Query a collection with filters
AI agents call query_collection 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 and filters data from Firestore collections without modifying, deleting, or executing operations. It is a Read operation. Severity is medium rather than low because unfiltered or overly broad queries in a multi-tenant or sensitive database context could expose large volumes of data to unauthorized access, creating a moderate blast radius if an AI agent misuses filter parameters.
From the tool's definition Tool name 'query_collection' and description 'Query a collection with filters' indicate data retrieval operations. Server description confirms 'querying of Firestore data' and 'navigate collections, retrieve documents'.
Attacks that exploit this kind of access
Query a collection with filters. 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 query_collection: 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.
query_collection 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 query_collection 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 query_collection. 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.
query_collection 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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