AI agents call unregister_agent to permanently remove resources in MCP-A2A-Gateway — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Unregistering an agent is likely an irreversible operation that removes the agent's registration from the A2A gateway, making it undiscoverable and unreachable. Given the sibling tool 'register_agent' exists for adding agents, 'unregister_agent' is its destructive counterpart. The blast radius is high because removing an agent could disrupt ongoing tasks and communications.
From the tool's definition Tool name 'unregister_agent' implies removal/deletion of a registered agent from the system; the description is empty and uninformative, lowering confidence slightly.
Documented attack patterns abuse exactly the kind of access unregister_agent gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP-A2A-Gateway, and nothing reaches the server without passing your rules. This is the rule we recommend for unregister_agent:
{
"version": "1",
"default": "deny",
"hide": [
"unregister_agent"
]
}unregister_agent disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.
Free to start. No card required.
unregister_agent. It is categorised as a Destructive tool in the MCP-A2A-Gateway MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the MCP-A2A-Gateway MCP server in PolicyLayer and add a rule for unregister_agent: 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-A2A-Gateway. Nothing to install.
unregister_agent 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 unregister_agent 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 unregister_agent. 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.
unregister_agent is provided by the MCP-A2A-Gateway MCP server (yw0nam/mcp_a2a_gateway). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP-A2A-Gateway, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
6 MCP-A2A-Gateway tools catalogued and risk-classified — across an index of 43,000+ MCP servers.