feat(attachments): Require same-envelope delivery

[jjbayer]

DESCRIBE YOUR PR

Over the years, we've had several reports and even incidents around ingesting & billing for orphaned attachments -- that is attachments that were stored even though their events got dropped by inbound filters or rate limiting.

These attachments are unreachable to users, but they still pay for them.

We're closing this gap on the server-side (see INGEST-1169), but for optimal ingestion, SDKs should not send standalone attachments in the first place.

Open questions

• Are there any SDKs that cannot possibly send the attachment in the same envelope due to technical limitations?

IS YOUR CHANGE URGENT?

Help us prioritize incoming PRs by letting us know when the change needs to go live.
Select exactly one option. For deadlines, replace YYYY-MM-DD with the due date. You can update this information later by editing the PR description.

• Urgent deadline (GA date, etc.): YYYY-MM-DD
• Other deadline: YYYY-MM-DD
• No deadline: Not urgent, can wait up to 1 week+

SLA

• Teamwork makes the dream work, so please add a reviewer to your PRs.
• Please give the docs team up to 1 week to review your PR unless you've supplied a deadline.

Thanks in advance for your help!

PRE-MERGE CHECKLIST

Make sure you've checked the following before merging your changes:

• Checked Vercel preview for correctness, including links
• PR was reviewed and approved by any necessary SMEs (subject matter experts)
• PR was reviewed and approved by a member of the Sentry docs team

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated
develop-docs	Ready	Preview	Sep 8, 2026 12:56pm UTC

1 Skipped Deployment

Project	Deployment	Actions	Updated
sentry-docs	Ignored	Preview	Sep 8, 2026 12:56pm UTC