codetether-agent 4.0.0

# RLM Oracle System Implementation Summary

## Delivered Components

### 1. Grep Oracle ✅
**File**: `src/rlm/oracle/grep_oracle.rs`

- ✅ Compares model's grep-based FINAL() results against actual `grep -n` output
- ✅ Verifies claimed line numbers/matches against ground truth
- ✅ Supports common patterns: async functions, public functions, structs, enums, error handling
- ✅ Verification types: ExactMatch, UnorderedMatch, SubsetMatch, FalsePositives, FalseNegatives

**Key Functions**:
- `GrepOracle::new(source)` - Create oracle for source file
- `oracle.grep(pattern)` - Execute grep and get matches
- `oracle.verify(answer, query)` - Verify FINAL() answer
- `GrepOracle::infer_pattern(query)` - Infer grep pattern from natural language

### 2. Tree-sitter Oracle ✅
**File**: `src/rlm/oracle/tree_sitter_oracle.rs`

- ✅ Added `tree-sitter` and `tree-sitter-rust` dependencies to Cargo.toml
- ✅ AST-based verification for structural queries
- ✅ Supported queries:
  - Function signatures (name, args, return type)
  - Struct/enum definitions and fields
  - Impl blocks and trait implementations
  - Error handling patterns (Result, ?, match)
- ✅ Exposed as verification oracle
- ✅ Exposed as new DSL command: `ast_query("s-expr")`

**Key Functions**:
- `TreeSitterOracle::new(source)` - Create oracle
- `oracle.query(s_expr)` - Execute tree-sitter query
- `oracle.get_functions()` - Get all function signatures
- `oracle.get_structs()` - Get all struct definitions
- `oracle.get_enums()` - Get all enum definitions
- `oracle.count_error_patterns()` - Count error handling patterns

### 3. Trace Validator Pipeline ✅
**File**: `src/rlm/oracle/validator.rs`

- ✅ Orchestrates validation of RlmAnalysisResult
- ✅ Classifies query type (pattern-match vs structural vs semantic)
- ✅ Routes to appropriate oracle
- ✅ Marks traces as "golden", "unverified", or "failed"
- ✅ Outputs golden traces as JSONL for SFT training

**Key Functions**:
- `TraceValidator::new()` - Create validator
- `validator.validate(result, source, path)` - Validate single trace
- `validator.batch_validate(traces)` - Batch validation
- `stats.write_jsonl(path)` - Write golden traces to JSONL

### 4. Context Tracer ✅
**File**: `src/rlm/context_trace.rs`

- ✅ ContextTrace struct tracks token budget per RLM iteration
- ✅ Logs context events with byte/token counts:
  - SystemPrompt, GrepResult, LlmQueryResult
  - AssistantCode, ExecutionOutput, Final
  - ToolCall, ToolResult
- ✅ Circular buffer (max 1000 events) to bound memory
- ✅ Summary statistics and budget tracking

**Key Functions**:
- `ContextTrace::new(max_tokens)` - Create trace with budget
- `trace.log_event(event)` - Log event
- `trace.summary()` - Get statistics
- `trace.budget_used_percent()` - Check budget usage

## Integration Points

### RLM REPL (`src/rlm/repl.rs`)
- ✅ Added `ast_query("s-expr")` DSL command
- ✅ Integrated into `evaluate_expression()`
- ✅ Updated help text to include AST query
- ✅ Added to code extraction regex

### Tool Definitions (`src/rlm/tools.rs`)
- ✅ Added `rlm_ast_query` tool definition
- ✅ Added dispatcher for `rlm_ast_query` tool calls
- ✅ Updated test to include new tool

### Module Exports (`src/rlm/mod.rs`)
- ✅ Exported oracle types: GrepOracle, TreeSitterOracle, TraceValidator
- ✅ Exported validator types: OracleResult, ValidatedTrace, VerificationMethod
- ✅ Exported context trace types: ContextTrace, ContextEvent
- ✅ Exported classification types: QueryType, FinalAnswerFormat

### Dependencies (`Cargo.toml`)
- ✅ Added `tree-sitter = "0.24"`
- ✅ Added `tree-sitter-rust = "0.23"`

## Test Coverage

### Unit Tests
- ✅ Grep oracle: pattern inference, classification, verification
- ✅ Tree-sitter oracle: function/struct/enum extraction, error pattern counting
- ✅ Trace validator: validation routing, batch validation
- ✅ Context trace: token tracking, budget detection, filtering
- ✅ Final answer format: parsing different answer types

### Integration Tests
- ✅ `tests/test_oracle.rs` - Comprehensive integration tests

### Example
- ✅ `examples/oracle_demo.rs` - Usage demonstration

## Documentation

- ✅ `src/rlm/oracle/mod.rs` - Module-level documentation with usage examples
- ✅ `src/rlm/oracle/README.md` - Architecture diagram, API reference, performance notes
- ✅ `IMPLEMENTATION_SUMMARY.md` - This file

## Verification Strategy

| Query Type | Oracle | Verification Method |
|------------|--------|---------------------|
| Pattern-match | Grep | Compare line numbers and content |
| Structural | Tree-sitter | Compare AST-extracted structures |
| Semantic | None | Mark as unverified |

## Output Format

Golden traces are output as JSONL:
```json
{
  "query": "Find all async functions",
  "answer": "21:async fn process()",
  "iterations": 2,
  "subcalls": 0,
  "input_tokens": 150,
  "output_tokens": 80,
  "elapsed_ms": 500,
  "source_path": "src/main.rs",
  "verification_method": "GrepOracle",
  "timestamp": 1234567890,
  "trace_id": "uuid"
}
```

## Usage Example

```rust
use codetether_agent::rlm::oracle::{TraceValidator, OracleResult};

let validator = TraceValidator::new();
let result = validator.validate(&analysis_result, &source_code, Some("path.rs"));

match result {
    OracleResult::Golden(trace) => {
        // Verified! Write to training data
        writeln!(jsonl_file, "{}", serde_json::to_string(&trace)?)?;
    }
    OracleResult::Unverified { reason } => {
        // No deterministic oracle available
    }
    OracleResult::Failed { reason, .. } => {
        // Oracle disagrees - discard
    }
}
```

## Performance

- **Grep Oracle**: O(n) regex matching, typically <1ms for files <100KB
- **Tree-sitter Oracle**: O(n) parse once, O(m) query, typically <10ms
- **Context Trace**: O(1) event logging, 1000 event buffer

## Next Steps (Future Work)

1. **Self-consistency oracle**: For semantic queries, run 3x inference consensus (NOT implemented per spec)
2. **Execution-backed verification**: Security surface too large, deferred
3. **Multi-file queries**: Extend to cross-file analysis
4. **AST caching**: Incremental verification across runs
5. **Custom tree-sitter queries**: Allow users to define domain-specific queries

## Files Created/Modified

### Created
- `src/rlm/oracle/mod.rs`
- `src/rlm/oracle/grep_oracle.rs`
- `src/rlm/oracle/tree_sitter_oracle.rs`
- `src/rlm/oracle/validator.rs`
- `src/rlm/oracle/README.md`
- `src/rlm/context_trace.rs`
- `tests/test_oracle.rs`
- `examples/oracle_demo.rs`
- `IMPLEMENTATION_SUMMARY.md`

### Modified
- `src/rlm/mod.rs` - Added exports
- `src/rlm/repl.rs` - Added ast_query command
- `src/rlm/tools.rs` - Added ast_query tool
- `Cargo.toml` - Added tree-sitter dependencies