signature_icp_create

THE RISK

Medium Risk

Why signature_icp_create needs a policy

This tool creates a new digital signature envelope, which is a Write operation (creating a new resource). However, in a payment/financial protocol context (AP2 — Agent-to-Agent Payment Protocol), creating legally-binding ICP-Brasil digital signature envelopes can authorize financial transactions or legal commitments, making misuse high severity.

From the tool's definition Create an ICP-Brasil digital signature envelope for one or more documents. Returns envelope_id + signers

Documented attack patterns abuse exactly the kind of access signature_icp_create gives an agent:

POLICY

How to control signature_icp_create

PolicyLayer is an MCP gateway — it sits between your AI agents and Mcp Ap2, and nothing reaches the server without passing your rules. This is the rule we recommend for signature_icp_create:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "signature_icp_create": {
      "limits": [
        {
          "counter": "signature_icp_create_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

signature_icp_create 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.

Create a free account and register Mcp Ap2 — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Mcp Ap2 tools

Financial authorize_transaction Authorize a transaction (reserve funds without capturing) via Braintree GraphQL authorizeP Financial block_card Block a card temporarily (reversible). Use for lost-card or fraud-suspected flows. Card st Financial cancel_bill Cancel a pending bill Financial cancel_collection Cancel a scheduled collection request Financial cancel_credit Cancel an authorized-but-uncaptured credit payment. Financial cancel_debit Cancel a debit-card payment by Getnet payment_id. Financial cancel_invoice Cancel/void an authorized invoice (FECancel — limited to certain types/conditions) Financial cancel_order Cancel an order, optionally restocking and refunding

All 1300 Mcp Ap2 tools →

Write tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about signature_icp_create

What does the signature_icp_create tool do? +

Create an ICP-Brasil digital signature envelope for one or more documents. Returns envelope_id + signers. It is categorised as a Write tool in the Mcp Ap2 MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on signature_icp_create? +

Register the Mcp Ap2 MCP server in PolicyLayer and add a rule for signature_icp_create: 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 Ap2. Nothing to install.

What risk level is signature_icp_create? +

signature_icp_create is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit signature_icp_create? +

Yes. Add a rate_limit block to the signature_icp_create 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.

How do I block signature_icp_create completely? +

Set action: deny in the PolicyLayer policy for signature_icp_create. 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.

What MCP server provides signature_icp_create? +

signature_icp_create is provided by the Mcp Ap2 MCP server (@codespar/mcp-ap2). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Mcp Ap2 tool call.

Start from Mcp Ap2, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →