AI agents use end_session to create or update resources in Opencode Personal Knowledge — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Opencode Personal Knowledge environment.
Ending a session modifies the state of a session record (marking it as ended/closed). This is a reversible write operation — sessions are finalized but not deleted. The blast radius is medium since it could prematurely terminate an active session, losing in-progress context, but no data is permanently destroyed.
From the tool's definition End the current or specified session
Documented attack patterns abuse exactly the kind of access end_session gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Opencode Personal Knowledge, and nothing reaches the server without passing your rules. This is the rule we recommend for end_session:
{
"version": "1",
"default": "deny",
"tools": {
"end_session": {
"limits": [
{
"counter": "end_session_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}end_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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End the current or specified session. It is categorised as a Write tool in the Opencode Personal Knowledge MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Opencode Personal Knowledge MCP server in PolicyLayer and add a rule for end_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 Opencode Personal Knowledge. Nothing to install.
end_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 end_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 end_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.
end_session is provided by the Opencode Personal Knowledge MCP server (nocturnlabs/opencode-personal-knowledge). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Opencode Personal Knowledge, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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15 Opencode Personal Knowledge tools catalogued and risk-classified — across an index of 43,000+ MCP servers.