[Bug] Log rotation stops working on Windows; opencode.log grows indefinitely

Description

On Windows, OpenCode log rotation appears to stop working after some time. Instead of rotating recent logs, all new log output is appended to a single live opencode.log, which has grown to ~170 MB.

Observed log directory:

%USERPROFILE%.local\share\opencode\log\

opencode.log 170,851,996 B Sep 3 21:33
2026-06-10T124216.log 5,772 B Jun 10
2026-06-09T185008.log 7,341 B Jun 9
... 11 rotated files total, all from Jun 9-10

There have been many OpenCode sessions since June 10, but no newer rotated log files were created. opencode.log has continued growing instead.

This is particularly problematic when using --log-level DEBUG, because the live file can grow quickly and there is no bounded retention in practice.

Expected behavior

The live log should continue rotating according to OpenCode's normal log-retention policy, keeping the log directory bounded.

Actual behavior

Rotation stopped after June 10. Since then:

• no new rotated files are created;
• opencode.log keeps accumulating output across sessions;
• the current live log reached ~170 MB.

Plugins

No response

OpenCode version

1.3.14.0

Steps to reproduce

I do not yet have a minimal deterministic trigger, but the failure is persistent on this machine:

1. Run OpenCode normally across multiple sessions on Windows.
2. Inspect %USERPROFILE%.local\share\opencode\log.
3. Observe that old rotated files remain unchanged while opencode.log continues growing across subsequent sessions.
4. Running with opencode --log-level DEBUG increases the growth rate but is not required for the rotation failure.

Screenshot and/or share link

Additional observations

• The stale rotated files are all dated June 9–10.
• The current opencode.log was still actively written on Sep 3.
• This report is specifically about log rotation/retention; it is separate from any process-exit or memory-growth issue.

Operating System

Windows 11, build 10.0.26200.2.0.0

Terminal

PowerShell / Git Bash