AI agents use register_agent to create or update resources in MCP-A2A-Gateway — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your MCP-A2A-Gateway environment.
Registering an agent creates a new entity in the system and modifies the agent registry, which is a reversible Write operation. Severity is medium because malicious agent registration could enable unauthorized task execution or communication on the gateway, but the operation itself is not destructive or financial.
From the tool's definition Tool name 'register_agent' indicates creation/modification of agent registrations in the A2A protocol system. Description is empty, limiting precision.
Documented attack patterns abuse exactly the kind of access register_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 register_agent:
{
"version": "1",
"default": "deny",
"tools": {
"register_agent": {
"limits": [
{
"counter": "register_agent_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}register_agent 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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register_agent. It is categorised as a Write tool in the MCP-A2A-Gateway MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the MCP-A2A-Gateway MCP server in PolicyLayer and add a rule for register_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.
register_agent 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 register_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 register_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.
register_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.