Scheduled agent: HTTP 403 on git push of binary (~7 MB) since 2026-05-08

Summary

Scheduled remote agent (Claude Scheduler / /schedule skill) consistently fails to git push binary content (~7 MB MP3) to a public GitHub repo since 2026-05-08. Text pushes from the same routine succeed.

Symptom

The agent does:

1. Compose briefing text
2. Generate ~7 MB MP3 via OpenAI TTS
3. git push text file (briefings/YYYY-MM-DD.txt, ~5 KB) — succeeds
4. git push MP3 file (webpages/morning-briefing.mp3, ~7 MB) — fails with HTTP 403 from a proxy

The agent's transcript also notes that falling back to the mcp__github__* MCP tools fails because the base64-encoded MP3 (~10 MB) is too large for tool parameter limits.

Timeline

• Working for several weeks before 2026-05-08
• Broken from 2026-05-08 onwards (every day since, same 403)
• Possibly related to the GitHub IP range incident around 2026-05-07 (status page marks it resolved but may not be fully fixed for binary uploads from scheduled agents specifically)

Repro

Any scheduled agent that:

1. Generates a multi-MB binary file
2. Tries to git push it to a public GitHub repo over HTTPS

(Cannot share the exact agent prompt publicly because it contains personal config; happy to provide more detail privately.)

Workaround applied

Moved TTS + git push of binary into a GitHub Actions workflow on the destination repo, so the binary commit happens from the GitHub runner (which has unrestricted egress). The scheduled agent now only pushes the text file; the workflow generates and commits the MP3.

Asks

1. Is this a known regression on the scheduler's egress proxy?
2. Is there a documented size or content-type cap on outbound binary HTTP from scheduled agents?
3. Is there a recommended pattern for scheduler-side binary uploads to GitHub, or is the GitHub-Actions-side approach the new recommended pattern?

Happy to share full transcript or the failing repo if helpful.