Browse MCP servers from the PulseMCP Sub-Registry. Returns a paginated list of active and deprecated servers with their names, descriptions, and metadata. Deleted servers are excluded by default. Use search to filter by name or description. Use cursor for pagination through large result sets.
AI agents call list_servers to retrieve information from Langfuse Observability 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 metadata about MCP servers from a registry. It performs filtering and pagination but does not create, modify, delete, or execute any operations. The blast radius of misuse is minimal — an AI agent could only over-query or spam requests, causing potential rate-limiting, but cannot damage data or trigger unintended actions.
From the tool's definition Tool name 'list_servers' and description states it 'Browse MCP servers', 'Returns a paginated list' and uses 'search to filter' and 'cursor for pagination' — all read-only query operations with no side effects.
Attacks that exploit this kind of access
Browse MCP servers from the PulseMCP Sub-Registry. Returns a paginated list of active and deprecated servers with their names, descriptions, and metadata. Deleted servers are excluded by default. Use search to filter by name or description. Use cursor for pagination through large result sets. It is categorised as a Read tool in the Langfuse Observability MCP Server, which means it retrieves data without modifying state.
Register the Langfuse Observability MCP server in PolicyLayer and add a rule for list_servers: 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 Langfuse Observability. Nothing to install.
list_servers 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 list_servers 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 list_servers. 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.
list_servers is provided by the Langfuse Observability MCP server (langfuse-observability-mcp-server). 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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