Atomic Mail Agentic

Appearance

JMAP using and inline ops ​

RFC 8620 requires each JMAP request to include a using array: the set of capability URNs that apply to all method calls in that batch. If a method belongs to a URN you did not declare, the request is not valid for a standards-following server.

Full envelope vs bare methodCalls ​

Clients may send either:

  1. Full envelope: { "using": ["urn:ietf:params:jmap:core", ...], "methodCalls": [...] }
  2. Bare array: [["Email/query", {...}, "q0"], ...] — the host then supplies a default using for the envelope it builds.

Atomic Mail MCP (jmap_request) and AgentSkill / CLI use the same default using when you pass only a bare methodCalls array:

  • urn:ietf:params:jmap:core
  • urn:ietf:params:jmap:mail

That pair covers Mailbox/, Email/, Thread/, SearchSnippet/, and other types declared under the mail capability. For built-in recipes and when to add more URNs, use help --topic jmap_cheatsheet (CLI) or the MCP help tool with topic jmap_cheatsheet.

Pitfall: submission, identity, and blob methods ​

If you pass a bare methodCalls array (no envelope) and rely on the default using, you must extend using whenever the batch includes methods that need other URNs, for example:

Methods (examples)Add to using
EmailSubmission/*, Identity/*urn:ietf:params:jmap:submission
Blob/upload, Blob/get, Blob/lookupurn:ietf:params:jmap:blob

Ways to do that:

  • Put a full { "using": [...], "methodCalls": [...] } object in ops / your JSON file, with every URN you need; or
  • MCP: set the tool’s using input array so it includes submission and/or blob in addition to core and mail when your inline ops need them; or
  • Use bundled presets (for example send_mail.json), which already embed the correct using for their method calls.

For a narrative send/read example, see Raw JMAP requests.