Send Email MCP ServerVerifiedFeatured

Send emails from natural language prompts.

MCP endpoint
https://next.hal9.ai/mcp/mcpbuild/send-email

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First time connecting an MCP? See Installing MCPs for setup steps in Claude, Claude Code, and other clients.

What it does

send-email turns a plain-language request into a real email. Instead of filling out a rigid "to / subject / body" form, an agent (or a human) just describes what they want sent, and the MCP figures out the rest:

send email to javier@hal9.ai with text hello!

Under the hood, the prompt is passed to a language model with a single send_email tool definition. The model extracts the recipient, infers a short subject when one isn't given, and writes the body — then the MCP calls the email provider (Resend) to actually send it.

How agents use this MCP

Once connected, an agent sees a single tool — send_email — with three parameters:

Parameter	Description
to	Recipient email address
subject	Subject line — inferred from the request if not stated
text	Plain-text body of the email

The agent doesn't need to call the tool directly with structured arguments — it can just be asked in plain English, and it will:

1. Read the request
   e.g. "email the team lead at jane@acme.com that the report is ready"
2. Fill in the gaps
   Infers a subject and drafts the body text if the user didn't spell them out
3. Call send_email
   The MCP sends the message via Resend and returns a delivery confirmation with a message id

Typical uses: notifying someone from an automated workflow, letting an agent follow up on a task by email, or wiring "email X" into a larger multi-step agent without writing any email-sending code.

Self-host or run locally

send-email is open source and built on the Hal9 agent structure. You can run it yourself instead of using the hosted version:

cd send-email
pip install -r requirements.txt
export GROQ_API_KEY=…
export RESEND_API_KEY=…
echo "send email to you@example.com with text hello!" | python app.py