From 569e2b24a491e9097232972551643b9163a46b53 Mon Sep 17 00:00:00 2001
From: Joe Hanley <joehanley@google.com>
Date: Fri, 25 Sep 2026 23:23:12 +0000
Subject: [PATCH 1/2] fix(mcp): start project detection in start() instead of
 constructor (b/566322255)

---
 src/mcp/index.spec.ts | 24 ++++++++++++++++++++++++
 src/mcp/index.ts      |  5 +++--
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/src/mcp/index.spec.ts b/src/mcp/index.spec.ts
index e935bafc55e..c1d4c7bfc57 100644
--- a/src/mcp/index.spec.ts
+++ b/src/mcp/index.spec.ts
@@ -120,3 +120,27 @@ describe("FirebaseMcpServer.mcpCallTool", () => {
     expect(toolFn.firstCall.args[0]).to.deep.equal({ foo: "bar" });
   });
 });
+
+describe("FirebaseMcpServer project detection", () => {
+  afterEach(() => {
+    sinon.restore();
+  });
+
+  it("does not start project detection when constructed", () => {
+    const detectStub = sinon.stub(FirebaseMcpServer.prototype, "detectProjectSetup").resolves();
+
+    new FirebaseMcpServer({});
+
+    expect(detectStub.called).to.be.false;
+  });
+
+  it("starts project detection when started", async () => {
+    const detectStub = sinon.stub(FirebaseMcpServer.prototype, "detectProjectSetup").resolves();
+    const server = new FirebaseMcpServer({});
+    sinon.stub(server.server, "connect").resolves();
+
+    await server.start();
+
+    expect(detectStub.calledOnce).to.be.true;
+  });
+});
diff --git a/src/mcp/index.ts b/src/mcp/index.ts
index 936f61e3a1e..230751725f1 100644
--- a/src/mcp/index.ts
+++ b/src/mcp/index.ts
@@ -156,8 +156,6 @@ export class FirebaseMcpServer {
       this.currentLogLevel = params.level;
       return {};
     });
-
-    void this.detectProjectSetup();
   }
 
   /** Wait until initialization has finished. */
@@ -508,6 +506,9 @@ export class FirebaseMcpServer {
   }
 
   async start(options?: { useSSE?: boolean; port?: number }): Promise<void> {
+    // Background detection starts when the server is started, not when it is constructed, so constructing a server (as unit tests do) has no side effects.
+    void this.detectProjectSetup();
+
     if (options?.useSSE) {
       const app = express();
 

From 294160eb49619f3ada175392ddfaf0f40912f2d7 Mon Sep 17 00:00:00 2001
From: Joe Hanley <joehanley@google.com>
Date: Sat, 3 Oct 2026 01:22:10 +0000
Subject: [PATCH 2/2] fix(mcp): catch unhandled rejection on background project
 detection

---
 src/mcp/index.spec.ts | 18 ++++++++++++++++++
 src/mcp/index.ts      |  4 +++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/mcp/index.spec.ts b/src/mcp/index.spec.ts
index c1d4c7bfc57..df4606b0246 100644
--- a/src/mcp/index.spec.ts
+++ b/src/mcp/index.spec.ts
@@ -143,4 +143,22 @@ describe("FirebaseMcpServer project detection", () => {
 
     expect(detectStub.calledOnce).to.be.true;
   });
+
+  it("handles rejection in background project detection without unhandled rejection", async () => {
+    sinon
+      .stub(FirebaseMcpServer.prototype, "detectProjectSetup")
+      .rejects(new Error("detection failed"));
+    const server = new FirebaseMcpServer({});
+    sinon.stub(server.server, "connect").resolves();
+    const debugStub = sinon.stub();
+    sinon.stub(server, "logger").get(() => ({
+      debug: debugStub,
+    }));
+
+    await server.start();
+    await new Promise((resolve) => setTimeout(resolve, 10));
+
+    expect(debugStub.calledOnce).to.be.true;
+    expect(debugStub.firstCall.args[0]).to.include("Background project detection failed");
+  });
 });
diff --git a/src/mcp/index.ts b/src/mcp/index.ts
index 230751725f1..03e67026822 100644
--- a/src/mcp/index.ts
+++ b/src/mcp/index.ts
@@ -507,7 +507,9 @@ export class FirebaseMcpServer {
 
   async start(options?: { useSSE?: boolean; port?: number }): Promise<void> {
     // Background detection starts when the server is started, not when it is constructed, so constructing a server (as unit tests do) has no side effects.
-    void this.detectProjectSetup();
+    void this.detectProjectSetup().catch((err: unknown) => {
+      this.logger.debug(`[mcp] Background project detection failed: ${err}`);
+    });
 
     if (options?.useSSE) {
       const app = express();