AI agents call graph_traverse to retrieve information from Mementos without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs multi-hop traversal across a graph structure and returns results without creating, modifying, deleting, or executing external operations. It is purely informational/investigative in nature. The filtering parameters (direction, relation-type) are query constraints, not actions.
From the tool's definition Tool description states it 'Returns all paths with entities and relations' - a retrieval operation with no modification or side effects. Graph traversal is a query operation that reads existing data structure.
Attacks that exploit this kind of access
Multi-hop graph traversal from an entity. Returns all paths with entities and relations at each hop. Supports direction and relation-type filtering. It is categorised as a Read tool in the Mementos MCP Server, which means it retrieves data without modifying state.
Register the Mementos MCP server in PolicyLayer and add a rule for graph_traverse: 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 Mementos. Nothing to install.
graph_traverse 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 graph_traverse 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 graph_traverse. 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.
graph_traverse is provided by the Mementos MCP server (@hasna/mementos). 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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