From 044d628a47f063bcbbd9adba7860542156a0c66e Mon Sep 17 00:00:00 2001
From: Clawd <ai@clawd.bot>
Date: Sun, 1 Mar 2026 10:15:14 -0800
Subject: feat(mcp): add tool discovery and per-tool permissions

- Add MCP protocol client for tool discovery (initialize + tools/list)
- Show discovered tools in settings UI with enable/disable checkboxes
- Build explicit allowedTools list from enabled MCP tools
- Remove bypassPermissions hack - now uses proper tool allowlisting
- Format: mcp__servername__toolname for SDK allowedTools
---
 src/main/mcp.ts | 151 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 151 insertions(+)
 create mode 100644 src/main/mcp.ts

(limited to 'src/main/mcp.ts')

diff --git a/src/main/mcp.ts b/src/main/mcp.ts
new file mode 100644
index 0000000..cfd3d26
--- /dev/null
+++ b/src/main/mcp.ts
@@ -0,0 +1,151 @@
+import { spawn, type ChildProcess } from "node:child_process";
+import { randomUUID } from "node:crypto";
+
+interface McpTool {
+  name: string;
+  description?: string;
+}
+
+interface McpServerConfig {
+  type: "stdio" | "sse" | "http";
+  command?: string;
+  args?: string[];
+  env?: Record<string, string>;
+  url?: string;
+}
+
+interface JsonRpcRequest {
+  jsonrpc: "2.0";
+  id: string | number;
+  method: string;
+  params?: Record<string, unknown>;
+}
+
+interface JsonRpcResponse {
+  jsonrpc: "2.0";
+  id: string | number;
+  result?: unknown;
+  error?: { code: number; message: string };
+}
+
+/**
+ * Connect to an MCP server and discover its available tools.
+ * Only supports stdio transport for now.
+ */
+export async function discoverMcpTools(
+  config: McpServerConfig
+): Promise<{ tools: McpTool[]; error?: string }> {
+  if (config.type !== "stdio") {
+    return { tools: [], error: "Only stdio transport is supported for tool discovery" };
+  }
+
+  if (!config.command) {
+    return { tools: [], error: "Command is required for stdio transport" };
+  }
+
+  let process: ChildProcess | null = null;
+  let buffer = "";
+
+  try {
+    // Spawn the MCP server process
+    process = spawn(config.command, config.args || [], {
+      env: { ...globalThis.process.env, ...config.env },
+      stdio: ["pipe", "pipe", "pipe"],
+    });
+
+    if (!process.stdin || !process.stdout) {
+      return { tools: [], error: "Failed to create process streams" };
+    }
+
+    const sendRequest = (request: JsonRpcRequest): void => {
+      const json = JSON.stringify(request);
+      process!.stdin!.write(json + "\n");
+    };
+
+    const waitForResponse = (id: string | number, timeoutMs = 10000): Promise<JsonRpcResponse> => {
+      return new Promise((resolve, reject) => {
+        const timeout = setTimeout(() => {
+          reject(new Error("Timeout waiting for MCP response"));
+        }, timeoutMs);
+
+        const onData = (chunk: Buffer) => {
+          buffer += chunk.toString();
+          
+          // Try to parse complete JSON-RPC messages (newline-delimited)
+          const lines = buffer.split("\n");
+          buffer = lines.pop() || ""; // Keep incomplete line in buffer
+
+          for (const line of lines) {
+            if (!line.trim()) continue;
+            try {
+              const response = JSON.parse(line) as JsonRpcResponse;
+              if (response.id === id) {
+                clearTimeout(timeout);
+                process!.stdout!.off("data", onData);
+                resolve(response);
+                return;
+              }
+            } catch {
+              // Not valid JSON, skip
+            }
+          }
+        };
+
+        process!.stdout!.on("data", onData);
+      });
+    };
+
+    // Step 1: Initialize
+    const initId = randomUUID();
+    sendRequest({
+      jsonrpc: "2.0",
+      id: initId,
+      method: "initialize",
+      params: {
+        protocolVersion: "2024-11-05",
+        capabilities: {},
+        clientInfo: { name: "claude-flow", version: "1.0.0" },
+      },
+    });
+
+    const initResponse = await waitForResponse(initId);
+    if (initResponse.error) {
+      return { tools: [], error: `Initialize failed: ${initResponse.error.message}` };
+    }
+
+    // Send initialized notification (no response expected)
+    process.stdin.write(JSON.stringify({
+      jsonrpc: "2.0",
+      method: "notifications/initialized",
+    }) + "\n");
+
+    // Step 2: List tools
+    const toolsId = randomUUID();
+    sendRequest({
+      jsonrpc: "2.0",
+      id: toolsId,
+      method: "tools/list",
+      params: {},
+    });
+
+    const toolsResponse = await waitForResponse(toolsId);
+    if (toolsResponse.error) {
+      return { tools: [], error: `tools/list failed: ${toolsResponse.error.message}` };
+    }
+
+    const result = toolsResponse.result as { tools?: Array<{ name: string; description?: string }> };
+    const tools: McpTool[] = (result.tools || []).map((t) => ({
+      name: t.name,
+      description: t.description,
+    }));
+
+    return { tools };
+  } catch (err) {
+    return { tools: [], error: String(err) };
+  } finally {
+    // Clean up
+    if (process) {
+      process.kill();
+    }
+  }
+}
-- 
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