unblock_sender · Tru MCP: Risk & Policy

WHAT IT DOES

What unblock_sender does on Tru

AI agents use unblock_sender to create or update resources in Tru — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Tru environment.

PARAMETERS

Parameter	Type	Required	Description
`sender_email`	string	Yes	Email address of the sender to unblock

Parameters from the server's own tool schema.

WHY IT NEEDS A POLICY

Why unblock_sender needs a policy

This is a Write action because it modifies state reversibly (a sender can be blocked again). It is not Destructive because the action is undoable. While it relates to payment requests, it does not directly move money or create financial obligations—it only changes permissions for who can send payment requests.

From the tool's definition The tool description states it 'Unblock a previously blocked sender, allowing them to send you payment requests again.' This modifies a blocking/allowlist state that controls whether an entity can initiate payment requests.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

unblock_sender Rate-limited

unblock_sender 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.

View as policy code

policy.json

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

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Tru, so you can run agents against it safely.

FAQ

Questions about unblock_sender

What does the unblock_sender tool do? +

Unblock a previously blocked sender, allowing them to send you payment requests again. Requires login first. It is categorised as a Write tool in the Tru MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

What parameters does unblock_sender accept? +

unblock_sender accepts 1 parameter: sender_email. Required: sender_email. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on unblock_sender? +

Register the Tru MCP server in PolicyLayer and add a rule for unblock_sender: 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 Tru. Nothing to install.

What risk level is unblock_sender? +

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

Can I rate-limit unblock_sender? +

Yes. Add a rate_limit block to the unblock_sender 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 unblock_sender completely? +

Set action: deny in the PolicyLayer policy for unblock_sender. 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 unblock_sender? +

unblock_sender is provided by the Tru MCP server (tru-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.