Clear all tracked identifiers and start fresh.
AI agents call clear_session to permanently remove resources in MCP Pyrefly — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
This tool irreversibly removes all tracked session data (identifiers), which cannot be undone once cleared. The 'start fresh' language confirms the deletion is a reset with no recovery path. Severity is medium because it only affects session/tracking state rather than production code or financial data.
From the tool's definition Clear all tracked identifiers and start fresh
Risk signalsBulk/mass operation — affects multiple targets
Attacks that exploit this kind of access
Clear all tracked identifiers and start fresh. It is categorised as a Destructive tool in the MCP Pyrefly MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the MCP Pyrefly MCP server in PolicyLayer and add a rule for clear_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 MCP Pyrefly. Nothing to install.
clear_session is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the clear_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 clear_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.
clear_session is provided by the MCP Pyrefly MCP server (kimasplund/mcp-pyrefly). 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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