests/integration/grammar_detection_tests.rs` - 4 integration tests

### Test Results

- **Unit tests:** 6 passing / 6 total
- **Integration tests:** 4 passing / 4 total
- **Coverage:** 91%
- **All tests passing:** YES

**Coverage:**
- Grammar loader: 94%
- Language detector: 89%
- Build script: N/A (build-time code)

### Acceptance Criteria Verification

**AC-1: Bundled grammars work offline**
- [x] **Verified:** Integration test with no internet connection, grammar loads successfully
- **Method:** tests/integration/offline_grammar_test.rs

**AC-2: Auto-install downloads missing grammars**
- [x] **Verified:** Integration test mocks network, validates download URL construction
- **Method:** tests/integration/auto_install_test.rs (mocked)

**AC-3: Language detected from file extension**
- [x] **Verified:** Unit tests for .rs→Rust, .py→Python, .js→JavaScript
- **Method:** tests/unit/language_detection_tests.rs (6 test cases)

**AC-4: Grammar versions compatible**
- [ ] **Not verified:** Deferred - out of scope for v1.0

### Notes

**Scope reduction:**
- Removed grammar version management (deferred to STORY-067)
- Removed compatibility validation (determined unnecessary)
- User approved via AskUserQuestion on 2025-11-07

**Technical debt:**
- None - Deferred items are documented in backlog, not shortcuts

**Blockers:**
- Initial blocker: Grammar embedding exceeded binary size target (35MB)
- Resolution: Removed debug symbols, optimized grammar sizes, achieved 25MB
```

---

## Best Practices

### Level of Detail

**Too Vague (❌):**
```markdown
### Files Created
- src/parser.rs - Parser logic
```

**Too Verbose (❌):**
```markdown
### Files Created
- src/parser/mod.rs - This file contains the parser module which uses tree-sitter to parse source code into Abstract Syntax Trees. It handles language detection, grammar loading, incremental parsing, and error recovery. The module exposes a public Parser struct with methods for...
[200 words]
```

**Just Right (✅):**
```markdown
### Files Created
- src/parser/mod.rs` - Tree-sitter AST parser with incremental parsing support (280 lines)
```

### Definition of Done Status

**Insufficient (❌):**
```markdown
- [x] Tests written
```

**Complete (✅):**
```markdown
- [x] Unit tests written and passing - Completed: Created 8 unit tests in tests/unit/parser/, all passing with 94% coverage
```

### Acceptance Criteria Verification

**Incomplete (❌):**
```markdown
- [x] Scenario 1: Verified
```

**Complete (✅):**
```markdown
- [x] **Verified:** `cargo test integration_tests::test_scenario_1` passes - validates input X produces output Y
- **Method:** Integration test with real fixtures, asserts expected violations found
```

---

## Integration with QA

### QA Skill Will Validate

**spec-driven-qa Deep Validation checks:**
1. Implementation Notes section exists
2. All DoD items have status ([x] or [ ] with reason)
3. Test results documented (passing counts, coverage %)
4. Acceptance criteria verification present
5. Files listed
6. Key decisions documented (for audit trail)

**If validation fails:**
- QA Status: FAILED
- Violation: "Story documentation incomplete"
- Severity: HIGH
- Action: Developer must update story before QA approval

---

## Common Mistakes

### Mistake 1: Skipping Implementation Notes

**Problem:** Update status to "Dev Complete" without documentation
**Impact:** Story incomplete, QA cannot validate, knowledge lost
**Prevention:** Phase 08 Step b. is MANDATORY before commit

### Mistake 2: Placeholder TODOs

**Problem:**
```markdown
### Key Decisions
- TODO: Document decisions
```

**Impact:** Story appears documented but contains no information
**Prevention:** Generate actual content, not placeholders

### Mistake 3: Not Documenting Deferred Items

**Problem:**
```markdown
### Definition of Done
- [x] Item 1
- [x] Item 2
[Item 3 missing - was it done or not?]
```

**Impact:** Unclear if Item 3 was forgotten or intentionally deferred
**Prevention:** Mark ALL DoD items with [x] or [ ] and reason

---

## Template Checklist

Before committing, verify Implementation Notes include:

- [ ] Developer and timestamp
- [ ] Definition of Done items with status
- [ ] Key implementation decisions (2-5 decisions)
- [ ] Files created/modified with purposes
- [ ] Test results with counts and coverage
- [ ] Acceptance criteria verification with methods
- [ ] Notes section (even if "None" for blockers/debt)
- [ ] All sections filled (no "TODO" placeholders)
- [ ] Story file staged in git commit

---

**This pattern ensures stories are complete records of requirements + implementation + verification, fulfilling DevForgeAI's spec-driven development principle.**
