fix(mcp): Make tool schemas more Gemini-compatible. (firebase#8637)

Author: mbleigh

scripts/mcp-tests/gemini-smoke-test.ts

@@ -0,0 +1,70 @@
+import { Client } from "@modelcontextprotocol/sdk/client/index.js";
+import { StdioClientTransport } from "@modelcontextprotocol/sdk/client/stdio.js";
+
+if (!process.env.GEMINI_API_KEY) {
+  console.error("Must set GEMINI_API_KEY to run this smoke test.");
+  process.exit(1);
+}
+
+const client = new Client({
+  name: "firebase-mcp-smoke-tester",
+  version: "0.0.1",
+});
+
+await client.connect(
+  new StdioClientTransport({
+    command: "../../lib/bin/firebase.js",
+    args: [
+      "experimental:mcp",
+      "--only",
+      "firestore,dataconnect,messaging,remoteconfig,crashlytics,auth,storage",
+    ],
+  }),
+);
+
+const { tools } = await client.listTools();
+
+const geminiTools = tools.map((tool) => {
+  return {
+    name: tool.name,
+    description: tool.description,
+    parameters: tool.inputSchema,
+  };
+});
+
+const response = await fetch(
+  `https://generativelanguage.googleapis.com/v1beta/models/gemini-2.0-flash:generateContent?key=${process.env.GEMINI_API_KEY}`,
+  {
+    method: "POST",
+    headers: {
+      "content-type": "application/json",
+    },
+    body: JSON.stringify({
+      toolConfig: {
+        functionCallingConfig: { mode: "auto" },
+      },
+      tools: [{ functionDeclarations: geminiTools }],
+      contents: [
+        {
+          parts: [{ text: "Call the firebase_list_apps tool." }],
+        },
+      ],
+    }),
+  },
+);
+
+if (response.status === 200) {
+  console.dir(await response.json(), { depth: null });
+
+  console.log("✅ Passed smoke test!");
+  process.exit(0);
+} else {
+  const rtext = await response.text();
+  try {
+    console.dir(JSON.parse(rtext), { depth: null });
+  } catch (e) {
+    console.log(rtext);
+  }
+  console.error("ERROR: Got non-200 response from smoke test.");
+  process.exit(1);
+}