oxify-mcp 0.1.0

Model Context Protocol (MCP) server implementation for OxiFY
Documentation
# oxify-mcp - Development TODO

**Codename:** The Ecosystem (MCP Integration)
**Status:** ✅ Phase 1-3 Completed, Phase 4-5 Remaining
**Next Phase:** Authentication & Security

---

## Phase 1: MCP Protocol Implementation ✅ COMPLETED

**Goal:** Implement Model Context Protocol (MCP) client and server.

### Current Status ✅
- [x] Basic types (McpRequest, McpResponse, McpError, ToolSchema)
- [x] McpClient trait definition
- [x] DefaultMcpClient implementation
- [x] McpServer trait definition
- [x] Server registry (McpRegistry) for managing multiple servers

### MCP Client ✅
- [x] **Stdio Transport:**
  - [x] Launch MCP server as subprocess
  - [x] JSON-RPC over stdio
  - [x] Process lifecycle management

- [x] **HTTP Transport:**
  - [x] Connect to remote MCP server
  - [x] JSON-RPC over HTTP
  - [ ] Authentication support (planned for Phase 4)

### MCP Server ✅
- [x] **McpServer trait:**
  - [x] Tool discovery endpoint (list_tools)
  - [x] Tool invocation endpoint (call_tool)
  - [x] Schema generation with JSON Schema
  - [x] Result formatting as JSON

---

## Phase 2: Tool Discovery & Execution ✅ COMPLETED

**Goal:** Discover and execute MCP tools.

### Tool Discovery ✅
- [x] **List Available Tools:**
  - [x] Query MCP server for tools (list_tools)
  - [x] Parse tool schemas (ToolSchema type)
  - [x] Cache tool metadata (McpRegistry)

### Tool Execution ✅
- [x] **Invoke MCP Tools:**
  - [x] Parameter validation (via JSON Schema)
  - [x] Invoke tool on MCP server (call_tool)
  - [x] Parse and return results (JSON values)
  - [x] Error handling (McpError)

### Integration with oxify-engine ✅ COMPLETE
- [x] **Tool Node Execution:**
  - [x] Execute MCP tools from workflow (via MCP_EXECUTOR global)
  - [x] Pass parameters from execution context (McpConfig.parameters)
  - [x] Store tool results (ExecutionResult returned to engine)
  - [x] Local server registration (register_local_server)
  - [x] HTTP MCP servers (automatic initialization)
  - [x] HTTP fallback for backward compatibility
  - [x] 11 comprehensive tests in mcp_executor.rs

---

## Phase 3: Multiple MCP Servers ✅ COMPLETED

**Goal:** Manage multiple MCP servers.

### Server Registry ✅
- [x] **Register MCP Servers:**
  - [x] Server ID and connection info (McpRegistry)
  - [x] Dynamic server registration/unregistration
  - [x] Tool discovery across all servers
  - [x] Registry statistics
  - [ ] Authentication credentials (planned for Phase 4)
  - [ ] Server health checks (future enhancement)

### Load Balancing ✅ COMPLETE (NEW)
- [x] **Distribute Tool Calls:**
  - [x] Round-robin across servers
  - [x] Least connections strategy
  - [x] Random selection
  - [x] Weighted round-robin based on server weights
  - [x] Server affinity (sticky sessions via groups)
  - [x] Failover to backup servers (invoke_tool_with_failover)
  - [x] Server health tracking (Healthy/Degraded/Unhealthy)
  - [x] Server metrics (request_count, error_count, avg_response_time_ms)
  - [x] Tag-based server selection

---

## Phase 4: Authentication & Security ✅ COMPLETE

**Goal:** Secure MCP communication.

### Authentication ✅ COMPLETE (Updated)
- [x] **API Key Authentication:**
  - [x] Pass API keys to MCP servers via headers
  - [x] ApiKeyAuth with optional prefix support
  - [x] Configurable header name
  - [x] 14 comprehensive unit tests

- [x] **Basic Authentication:**
  - [x] HTTP Basic auth (username:password)
  - [x] Base64 encoding
  - [x] Authorization header support

- [x] **Bearer Token Authentication:**
  - [x] OAuth2-style bearer tokens
  - [x] JWT token support
  - [x] Authorization header support

- [x] **Custom Header Authentication:**
  - [x] Arbitrary custom headers
  - [x] Multiple headers support

- [x] **Credential Management:**
  - [x] CredentialStore for multiple servers
  - [x] AuthConfig wrapper with scopes
  - [x] AuthenticatedHttpTransport

- [x] **OAuth2 Authentication:** ✅ COMPLETED
  - [x] OAuth2 flow for MCP servers (client credentials, authorization code, refresh token)
  - [x] Automatic token refresh with expiry tracking
  - [x] PKCE support for authorization code flow
  - [x] Multiple grant types (ClientCredentials, AuthorizationCode, RefreshToken)
  - [x] Scope management
  - [x] Comprehensive unit tests (11 OAuth2 tests)

### Sandboxing (Future)
- [ ] **Isolate MCP Tool Execution:**
  - [ ] Resource limits (CPU, memory, time)
  - [ ] Network restrictions
  - [ ] File system restrictions

---

## Phase 5: Built-in MCP Servers ✅ COMPLETE

**Goal:** Provide useful built-in MCP servers.

### Workflow Server ✅ NEW
- [x] **Workflow Execution:**
  - [x] WorkflowServer for exposing workflows as MCP tools
  - [x] Auto-generate tool schemas from workflow metadata
  - [x] Template variable extraction for input schema
  - [x] Custom input schemas per workflow
  - [x] Custom descriptions override
  - [x] Pluggable executor function (WorkflowExecutor type)
  - [x] Thread-safe workflow registration (Arc<RwLock>)
  - [x] Configurable tool naming prefix
  - [x] 11 comprehensive tests

### Filesystem Server ✅
- [x] **File Operations:**
  - [x] Read file (fs_read)
  - [x] Write file (fs_write)
  - [x] List directory (fs_list)
  - [x] Delete file/directory (fs_delete)
  - [x] Check existence (fs_exists)
  - [x] Security: Path sandboxing and validation
  - [x] Comprehensive tests

### Web Server ✅
- [x] **Web Operations:**
  - [x] HTTP GET (http_get)
  - [x] HTTP POST (http_post)
  - [x] Web scraping (web_scrape) - basic implementation
  - [ ] Take screenshot (web_screenshot) - requires headless browser

### Git Server ✅
- [x] **Git Operations:**
  - [x] Status (git_status)
  - [x] Clone (git_clone)
  - [x] Add (git_add)
  - [x] Commit (git_commit)
  - [x] Push (git_push)
  - [x] Pull (git_pull)
  - [x] Log (git_log)
  - [x] Diff (git_diff)
  - [x] Branch listing (git_branch)
  - [x] Checkout (git_checkout)

### Shell Server ✅
- [x] **Shell Operations:**
  - [x] Execute command (shell_exec)
  - [x] Find command (shell_which)
  - [x] Command whitelist for security
  - [x] Environment variable support
  - [x] Working directory support
  - [x] Comprehensive tests

### Database Server ✅
- [x] **Fully Implemented:**
  - [x] Database query (db_query) - SELECT queries with JSON results
  - [x] Execute command (db_execute) - INSERT/UPDATE/DELETE with rows affected
  - [x] Transaction support (db_transaction) - Atomic multi-statement execution
  - [x] Table description (db_describe) - Schema information
  - [x] List tables (db_tables) - Schema exploration
  - [x] Read-only mode support
  - [x] Type conversion for PostgreSQL types (bool, int, float, text, uuid, timestamp, json, bytea)
  - [x] Connection pooling via sqlx
  - [x] Comprehensive unit tests (7 tests)

---

## Phase 6: Testing & Quality ✅ MOSTLY COMPLETED

**Goal:** Comprehensive testing.

### Current Status ✅
- [x] 86 unit tests implemented and passing (updated)
- [x] Zero warnings in compilation
- [x] Comprehensive test coverage for all major components

### Completed
- [x] **Unit Tests:**
  - [x] Test registry (7 tests)
  - [x] Test FilesystemServer (6 tests)
  - [x] Test ShellServer (7 tests)
  - [x] Test WebServer (8 tests)
  - [x] Test GitServer (13 tests)
  - [x] Test transport layer (5 tests)
  - [x] Security tests (path traversal, command whitelist, path validation)

### Remaining
- [ ] **Unit Tests:**
  - [x] Test DatabaseServer (7 tests with database feature)

- [ ] **Integration Tests (Future):**
  - [ ] Test with real external MCP servers
  - [ ] Test stdio transport with subprocess
  - [ ] Test HTTP transport with remote server
  - **Note:** Current unit tests provide comprehensive coverage (75+ tests)

---

## Documentation ✅ COMPLETED

### Current Status ✅
- [x] Comprehensive inline documentation
- [x] Three working examples (basic_usage.rs, transport_example.rs, multi_server_orchestration.rs)
- [x] Comprehensive README.md with full documentation

### Completed ✅
- [x] **Code Documentation:**
  - [x] All public APIs documented
  - [x] Examples in doc comments

- [x] **Usage Examples:**
  - [x] basic_usage.rs - demonstrates all built-in servers
  - [x] transport_example.rs - demonstrates transport layer
  - [x] multi_server_orchestration.rs - advanced registry usage

- [x] **README:**
  - [x] MCP overview
  - [x] Quick start guide
  - [x] API documentation with code examples
  - [x] All built-in servers documented (Filesystem, Shell, Git, Web, Database, Workflow)
  - [x] Authentication guide (API key, Basic, Bearer, Custom)
  - [x] Load balancing guide (strategies, failover, tags)
  - [x] Custom server development guide
  - [x] Integration examples
  - [x] Testing guide
  - [x] Contributing guidelines

---

## Integration

### oxify-engine Integration ✅ COMPLETE
- [x] **Tool Node Execution:**
  - [x] Discover MCP tools (list_tools, list_all_local_tools)
  - [x] Execute MCP tools from workflows (execute_tool)
  - [x] Handle tool errors
  - [x] Register local MCP servers (FilesystemServer, WorkflowServer, etc.)
  - [x] Priority: Local servers → HTTP MCP → HTTP fallback
  - [x] 9 comprehensive tests

### oxify-api Integration ✅ COMPLETE
- [x] **MCP Management API:**
  - [x] List registered MCP servers (GET /api/v1/mcp/servers)
  - [x] List available tools (POST /api/v1/mcp/tools)
  - [x] Test tool execution (POST /api/v1/mcp/tools/invoke)
  - [x] Registry statistics (GET /api/v1/mcp/stats)
  - [x] Server registration/unregistration endpoints
  - [x] 10 comprehensive unit tests in mcp_handlers.rs

---

## License

MIT OR Apache-2.0

---

## Summary of Progress

### ✅ Completed (Phases 1-3, 5)
1. **Core MCP Implementation**
   - Full MCP protocol support (client, server, transport)
   - DefaultMcpClient with HTTP and Stdio transports
   - McpServer trait for building custom servers
   - Comprehensive error handling

2. **Server Registry**
   - McpRegistry for managing multiple servers
   - Dynamic server registration/unregistration
   - Tool discovery across all servers
   - Registry statistics and search

3. **Built-in Servers**
   - FilesystemServer (5 tools) ✅
   - ShellServer (2 tools) ✅
   - GitServer (10 tools) ✅
   - WebServer (4 tools, 1 pending) ⚠️
   - DatabaseServer (5 tools - PostgreSQL) ✅
   - WorkflowServer (dynamic tools) ✅

4. **Testing**
   - 86 unit tests passing
   - Zero compilation warnings
   - Comprehensive test coverage:
     - Registry (7 tests)
     - FilesystemServer (6 tests)
     - ShellServer (7 tests)
     - WebServer (8 tests)
     - GitServer (13 tests)
     - DatabaseServer (7 tests)
     - WorkflowServer (11 tests)
     - Transport layer (5 tests)
     - Authentication (14 tests)
     - OAuth2 (11 tests)

5. **Examples**
   - basic_usage.rs - Complete walkthrough of all built-in servers
   - transport_example.rs - Transport layer demonstration
   - multi_server_orchestration.rs - Advanced registry usage
   - api_integration.rs - Integration with oxify-api MCP endpoints

6. **Security Enhancements**
   - Response size limits (10MB default)
   - Request/response validation
   - Path traversal prevention
   - Command whitelist enforcement
   - Timeout handling (30s default for HTTP)

7. **Authentication (NEW)****
   - API Key, Basic, Bearer, Custom Header auth methods
   - AuthenticatedHttpTransport for secure connections
   - CredentialStore for multi-server credentials
   - 14 comprehensive unit tests

8. **Load Balancing (NEW)****
   - Round-robin, Least Connections, Random, Weighted strategies
   - Server health tracking (Healthy/Degraded/Unhealthy)
   - Server metrics (request/error counts, response times)
   - Failover support with invoke_tool_with_failover
   - Group-based and tag-based server selection

### 🚧 In Progress / Remaining
1. **Phase 6: Integration Testing (Future)**
   - Integration tests with external MCP servers
   - End-to-end workflow tests

2. **Remaining Features (Future)**
   - Advanced resource limits and sandboxing
   - WebSocket transport support

---

**Last Updated:** 2026-01-08
**Document Version:** 4.3
**Status:** Production Ready - All Core Features Complete + oxify-api Integration
**Test Status:** ✅ 86 tests passing, 0 warnings
**Code Coverage:** Registry, All Servers (Filesystem, Shell, Web, Git, Database, Workflow), Transport Layer, Auth (including OAuth2), oxify-api Integration (10 tests)