AI agents call list_sessions to retrieve information from Gemini without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns information about existing sessions. It has no side effects, does not modify data, does not execute code or commands, and does not delete or create resources. It is a simple informational read operation with minimal risk if misused by an AI agent.
From the tool's definition Tool name is 'list_sessions' and description states 'List all active ACP sessions managed by the bridge.' The verb 'list' is a read-only operation that retrieves session information without modifying or executing anything.
Documented attack patterns abuse exactly the kind of access list_sessions gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Gemini, and nothing reaches the server without passing your rules. This is the rule we recommend for list_sessions:
{
"version": "1",
"default": "deny",
"tools": {
"list_sessions": {}
}
}list_sessions is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List all active ACP sessions managed by the bridge. It is categorised as a Read tool in the Gemini MCP Server, which means it retrieves data without modifying state.
Register the Gemini MCP server in PolicyLayer and add a rule for list_sessions: 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 Gemini. Nothing to install.
list_sessions 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_sessions 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_sessions. 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_sessions is provided by the Gemini MCP server (shenyunhuan/gemini_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 4 Gemini tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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4 Gemini tools catalogued and risk-classified — across an index of 42,500+ MCP servers.