Delve MCP

Instructions

Implementation Reference

• src/server.ts:301-318 (schema)

  Schema definition for the 'replay' tool, specifying input parameters tracePath (required) and onProcess (optional).
  { name: "replay", description: "Replay an rr trace", inputSchema: { type: "object", properties: { tracePath: { type: "string", description: "Path to the rr trace directory" }, onProcess: { type: "number", description: "Optional PID to pass to rr" } }, required: ["tracePath"] } },
• src/server.ts:406-407 (registration)

  Tool call dispatch logic that routes 'replay' tool invocations to the handleDebugCommands function.
  if (["debug", "attach", "exec", "test", "core", "dap", "replay", "trace"].includes(name)) { return handleDebugCommands(name, args);
• src/handlers/debug.ts:6-93 (handler)

  Core handler function for debug tools including 'replay'. Dispatches to startDebugSession based on tool name (specific case for 'replay' follows the pattern of other tools).
  export async function handleDebugCommands(name: string, args: any) { switch (name) { case "debug": { const pkg = (args?.package as string) || "."; const buildFlags = args?.buildFlags as string | undefined; const cmdArgs: string[] = []; if (buildFlags) { cmdArgs.push("--build-flags", buildFlags); } const session = await startDebugSession("debug", pkg, cmdArgs); return { content: [{ type: "text", text: `Started debug session ${session.id} for package ${pkg}` }] }; } case "attach": { const pid = Number(args?.pid); if (!pid) { throw new Error("Process ID is required"); } const session = await startDebugSession("attach", pid.toString()); return { content: [{ type: "text", text: `Attached to process ${pid} with session ${session.id}` }] }; } case "exec": { const binary = String(args?.binary); const cmdArgs = (args?.args as string[]) || []; const session = await startDebugSession("exec", binary, cmdArgs); return { content: [{ type: "text", text: `Started debug session ${session.id} for binary ${binary}` }] }; } case "test": { const pkg = (args?.package as string) || "."; const testFlags = (args?.testFlags as string[]) || []; const session = await startDebugSession("test", pkg, ["--", ...testFlags]); return { content: [{ type: "text", text: `Started test debug session ${session.id} for package ${pkg}` }] }; } case "core": { const { executable, corePath } = args; const session = await startDebugSession("core", executable, [corePath]); return { content: [{ type: "text", text: `Started core dump analysis session ${session.id} for ${executable} with core ${corePath}` }] }; } case "dap": { const { clientAddr } = args; const cmdArgs = clientAddr ? ["--client-addr", clientAddr] : []; const session = await startDebugSession("dap", "", cmdArgs); return { content: [{ type: "text", text: `Started DAP server session ${session.id}${clientAddr ? ` connecting to ${clientAddr}` : ''}` }] }; } default: throw new Error("Unknown debug command"); }
• src/session.ts:35-64 (helper)

  Starts the Delve process for 'replay' type by spawning 'dlv replay --headless :port tracePath [args]', enabling the core tool execution.
  export async function startDebugSession(type: string, target: string, args: string[] = []): Promise<DebugSession> { const port = await getAvailablePort(); const id = Math.random().toString(36).substring(7); const dlvArgs = [ type, "--headless", `--listen=:${port}`, "--accept-multiclient", "--api-version=2", target, ...args ]; const process = spawn("dlv", dlvArgs, { stdio: ["pipe", "pipe", "pipe"] }); const session: DebugSession = { id, type, target, process, port, breakpoints: new Map() }; sessions.set(id, session); return session; }
• src/types.ts:18-19 (schema)

  Type definition for DebugSession including 'replay' as a valid session type.
  type: string; // 'debug' | 'attach' | 'exec' | 'test' | 'core' | 'replay' | 'trace' | 'dap' target: string;