create_document · Firestore MCP Server MCP: Risk & Policy

WHAT IT DOES

What create_document does on Firestore MCP Server

AI agents use create_document to create or update resources in Firestore MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Firestore MCP Server environment.

WHY IT NEEDS A POLICY

Why create_document needs a policy

The tool creates new documents in a Firestore collection, which is a reversible write operation. It does not execute arbitrary code, delete data, or move money. Write operations carry medium severity because an AI agent could create unwanted documents, duplicate data, or pollute the database, but the effects can be undone via deletion. Confidence is high because the function name and description are explicit.

From the tool's definition Tool name: 'create_document' with description 'Create a new document in a collection'. The Firestore MCP server description states it enables 'full CRUD operations' including creation. This tool creates new data in the database.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_document Rate-limited

create_document stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "create_document": {
      "limits": [
        {
          "counter": "create_document_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Firestore MCP Server, so you can run agents against it safely.

FAQ

Questions about create_document

What does the create_document tool do? +

Create a new document in a collection. It is categorised as a Write tool in the Firestore MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_document? +

Register the Firestore MCP Server MCP server in PolicyLayer and add a rule for create_document: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Firestore MCP Server. Nothing to install.

What risk level is create_document? +

create_document is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit create_document? +

Yes. Add a rate_limit block to the create_document rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block create_document completely? +

Set action: deny in the PolicyLayer policy for create_document. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides create_document? +

create_document is provided by the Firestore MCP Server MCP server (yudai-uk/firestore-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.