List subcollections of a document
AI agents call list_subcollections to retrieve information from Firebase Live MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and retrieves metadata about Firestore document structure (subcollection names). It performs no writes, deletions, or external operations. The blast radius of misuse is minimal — an agent could enumerate subcollections but cannot modify or delete data. Classified as Read with low severity.
From the tool's definition Tool name is 'list_subcollections' and description states 'List subcollections of a document' — a pure retrieval operation with no modification or side effects.
Attacks that exploit this kind of access
List subcollections of a document. It is categorised as a Read tool in the Firebase Live MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Firebase Live MCP Server MCP server in PolicyLayer and add a rule for list_subcollections: 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 Live MCP Server. Nothing to install.
list_subcollections 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_subcollections 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_subcollections. 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_subcollections is provided by the Firebase Live MCP Server MCP server (nigelthorne/firebase_live_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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