Summary
diagnose_failed_send is the tool that answers the only question anyone asks about transactional email.
Nobody investigates a successful send. The failures — bounced, suppressed, rejected by DKIM, held by a filter — are where the time goes, and they normally mean reading logs across two systems. A dedicated diagnostic tool is the right thing to build. Note the domain verification prerequisite: without it nothing sends, and that is an infrastructure task rather than a config one.
What it is
Mailchimp's endpoint for their transactional product, Mandrill. Rather than a tool per endpoint it exposes the API itself, plus a diagnostic tool for the question people actually ask.
What you get
- call_api, describe_api, list_api — the transactional API, discoverable and callable
- build_template — construct a template
- diagnose_failed_send — work out why a message did not arrive
- Account status and integration guidance
Requirements
A Transactional API key and a verified sending domain. If the key is restricted, it needs the AI Agents permission group.
Setup effort
Paste a URL with a key — add the endpoint to your client