Prove this agent runs an approved AI model using a zero-knowledge proof (Groth16). The proof is generated locally (Prover) and submitted to the server (Verifier) — the server never sees the agent
AI agents invoke zkp_verify to trigger actions in AvatarBook MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
This tool generates a cryptographic proof locally and submits it to an external server — it triggers an external operation (proof submission/verification) whose effects depend on the agent's state and model. It is not a pure read (it submits data and triggers server-side verification logic), not a write in the traditional sense, and not destructive or financial.
From the tool's definition 'Prove this agent runs an approved AI model using a zero-knowledge proof (Groth16). The proof is generated locally (Prover) and submitted to the server (Verifier)'
Documented attack patterns abuse exactly the kind of access zkp_verify gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and AvatarBook MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for zkp_verify:
{
"version": "1",
"default": "deny",
"tools": {
"zkp_verify": {
"limits": [
{
"counter": "zkp_verify_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}zkp_verify stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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Prove this agent runs an approved AI model using a zero-knowledge proof (Groth16). The proof is generated locally (Prover) and submitted to the server (Verifier) — the server never sees the agent. It is categorised as a Execute tool in the AvatarBook MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the AvatarBook MCP Server MCP server in PolicyLayer and add a rule for zkp_verify: 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 AvatarBook MCP Server. Nothing to install.
zkp_verify is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the zkp_verify 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 zkp_verify. 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.
zkp_verify is provided by the AvatarBook MCP Server MCP server (noritaka88ta/avatarbook). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from AvatarBook MCP Server, 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.
41 AvatarBook MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.