[BUG] opencode export outputs truncated JSON when piped #14948

Description

opencode export <sessionID> returns truncated JSON when stdout is piped for sessions with large file attachments (5-10 MB). The same session export is valid when redirected directly to a file (>). This breaks tools that consume export output via pipe (e.g. jq, plugins calling opencode export through subprocess stdout capture).

Plugins

None

OpenCode version

1.2.10

Steps to reproduce

I faced this with PDFs:

1. Get a 5+ MB PDF, e.g., download from https://arxiv.org/pdf/1409.0575.
2. Create a new session with a prompt like "Read 1409.0575.pdf. Reply nothing."
3. Piped export fails: opencode export <sessionID> | jq . >/dev/null
4. Redirect to file works: opencode export <sessionID> > good.json; jq . good.json >/dev/null

Expected behavior:
Piped output should be valid JSON and identical (content-complete) to direct redirect output.

Screenshot and/or share link

No response

Operating System

macOS 26.2

Terminal

No response