Hello,
On Windows, Codex MCP OAuth login for the Supabase MCP service fails before browser authentication with “error decoding response body”.
Diagnostics using curl and an independent raw TLS client observed:
- Affected service: mcp.supabase.com.
- Some HTTP responses advertise Transfer-Encoding: chunked, but the received body contains JSON without chunk framing.
- The observed certificate issuer is “Avast Web/Mail Shield Root”, indicating HTTPS inspection.
- Gzip-compressed protected-resource metadata and issuer metadata are readable.
- No proxy environment variables were found; WinINET proxy is disabled and WinHTTP reports direct access.
Avast’s responsibility for the malformed framing has NOT been established. The exact response causing the CLI failure is also unconfirmed.
Could you advise how to compare framing before and after HTTPS inspection while keeping protection enabled, and identify an appropriate supported remedy?
Environment: Windows 25H2, OS build 26200.9457; Avast 26.9.
Thank you.