MCP Server

Status: stable | Score: 100% | Last Tested: 2026-07-18

Overview

Xavier implements an HTTP-first integration server with optional Model Context Protocol (MCP) support. This protocol exposes 16 specialized tools allowing external LLMs or agents to query memory, retrieve documents, execute code searches, route code-graph queries, and manage contexts efficiently.

Architecture & Design

The MCP Server conforms strictly to the Model Context Protocol specifications. It enforces camelCase serialization (e.g., mapping input_schema to inputSchema, mime_type to mimeType, and is_error to isError) to maintain schema compliance with official clients. To prevent test flakiness, tests handle both snake_case and camelCase serialized keys robustly.

Implementation Paths

• src/server/http/ (REST endpoints and HTTP routing)
• src/server/mcp/ (MCP server protocol, tools, and schema handlers)
• src/cli/server.rs (server CLI launching and capability configuration)

Sub-features

• mcp-tools-core: Implements definitions and execution handlers for 16 core tools (including mem_search, memory_context, codebase symbols, plus codegraph_route and codegraph_gods since wave-24).
• mcp-progressive: Features the Progressive Disclosure pattern for token optimization (relying on structured, lightweight mem_search followed by a targeted memory_context fetch).
• mcp-auth: Token-based authentication integration for secure endpoint access.

Test References

• src/server/mcp/tests.rs unit and integration tests asserting camelCase keys.
• Integration tests validating the progressive disclosure search pipeline.

Known Issues & Notes

• Grok MCP doctor: Handshake is successful, but there is some protocol drift on tools/list causing 18 unit tests to fail under the full suite when strictly checking strict protocol boundaries.
• Progressive disclosure reduces token overhead by ~90% for active agents.

Functional MCP Integration Example

Add Xavier as an MCP server inside your Claude Desktop configuration file:

Configuration (claude_desktop_config.json):

{
  "mcpServers": {
    "xavier": {
      "command": "xavier",
      "args": ["mcp"],
      "env": {
        "XAVIER_TOKEN": "your-secret-token"
      }
    }
  }
}

Verify available MCP tools using the standard MCP protocol inspector or client handshakes:

npx @modelcontextprotocol/inspector xavier mcp