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

1 files changed, 12 insertions, 0 deletions

diff --git a/src/main/ipc/handlers.ts b/src/main/ipc/handlers.ts
index e0863f3..4894e1d 100644
--- a/src/main/ipc/handlers.ts
+++ b/src/main/ipc/handlers.ts
@@ -4,6 +4,7 @@ import * as sessions from "../db/sessions";
 import * as claude from "../claude";
 import * as settingsDb from "../db/settings";
 import { createSessionBranch, ensureGitIgnore, ensureGitRepo, getCurrentBranch } from "../git";
+import { discoverMcpTools } from "../mcp";
 import type { UserPermissionMode } from "../claude/phases";
 import { getDefaultSystemPromptTemplate } from "../claude/phases";
 
@@ -199,4 +200,15 @@ export function registerIpcHandlers(mainWindow: BrowserWindow): void {
     });
     return result.canceled ? null : result.filePaths[0];
   });
+
+  // MCP
+  ipcMain.handle("mcp:discoverTools", async (_, config: {
+    type: "stdio" | "sse" | "http";
+    command?: string;
+    args?: string[];
+    env?: Record<string, string>;
+    url?: string;
+  }) => {
+    return discoverMcpTools(config);
+  });
 }