Purpose: Fire an event to trigger automations for a specific contact. When to use: - User wants to trigger an automation workflow for a contact - Testing an automation by sending a test event Workflow: create-event (if needed) → create-automation (if needed) → send-event Important: - The event na...
AI agents invoke send-event to trigger actions in Email Sending MCP. 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 triggers automation workflows, which can initiate chains of actions (e.g., sending emails, updating contacts, running sequences) based on the fired event. The downstream effects depend on how the automation is configured, making this an Execute-category tool. Misuse could cause unintended automation chains to fire for contacts at scale, hence high severity.
From the tool's definition Fire an event to trigger automations for a specific contact
Documented attack patterns abuse exactly the kind of access send-event gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Email Sending MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for send-event:
{
"version": "1",
"default": "deny",
"tools": {
"send-event": {
"limits": [
{
"counter": "send-event_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}send-event 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.
Free to start. No card required.
Purpose: Fire an event to trigger automations for a specific contact. When to use: - User wants to trigger an automation workflow for a contact - Testing an automation by sending a test event Workflow: create-event (if needed) → create-automation (if needed) → send-event Important: - The event name must match the trigger event name in an automation for it to fire. - Identify the contact by either contactId OR email, not both. - The payload is optional and can contain any key-value data that the automation steps can reference via event.* variables. It is categorised as a Execute tool in the Email Sending MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Email Sending MCP server in PolicyLayer and add a rule for send-event: 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 Email Sending MCP. Nothing to install.
send-event 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 send-event 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 send-event. 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.
send-event is provided by the Email Sending MCP server (resend/resend-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 77 Email Sending MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
77 Email Sending MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.