Run a raw Cypher query against the code graph. Use with caution - read-only queries only.
AI agents invoke query_graph to trigger actions in CodeGraph. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
The tool executes raw Cypher queries, which is an Execute-level action. Although the description advises read-only use, there is no technical enforcement preventing write or destructive Cypher (e.g., MERGE, DELETE, DETACH DELETE). Because arbitrary query execution is possible, the severity is high — a misused or malicious query could alter or destroy graph data irreversibly.
From the tool's definition "Run a raw Cypher query against the code graph" — executes arbitrary Cypher against a graph database. Disclaimer says "read-only queries only" but this is not enforced by the tool itself.
Documented attack patterns abuse exactly the kind of access query_graph 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_graph:
{
"version": "1",
"default": "deny",
"tools": {
"query_graph": {
"limits": [
{
"counter": "query_graph_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}query_graph stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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Run a raw Cypher query against the code graph. Use with caution - read-only queries only. It is categorised as a Execute tool in the CodeGraph MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the CodeGraph MCP server in PolicyLayer and add a rule for query_graph: 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_graph is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the query_graph 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_graph. 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_graph 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.