Close a specific session by session ID. Ask before closing if the user might still need it.
AI agents use close_session to create or update resources in NotebookLM MCP Structured — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your NotebookLM MCP Structured environment.
This tool creates a side effect by altering the state of a session resource. It is not a simple read operation (no data retrieval), nor is it destructive (sessions are not permanently deleted, and the action is reversible through re-authentication or session recreation).
From the tool's definition The tool description states it closes a specific session by session ID, which modifies the state of a session resource by terminating it. This is a reversible action (sessions can typically be reopened or recreated).
Documented attack patterns abuse exactly the kind of access close_session gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and NotebookLM MCP Structured, and nothing reaches the server without passing your rules. This is the rule we recommend for close_session:
{
"version": "1",
"default": "deny",
"tools": {
"close_session": {
"limits": [
{
"counter": "close_session_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}close_session stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Close a specific session by session ID. Ask before closing if the user might still need it. It is categorised as a Write tool in the NotebookLM MCP Structured MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the NotebookLM MCP Structured MCP server in PolicyLayer and add a rule for close_session: 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 NotebookLM MCP Structured. Nothing to install.
close_session is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the close_session 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 close_session. 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.
close_session is provided by the NotebookLM MCP Structured MCP server (paolodalprato/notebooklm-mcp-structured). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 15 NotebookLM MCP Structured tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
15 NotebookLM MCP Structured tools catalogued and risk-classified — across an index of 42,500+ MCP servers.