An AI agent's email summary should remain traceable to the message it summarized. Preserve the original message, identify every derived representation and define how attachments and retention work before letting an inbox feed an automated workflow.
The Ruby on Rails catalogue, observed on October 3, 2026, includes Revdoku. Its listing describes agent inboxes that store original EML, decoded JSON and Markdown with attachments, accessible through several interfaces. Rails is a declared stack association; the listing does not establish its internal mailbox implementation or retention configuration.
Separate the original from the useful representation
An original email can contain headers, alternative body formats and attachments that are absent from a simplified text view. Markdown is convenient for reading, but it should not silently replace the source when exact wording, sender information or an attachment matters.
Assign a stable message identity and record which parser produced each derived version. If extraction rules change, retain a way to explain why the current representation differs from an earlier agent run. A regenerated summary should not look like an unchanged original.
For an evaluation, use a synthetic message containing plain text, formatted text and a harmless attachment. Check which parts are preserved, omitted or transformed. The objective is understandable provenance, not identical visual rendering in every representation.
Understand the framework's lifecycle without assuming it
Rails Action Mailbox documents inbound processing, original-message storage and lifecycle handling, including configurable cleanup. These facilities provide implementation questions to ask; they are not proof that a Rails-labelled product uses the same components or defaults.
Ask the provider how long original messages, attachments and extracted content are retained. Record whether deletion applies consistently across those stores and whether an authorized export preserves the relationships between them.
A retention promise should also identify the operational owner. An application setting, bucket lifecycle and backup policy may operate independently, so one visible Delete button does not explain the entire lifecycle.
Treat message content as untrusted input
An email can contain requests, quoted instructions and misleading claims. Those are data to inspect, not authorization for an agent to change permissions, send messages or access another mailbox. Keep application policy and authenticated user intent outside the message body.
In a controlled trial, include harmless text that asks the agent to ignore its normal task. The expected result is that the text can be summarized as content without changing the agent's permitted actions. Do not use real customer correspondence for exploratory prompt-injection testing.
Attachments need their own access and processing limits. A safe preview does not establish that every downstream parser, download link or model input follows the same policy.
Produce a traceable handoff
A useful agent result references the message identity, representation version and relevant attachment rather than copying a large inbox into an opaque summary. Reviewers should be able to inspect the evidence they are permitted to see.
Keep access failures explicit. If an attachment is unavailable, the result should say so instead of implying it was reviewed. Pair this evidence review with the Rails inbox job replay guide to examine what happens when processing is interrupted or repeated.
Stardew Valley Tracker
IcyZip
Xeramail Temp Mail