[MCP] Are local firestore emulators supported with the MCP server?

[arthurgousset]

Question

Are local firestore emulators supported with the MCP server?

Context

I'm referencing this post and this documentation:

I'm running a local firebase emulator and tried to query the local firestore DB using the MCP server. The MCP server is unable to query the local emulator.

I'm using Claude Code as an MCP client.

Steps to reproduce:

1. Authenticate with firebase

   # Authenticate
   firebase login --reauth

2. Add Firebase MCP server

   claude mcp add firebase --scope project \
     -- npx -y firebase-tools@latest experimental:mcp --dir "tools/firebase/" --only "firestore,ui,storage"

3. Confirm the MCP server is connected

   > /mcp 
   ╭───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
   │ Manage MCP servers                                                                                                                                                                                                                                                                                                                                                                                                                    │
   │                                                                                                                                                                                                                                                                                                                                                                                                                                       │
   │ ❯ 1. firebase  ✔ connected · Enter to view details                                                                                                                                                                                                                                                                                                                                                                                    │
   │                                                                                                                                                                                                                                                                                                                                                                                                                                       

4. Run local firestore emulator

5. Confirm emulator is running

   curl localhost:4400/emulators
   {
     "hub": {
       "listen": [
         {
           "address": "127.0.0.1",
           "family": "IPv4",
           "port": 4400
         },
         {
           "address": "::1",
           "family": "IPv6",
           "port": 4400
         }
       ],
       "name": "hub",
       "host": "127.0.0.1",
       "port": 4400
     },
     "ui": {
       "listen": [
         {
           "address": "127.0.0.1",
           "family": "IPv4",
           "port": 4000
         }
       ],
       "name": "ui",
       "host": "127.0.0.1",
       "port": 4000
     },
     "logging": {
       "listen": [
         {
           "address": "127.0.0.1",
           "family": "IPv4",
           "port": 4500
         }
       ],
       "name": "logging",
       "host": "127.0.0.1",
       "port": 4500
     },
     "firestore": {
       "listen": [
         {
           "address": "127.0.0.1",
           "family": "IPv4",
           "port": 8080
         }
       ],
       "name": "firestore",
       "host": "127.0.0.1",
       "port": 8080,
       "pid": 29416,
       "reservedPorts": [
         9150
       ],
       "webSocketHost": "127.0.0.1",
       "webSocketPort": 9150
     },
     "storage": {
       "listen": [
         {
           "address": "127.0.0.1",
           "family": "IPv4",
           "port": 9199
         }
       ],
       "name": "storage",
       "host": "127.0.0.1",
       "port": 9199
     }
   }                                                                                                                                                                                                                                                                                                                                                                                                                                       

6. Prompt Claude Code to query local firestore emulator

> try to access the firebase with the firebase mcp server

⏺ firebase - Query Firestore collection (MCP)(collection_path: "organizations", filters: [{"field":"__name__","op":"GREATER_THAN","compare_value":{"string_value":""}}], limit: 1, use_emulator: true)
  ⎿  Error: Cannot contact the Emulator Hub for project ...

⏺ firebase - List Firestore collections (MCP)(use_emulator: true)
  ⎿  Error: Cannot contact the Emulator Hub for project ...

The recurring error is Error: Cannot contact the Emulator Hub for project.

Claude Code was able to query the local firestore emulator via the Firestore REST API.