Search the knowledge graph for entities. Filter by type, text content, source/provenance,
AI agents call query_knowledge to retrieve information from CodeGraph 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 from a knowledge graph with no indication of side effects. It filters and searches existing entities without creating, modifying, deleting, or executing operations. It falls clearly into the Read category with low severity since it only allows information retrieval from what appears to be an internal knowledge base.
From the tool's definition Tool name is 'query_knowledge' and description states 'Search the knowledge graph for entities' with filtering capabilities. The verb 'search' and 'query' indicate data retrieval without modification.
Documented attack patterns abuse exactly the kind of access query_knowledge gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and CodeGraph, and nothing reaches the server without passing your rules. This is the rule we recommend for query_knowledge:
{
"version": "1",
"default": "deny",
"tools": {
"query_knowledge": {}
}
}query_knowledge is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Search the knowledge graph for entities. Filter by type, text content, source/provenance,. It is categorised as a Read tool in the CodeGraph MCP Server, which means it retrieves data without modifying state.
Register the CodeGraph MCP server in PolicyLayer and add a rule for query_knowledge: 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 CodeGraph. Nothing to install.
query_knowledge 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_knowledge 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_knowledge. 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_knowledge is provided by the CodeGraph MCP server (phoenixrr2113/codebase-graph). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from CodeGraph, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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18 CodeGraph tools catalogued and risk-classified — across an index of 43,000+ MCP servers.