postmark_send_email
Send a transactional email via Postmark. Supports HTML and plain text.
This record as markdown: /tools/io-github-malamutemayhem-unclick-mcp-server/postmark-send-email.md
What postmark_send_email does on UnClick
AI agents invoke postmark_send_email to trigger actions in UnClick. 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.
| Parameter | Type | Required | Description |
|---|---|---|---|
cc | string | — | CC email address(es) |
to | string | Yes | Recipient email address |
bcc | string | — | BCC email address(es) |
tag | string | — | Tag for categorizing messages |
from | string | Yes | Sender email address (must be verified in Postmark) |
api_key | string | Yes | Postmark server token |
subject | string | Yes | Email subject line |
reply_to | string | — | Reply-to email address |
html_body | string | — | HTML email body |
text_body | string | — | Plain text email body |
message_stream | string | — | Message stream ID (default: outbound) |
Parameters from the server's own tool schema.
Why postmark_send_email is rated High
Sending an email is an external operation with real-world side effects — it delivers messages to recipients outside the system. It is not merely writing data to a store; it triggers an external communication action. Misuse could enable phishing, spam, or impersonation at scale, making severity high.
From the tool's definition Send a transactional email via Postmark. Supports HTML and plain text.
Risk signalsHandles credentials or secrets (api_key) · High parameter count (11 properties)
Attacks that exploit this kind of access
The rule that runs postmark_send_email safely
PolicyLayer is an MCP gateway: it sits between your AI agents and UnClick, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For postmark_send_email, this is the rule to start with:
postmark_send_email 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.
The button opens the PolicyLayer dashboard: create your workspace, connect UnClick, apply this rule, and every postmark_send_email call is checked against it from then on.
Questions about postmark_send_email
Send a transactional email via Postmark. Supports HTML and plain text. It is categorised as a Execute tool in the UnClick MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
postmark_send_email accepts 11 parameters: cc, to, bcc, tag, from, api_key, subject, reply_to, html_body, text_body, message_stream. Required: to, from, api_key, subject. The full parameter table on this page comes from the server's own tool schema.
Register the UnClick MCP server in PolicyLayer and add a rule for postmark_send_email: 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.
postmark_send_email 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 postmark_send_email 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 postmark_send_email. 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.
postmark_send_email 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.
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