Send a new email. Requires either textBody or htmlBody (or both). The identityId parameter is optional — if omitted, the server uses the default sending identity.
AI agents use send_email to create or update resources in JMAP MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your JMAP MCP environment.
This tool creates new email messages and sends them via JMAP, which is a reversible write operation (emails can be deleted/unsent in many systems, though delivery cannot always be prevented). It does not irreversibly delete data (not Destructive), does not move money (not Financial), and does not execute arbitrary code (not Execute).
From the tool's definition Tool name 'send_email' and description 'Send a new email' indicates creation of new email messages. The parameters allow specifying textBody/htmlBody and optional identityId, confirming the tool creates and sends new email communications.
Documented attack patterns abuse exactly the kind of access send_email gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and JMAP MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for send_email:
{
"version": "1",
"default": "deny",
"tools": {
"send_email": {
"limits": [
{
"counter": "send_email_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}send_email stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Send a new email. Requires either textBody or htmlBody (or both). The identityId parameter is optional — if omitted, the server uses the default sending identity. It is categorised as a Write tool in the JMAP MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the JMAP MCP server in PolicyLayer and add a rule for 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 JMAP MCP. Nothing to install.
send_email is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the 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 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.
send_email is provided by the JMAP MCP server (wyattjoh/jmap-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 11 JMAP MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
11 JMAP MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.