Gmail内で指定したクエリに一致するメールを検索します。 queryパラメータはGmailの検索クエリ形式で指定します。 例:
AI agents call gmail_search_messages to retrieve information from Mcp Gmail Gas without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves or queries email data from a Gmail account without creating, modifying, deleting, or executing operations. While it accesses potentially sensitive email content, the read-only nature and reliance on user-provided search queries places it squarely in the Read category.
From the tool's definition Tool name 'gmail_search_messages' and description indicate it performs a search operation ('検索します' means 'searches') matching a query in Gmail. It retrieves messages without modifying, deleting, or executing code.
Documented attack patterns abuse exactly the kind of access gmail_search_messages gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mcp Gmail Gas, and nothing reaches the server without passing your rules. This is the rule we recommend for gmail_search_messages:
{
"version": "1",
"default": "deny",
"tools": {
"gmail_search_messages": {}
}
}gmail_search_messages is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Gmail内で指定したクエリに一致するメールを検索します。 queryパラメータはGmailの検索クエリ形式で指定します。 例:. It is categorised as a Read tool in the Mcp Gmail Gas MCP Server, which means it retrieves data without modifying state.
Register the Mcp Gmail Gas MCP server in PolicyLayer and add a rule for gmail_search_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 Gmail Gas. Nothing to install.
gmail_search_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 gmail_search_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 gmail_search_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.
gmail_search_messages is provided by the Mcp Gmail Gas MCP server (kazuph/mcp-gmail-gas). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Mcp Gmail Gas, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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3 Mcp Gmail Gas tools catalogued and risk-classified — across an index of 43,000+ MCP servers.