List top-level collections in Firestore
AI agents call list_collections to retrieve information from Firebase MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves metadata about available Firestore collections without modifying, deleting, or executing any operations. It is a straightforward inspection capability typical of Read category tools. Severity is low because listing collections exposes structure but not sensitive data directly, and the emulator environment further limits real-world impact.
From the tool's definition 'List top-level collections in Firestore' — a query/enumeration operation with no side effects; consistent with other Read tools on the server (list_documents, list_functions, list_subcollections).
Attacks that exploit this kind of access
List top-level collections in Firestore. It is categorised as a Read tool in the Firebase MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Firebase MCP Server MCP server in PolicyLayer and add a rule for list_collections: 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 Firebase MCP Server. Nothing to install.
list_collections is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the list_collections 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.
Set action: deny in the PolicyLayer policy for list_collections. 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.
list_collections is provided by the Firebase MCP Server MCP server (nigelthorne/firebase_mcp_server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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