List all active agents in a project
AI agents call list_active_agents to retrieve information from A2AMCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and displays a list of active agents, which is a read-only operation with no side effects. It queries state but does not modify, delete, or execute anything. The blast radius is minimal—knowing which agents are active provides coordination visibility but cannot directly cause harm if misused by an AI agent.
From the tool's definition Tool name 'list_active_agents' and description 'List all active agents in a project' indicate a query operation that retrieves status information without modifying or executing operations.
Documented attack patterns abuse exactly the kind of access list_active_agents gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and A2AMCP, and nothing reaches the server without passing your rules. This is the rule we recommend for list_active_agents:
{
"version": "1",
"default": "deny",
"tools": {
"list_active_agents": {}
}
}list_active_agents 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 agents in a project. It is categorised as a Read tool in the A2AMCP MCP Server, which means it retrieves data without modifying state.
Register the A2A MCP server in PolicyLayer and add a rule for list_active_agents: 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 A2AMCP. Nothing to install.
list_active_agents 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_active_agents 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_active_agents. 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_active_agents is provided by the A2A MCP server (webdevtodayjason/a2amcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from A2AMCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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17 A2AMCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.