Query entities with a simple equality filter on any field
AI agents call datastore_filter to retrieve information from MCP Datastore Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves or queries data based on an equality filter condition. It has no side effects, does not modify, delete, or execute external operations. It is a straightforward read operation consistent with the broader server's query/retrieval mandate.
From the tool's definition Tool description states it 'Query entities with a simple equality filter on any field' — a read-only query operation.
Attacks that exploit this kind of access
Query entities with a simple equality filter on any field. It is categorised as a Read tool in the MCP Datastore Server MCP Server, which means it retrieves data without modifying state.
Register the MCP Datastore Server MCP server in PolicyLayer and add a rule for datastore_filter: 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 MCP Datastore Server. Nothing to install.
datastore_filter 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 datastore_filter 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 datastore_filter. 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.
datastore_filter is provided by the MCP Datastore Server MCP server (johnreitano/daisy). 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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