Non-blocking read. Default drains this agent
AI agents call get_messages to retrieve information from Mcp Switchboard without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves messages from a message queue or buffer. It performs a read operation that queries existing data without creating, modifying, or deleting anything. Even though 'drains' suggests consuming messages from a buffer, this is a standard retrieval pattern (similar to dequeuing) with no destructive intent—the messages are read/accessed, not irreversibly deleted.
From the tool's definition Tool name is 'get_messages' and description states 'Non-blocking read. Default drains this agent'. The verb 'read' combined with 'non-blocking' and 'drains' (consuming/retrieving messages) indicates retrieval of data with no side effects.
Attacks that exploit this kind of access
Non-blocking read. Default drains this agent. It is categorised as a Read tool in the Mcp Switchboard MCP Server, which means it retrieves data without modifying state.
Register the Mcp Switchboard MCP server in PolicyLayer and add a rule for get_messages: 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 Mcp Switchboard. Nothing to install.
get_messages 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 get_messages 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 get_messages. 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.
get_messages is provided by the Mcp Switchboard MCP server (jemplayer82/mcp-switchboard). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
get_messages is one line of Mcp Switchboard's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
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