# Quality Gates Agentic Quality Proxy Specification

## Executive Summary

The Quality Gates Agentic Quality Proxy is an MCP (Model Context Protocol) tool that intercepts code operations from AI coding agents (like Claude Code) and enforces quality standards before allowing code to be written or modified. This ensures that no low-quality code can ever enter the codebase when using AI agents.

## Problem Statement

AI coding agents can generate code of varying quality. Without enforcement, they may introduce:
- High complexity functions (>20 cognitive complexity)
- Self-admitted technical debt (SATD) comments
- Lint violations
- Incomplete implementations with stubs or TODOs
- Code that doesn't meet organizational quality standards

## Solution Architecture

### Core Concept

The proxy acts as a quality enforcement layer between AI agents and the filesystem:

```
AI Agent → MCP Request → Quality Proxy → Quality Gate Check → Accept/Reject → File System
```

### Key Components

1. **MCP Tool: `quality_proxy`**
   - Intercepts file write/edit operations
   - Validates code quality before allowing changes
   - Returns detailed feedback on quality violations
   - Optionally auto-refactors code to meet standards

2. **Quality Validation Pipeline**
   - Parse incoming code changes
   - Run quality-gate checks (complexity, SATD, lint)
   - Generate quality report
   - Apply auto-refactoring if enabled
   - Return result to agent

3. **Proxy Modes**
   - **Strict Mode**: Reject any code that fails quality checks
   - **Advisory Mode**: Warn but allow low-quality code
   - **Auto-Fix Mode**: Automatically refactor code to meet standards

## Detailed Design

### MCP Tool Interface

```json
{
  "name": "quality_proxy",
  "description": "Proxy code changes through quality gates before applying",
  "inputSchema": {
    "type": "object",
    "properties": {
      "operation": {
        "type": "string",
        "enum": ["write", "edit", "append"],
        "description": "Type of file operation"
      },
      "file_path": {
        "type": "string",
        "description": "Target file path"
      },
      "content": {
        "type": "string",
        "description": "New content for write/append operations"
      },
      "old_content": {
        "type": "string",
        "description": "Content to replace for edit operations"
      },
      "new_content": {
        "type": "string",
        "description": "Replacement content for edit operations"
      },
      "mode": {
        "type": "string",
        "enum": ["strict", "advisory", "auto-fix"],
        "default": "strict",
        "description": "Proxy enforcement mode"
      },
      "quality_config": {
        "type": "object",
        "properties": {
          "max_complexity": {"type": "integer", "default": 20},
          "allow_satd": {"type": "boolean", "default": false},
          "require_docs": {"type": "boolean", "default": true},
          "auto_format": {"type": "boolean", "default": true}
        }
      }
    },
    "required": ["operation", "file_path"]
  }
}
```

### Response Format

```json
{
  "status": "accepted|rejected|modified",
  "quality_report": {
    "passed": boolean,
    "metrics": {
      "max_complexity": number,
      "satd_count": number,
      "lint_violations": number,
      "coverage_percentage": number
    },
    "violations": [
      {
        "type": "complexity|satd|lint|docs",
        "severity": "error|warning",
        "location": "file:line:column",
        "message": "Description of violation",
        "suggestion": "How to fix"
      }
    ]
  },
  "final_content": "The actual content that was/would be written",
  "refactoring_applied": boolean,
  "refactoring_plan": [...]
}
```

### Implementation Modules

#### 1. `server/src/services/quality_proxy.rs`
Core proxy service that orchestrates quality validation:
- Receives proxy requests
- Parses and analyzes code
- Runs quality gates
- Applies refactoring if needed
- Returns structured response

#### 2. `server/src/mcp/handlers/quality_proxy.rs`
MCP handler that exposes the proxy as an MCP tool:
- Handles MCP tool invocations
- Validates input parameters
- Calls proxy service
- Formats MCP responses

#### 3. `server/src/models/proxy.rs`
Data models for proxy operations:
- `ProxyRequest`: Input parameters
- `ProxyResponse`: Result with quality report
- `ProxyMode`: Enforcement modes
- `QualityConfig`: Customizable thresholds

### Quality Enforcement Rules

1. **Complexity Check**
   - Maximum cognitive complexity: 20
   - Split complex functions automatically in auto-fix mode
   - Provide refactoring suggestions in advisory mode

2. **SATD Detection**
   - Zero tolerance for TODO, FIXME, HACK comments
   - Detect incomplete implementations
   - Require full functionality

3. **Lint Compliance**
   - Run clippy with strict settings
   - Auto-format with rustfmt
   - Enforce naming conventions

4. **Documentation Requirements**
   - Public functions must have doc comments
   - Complex logic must be explained
   - Examples required for public APIs

### Integration with Existing Systems

1. **Quality Gate Service Integration**
   - Reuse existing `QualityGateService`
   - Leverage complexity analysis
   - Use SATD detection engine

2. **Refactor Service Integration**
   - Use `RefactorService` for auto-fix mode
   - Apply AI-driven refactoring plans
   - Maintain code semantics

3. **MCP Server Integration**
   - Register as new MCP tool
   - Support streaming for large files
   - Handle concurrent requests

## Usage Examples

### Example 1: Strict Mode (Default)
```typescript
// AI Agent attempts to write low-quality code
const request = {
  tool: "quality_proxy",
  arguments: {
    operation: "write",
    file_path: "src/utils.rs",
    content: `
      fn process_data(data: Vec<Data>) -> Result<Output> {
        // TODO: implement this properly
        unimplemented!("not yet implemented")
      }
    `,
    mode: "strict"
  }
};

// Response: REJECTED
{
  status: "rejected",
  quality_report: {
    passed: false,
    violations: [
      {
        type: "satd",
        severity: "error",
        message: "TODO comment detected",
        location: "src/utils.rs:3:11"
      },
      {
        type: "incomplete",
        severity: "error",
        message: "Stub implementation with unimplemented!()",
        location: "src/utils.rs:4:9"
      }
    ]
  }
}
```

### Example 2: Auto-Fix Mode
```typescript
// AI Agent writes complex code
const request = {
  tool: "quality_proxy",
  arguments: {
    operation: "write",
    file_path: "src/analyzer.rs",
    content: complexFunction, // 50+ complexity
    mode: "auto-fix"
  }
};

// Response: MODIFIED
{
  status: "modified",
  quality_report: {
    passed: true,
    metrics: {
      max_complexity: 18  // After refactoring
    }
  },
  refactoring_applied: true,
  final_content: refactoredCode
}
```

### Example 3: Advisory Mode
```typescript
// AI Agent writes code with minor issues
const request = {
  tool: "quality_proxy",
  arguments: {
    operation: "edit",
    file_path: "src/lib.rs",
    old_content: "fn helper() { ... }",
    new_content: "pub fn helper() { ... }",  // Missing docs
    mode: "advisory"
  }
};

// Response: ACCEPTED with warnings
{
  status: "accepted",
  quality_report: {
    passed: false,
    violations: [
      {
        type: "docs",
        severity: "warning",
        message: "Public function missing documentation",
        suggestion: "Add /// doc comment"
      }
    ]
  },
  final_content: "pub fn helper() { ... }"
}
```

## Testing Strategy

### Unit Tests
- Test each proxy mode independently
- Validate quality check integration
- Test error handling and edge cases
- Verify refactoring application

### Property Tests
- Generate random code with varying complexity
- Ensure proxy always enforces thresholds
- Test that auto-fix maintains semantics
- Verify no quality regressions

### Doctests
- Document all public APIs with examples
- Show typical usage patterns
- Demonstrate error conditions
- Include configuration examples

### Integration Tests
- Full MCP request/response cycle
- Multi-file operation handling
- Concurrent request processing
- Performance under load

### Example Programs
- `examples/proxy_demo.rs`: Interactive proxy demonstration
- `examples/proxy_benchmarks.rs`: Performance testing
- `examples/proxy_integration.rs`: Integration with Claude Code

## Performance Considerations

1. **Caching**
   - Cache AST parsing results
   - Reuse quality gate computations
   - Store refactoring plans

2. **Streaming**
   - Support streaming for large files
   - Progressive quality checking
   - Incremental response updates

3. **Concurrency**
   - Handle multiple proxy requests in parallel
   - Thread-safe quality validation
   - Async MCP handlers

## Security Considerations

1. **Input Validation**
   - Sanitize file paths
   - Validate content size limits
   - Prevent path traversal attacks

2. **Resource Limits**
   - Maximum file size: 10MB
   - Timeout for analysis: 30 seconds
   - Memory limits for AST parsing

3. **Audit Logging**
   - Log all proxy operations
   - Track quality violations
   - Record refactoring actions

## Migration Path

### Phase 1: Core Implementation
- Implement proxy service
- Add MCP handler
- Basic quality validation

### Phase 2: Enhanced Features
- Auto-refactoring support
- Streaming for large files
- Performance optimizations

### Phase 3: Advanced Integration
- IDE plugin support
- Web UI for configuration
- Analytics dashboard

## Success Metrics

1. **Quality Metrics**
   - 100% of AI-generated code meets quality standards
   - Zero SATD comments in proxied code
   - All functions ≤20 complexity

2. **Performance Metrics**
   - <100ms latency for small files
   - <1s for files up to 1000 lines
   - Support 100+ concurrent requests

3. **Adoption Metrics**
   - Used by all AI coding sessions
   - Positive developer feedback
   - Reduced code review time

## Configuration

### Environment Variables
```bash
PMAT_PROXY_MODE=strict|advisory|auto-fix
PMAT_PROXY_MAX_COMPLEXITY=20
PMAT_PROXY_ALLOW_SATD=false
PMAT_PROXY_REQUIRE_DOCS=true
PMAT_PROXY_AUTO_FORMAT=true
```

### Config File (`~/.pmat/proxy.toml`)
```toml
[proxy]
default_mode = "strict"
enable_caching = true
max_file_size_mb = 10

[quality]
max_complexity = 20
allow_satd = false
require_docs = true
auto_format = true

[performance]
enable_streaming = true
max_concurrent_requests = 100
analysis_timeout_seconds = 30
```

## Appendix: Implementation Checklist

- [ ] Create `server/src/services/quality_proxy.rs`
- [ ] Create `server/src/models/proxy.rs`
- [ ] Create `server/src/mcp/handlers/quality_proxy.rs`
- [ ] Update `server/src/mcp/handlers/mod.rs` to include proxy
- [ ] Add proxy handler to MCP server initialization
- [ ] Implement unit tests in `quality_proxy.rs`
- [ ] Create property tests in `tests/quality_proxy_properties.rs`
- [ ] Add doctests to all public functions
- [ ] Create `examples/proxy_demo.rs`
- [ ] Update README with proxy documentation
- [ ] Run quality-gate on all new code
- [ ] Create integration tests
- [ ] Performance benchmarks
- [ ] Security audit
- [ ] Release notes