Search for similar nodes using vector similarity. Returns top-K most similar nodes.
AI agents call search_similar_nodes to retrieve information from Code Graph Knowledge System without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries data from the Neo4j knowledge graph using vector similarity matching. It has no side effects, does not execute code, does not modify or delete data, and does not create financial obligations. It is a pure read operation analogous to a search or query function.
From the tool's definition Tool performs 'Search for similar nodes using vector similarity. Returns top-K most similar nodes.' - a query operation with no modification or execution of code.
Documented attack patterns abuse exactly the kind of access search_similar_nodes gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Code Graph Knowledge System, and nothing reaches the server without passing your rules. This is the rule we recommend for search_similar_nodes:
{
"version": "1",
"default": "deny",
"tools": {
"search_similar_nodes": {}
}
}search_similar_nodes is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Search for similar nodes using vector similarity. Returns top-K most similar nodes. It is categorised as a Read tool in the Code Graph Knowledge System MCP Server, which means it retrieves data without modifying state.
Register the Code Graph Knowledge System MCP server in PolicyLayer and add a rule for search_similar_nodes: 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 Code Graph Knowledge System. Nothing to install.
search_similar_nodes 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 search_similar_nodes 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 search_similar_nodes. 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.
search_similar_nodes is provided by the Code Graph Knowledge System MCP server (royisme/codebase-rag). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Code Graph Knowledge System, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
30 Code Graph Knowledge System tools catalogued and risk-classified — across an index of 43,000+ MCP servers.