특정 사용자의 메시지를 이름이나 username으로 검색합니다.
AI agents call search_user_messages to retrieve information from Mattermost MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves historical message data from Mattermost based on user identity filters. It performs a read-only search operation with no side effects—no data is created, modified, deleted, or executed. The blast radius of misuse is low (exposure of messages a user has access to view), and the capability aligns with standard information retrieval patterns.
From the tool's definition Tool name 'search_user_messages' and description 'searches messages by a specific user's name or username' indicates querying/retrieving message data without modification or deletion.
Attacks that exploit this kind of access
특정 사용자의 메시지를 이름이나 username으로 검색합니다. It is categorised as a Read tool in the Mattermost MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Mattermost MCP Server MCP server in PolicyLayer and add a rule for search_user_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 Mattermost MCP Server. Nothing to install.
search_user_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 search_user_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 search_user_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.
search_user_messages is provided by the Mattermost MCP Server MCP server (jhanglim/mattermost-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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