postmark_send_batch · UnClick MCP: Risk & Policy

WHAT IT DOES

What postmark_send_batch does on UnClick

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

PARAMETERS

Parameter	Type	Required	Description
`api_key`	string	Yes	Postmark server token
`messages`	array	Yes	Array of email message objects (same fields as send_email)

Parameters from the server's own tool schema.

WHY IT NEEDS A POLICY

Why postmark_send_batch needs a policy

This tool sends (creates) email messages via the Postmark service. Sending emails is a reversible write operation—messages can be unsent or deleted in some systems, and the primary effect is data creation/transmission rather than destruction or code execution.

From the tool's definition Tool name 'postmark_send_batch' and description 'Send multiple emails in a single Postmark API call' clearly indicate the tool creates and sends email messages.

Risk signalsHandles credentials or secrets (api_key)

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

postmark_send_batch Rate-limited

postmark_send_batch 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": {
    "postmark_send_batch": {
      "limits": [
        {
          "counter": "postmark_send_batch_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 UnClick, so you can run agents against it safely.

FAQ

Questions about postmark_send_batch

What does the postmark_send_batch tool do? +

Send multiple emails in a single Postmark API call (up to 500 messages). It is categorised as a Write tool in the UnClick MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

What parameters does postmark_send_batch accept? +

postmark_send_batch accepts 2 parameters: api_key, messages. Required: api_key, messages. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on postmark_send_batch? +

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

What risk level is postmark_send_batch? +

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

Can I rate-limit postmark_send_batch? +

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

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

postmark_send_batch is provided by the UnClick MCP server (@unclick/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.