For agents
Your agent can already send email. Now it can send it right.
Herald ships an MCP server with send, draft, and report tools, and a skill file that teaches your coding agent the contract — idempotency keys, rate limits, template syntax, and when to ask a human first.
Send a welcome email to everyone who signed up today, from Mara, with a link to the quickstart.
From Mara at Herald · To 128 people
Welcome to Herald
Your first send is three lines of code away.
- Queued 0.2s
- Sent 1.1s
- Delivered 1.9s
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Docs
Send API
One POST to send. Templates, attachments, idempotency keys, and a delivery event for every message.
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Docs
MCP server
Give your agent tools to send, draft campaigns, manage contacts, and read delivery stats.
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Docs
Agent skill
A SKILL.md your coding agent reads once and gets Herald right on the first try.
The agent skill
One file, and your agent gets Herald right.
Install the skill and your coding agent learns the send contract, the idempotency rules, the template syntax, and the mistakes that get a domain throttled — before it writes a line.
- Send, draft, and report tools over MCP
- A SKILL.md with the rules and the gotchas
- Works in Claude Code, Codex, Cursor, and Copilot
$ npx herald@latest skill add
Added .herald/SKILL.md (2.1 KB)
$ claude mcp add herald -- npx herald mcp
Registered 6 tools: send, draft, list_contacts, stats, warmup, inbound
$ herald send --to team@acme.com --subject "Hello from an agent"
Delivered in 1.3s · id msg_8f2k
Agent integrations
Works with the agent you already use.
Ask around.
See what your favourite model says about Herald, then decide for yourself.
Give your agent a send key.
Scoped keys let you decide which tools an agent may call. Start with drafts only, then let it send.