Wait for and return the first full message matching criteria. Best for test flows where an email/SMS may arrive shortly.
AI agents call mailosaur_messages_get to retrieve information from Mailosaur MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and retrieves email/SMS messages based on matching criteria. It has no side effects: it does not create, modify, delete, or execute operations. It simply waits for and returns message content, which is a read operation. Even though it accesses test message infrastructure, the action itself is purely informational retrieval.
From the tool's definition Tool description states 'Wait for and return the first full message matching criteria' — this retrieves message data without modifying, deleting, or executing external actions.
Attacks that exploit this kind of access
Wait for and return the first full message matching criteria. Best for test flows where an email/SMS may arrive shortly. It is categorised as a Read tool in the Mailosaur MCP MCP Server, which means it retrieves data without modifying state.
Register the Mailosaur MCP server in PolicyLayer and add a rule for mailosaur_messages_get: 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 Mailosaur MCP. Nothing to install.
mailosaur_messages_get 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 mailosaur_messages_get 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 mailosaur_messages_get. 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.
mailosaur_messages_get is provided by the Mailosaur MCP server (mrnewdelhi/mailosaur-mcp). 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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