radmail-mcp — Claude Code MCP server: agent inbox with a hard stop
An MCP server that lets an agent triage a mailbox, track commitments and draft replies, while money and banking-change mail never gets a draft.
claude mcp add --transport http radmail-mcp https://radmail.ai/api/mcp/sandboxWhat radmail-mcp does
RadMail puts an inbox behind MCP tools. One triage_inbox call returns the urgent lane, every open commitment and every hard stop. Around it sit list_right_now, list_commitments, search, read_email and why_surfaced, which spells out in plain words what pushed a message up.
The part that matters is the refusal. Five classes get no draft at all: money, changed banking details, first contact, a decision, and prompt injection. The reasoning is blunt — a ready-made reply on a wire-change thread makes saying yes easier than reading it, so the person writes that one themselves. The refusal lives in code and can only be tightened, never relaxed.
A sandbox engine starts by default: heuristics, in-memory, no credentials. Point it at a real mailbox with RADMAIL_API_KEY, and search, list_commitments and list_right_now read that inbox without writing to it. The trade-off is real: a banking-change notice arriving overnight will have nothing waiting for approval. Want a draft on every thread, money included? Then this is the wrong server.
Install over HTTP at https://radmail.ai/api/mcp/sandbox, or run it locally with npx -y radmail-mcp.
What it helps with
- triage an inbox and surface what cannot wait
- find one message by sender or subject without grepping files
- collect open promises together with their due windows
- explain why a message landed in the urgent lane
- check a domain's SPF, DKIM and DMARC without a key
Example prompts for the agent
- Call
triage_inboxand show me the urgent lane - Find the vendor email about updated banking details
- Run
check_send_domainfor the client's domain
How to install radmail-mcp
1Platform CLI: remote server
claude mcp add --transport http radmail-mcp https://radmail.ai/api/mcp/sandbox2Platform CLI
claude mcp add radmail-mcp -- npx -y radmail-mcp1Platform CLI: remote server
codex mcp add radmail-mcp --url https://radmail.ai/api/mcp/sandbox2Platform CLI
codex mcp add radmail-mcp -- npx -y radmail-mcpConfig file
{
"mcpServers": {
"radmail-mcp": {
"url": "https://radmail.ai/api/mcp/sandbox"
}
}
}{
"mcpServers": {
"radmail-mcp": {
"command": "npx",
"args": [
"-y",
"radmail-mcp"
]
}
}
}Config file
{
"servers": {
"radmail-mcp": {
"type": "http",
"url": "https://radmail.ai/api/mcp/sandbox"
}
}
}{
"servers": {
"radmail-mcp": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"radmail-mcp"
]
}
}
}1Platform CLI: remote server
gemini mcp add -t http radmail-mcp https://radmail.ai/api/mcp/sandbox2Platform CLI
gemini mcp add radmail-mcp npx -y radmail-mcpStep by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about radmail-mcp
How do I install radmail-mcp in Claude Code?
Over HTTP: claude mcp add --transport http radmail-mcp https://radmail.ai/api/mcp/sandbox. Or locally: claude mcp add radmail-mcp -- npx -y radmail-mcp.
What does radmail-mcp do?
It triages incoming mail, keeps a list of open commitments, searches messages and prepares reply drafts. For money, banking changes, first contact, decisions and injected instructions it offers no draft — a person writes that reply.
Do I need an API key?
Not for the sandbox: triage_inbox without a token provisions a free tenant and returns a triage right away. To work with your own inbox, set RADMAIL_API_KEY — search, commitments and the urgent lane then read real mail, read-only.
