[Langfuse] Search and filter sessions with extended criteria including text search, user ID, trace count range, and cost range. Combines API-level and client-side filtering.
AI agents call langfuse_search_sessions to retrieve information from Shepherd MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries observability data (Langfuse sessions) and applies filters to return matching results. No create, update, delete, or execute operations are possible—it only retrieves and analyzes existing session data. The blast radius of misuse is limited to information disclosure, making it low severity.
From the tool's definition Tool is explicitly described as 'Search and filter sessions' with no mention of modifications, deletions, or side effects.
Attacks that exploit this kind of access
[Langfuse] Search and filter sessions with extended criteria including text search, user ID, trace count range, and cost range. Combines API-level and client-side filtering. It is categorised as a Read tool in the Shepherd MCP MCP Server, which means it retrieves data without modifying state.
Register the Shepherd MCP server in PolicyLayer and add a rule for langfuse_search_sessions: 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 Shepherd MCP. Nothing to install.
langfuse_search_sessions 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 langfuse_search_sessions 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 langfuse_search_sessions. 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.
langfuse_search_sessions is provided by the Shepherd MCP server (neuralis-in/shepherd-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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