[Bug] Long conversations hang indefinitely - OpenCode session/message endpoint #1258

Bug Description

Long conversations hang indefinitely. After ~20-30 messages, OpenChamber stops receiving responses from OpenCode. The generation either spins forever or silently stops.

Environment

• OpenCode version: 1.14.46 (downgraded from 1.14.48)
• OpenChamber version: 1.10.4
• Bun version: 1.3.13
• OS: Arch Linux (cachyos)
• Binary: Using bun for both services, NOT hermes node

Steps to reproduce

1. Start a normal conversation using OpenChamber with OpenCode
2. Continue chatting — after roughly 20-30 messages, responses stop
3. OpenChamber UI shows spinning/loading indefinitely or silent stop
4. Can still use the same session via OpenCode TUI directly
5. Restarting OpenChamber or the session does not fix it — only starting a fresh session helps temporarily

What we tried

• Downgrading OpenCode from 1.14.48 to 1.14.46 — did NOT fix
• Running both services under bun binary (not hermes node) — did NOT fix
• Reinstalling OpenChamber — did NOT fix
• Using OpenCode TUI directly — works fine, same session

Root cause (from Silvenga on #1202)

The session/{session}/message endpoint is handled by OpenCode. Silvenga investigated the code and confirmed the bug is in OpenCode's session/message API endpoint.

Related issues

• OpenChamber: [Bug] Long conversations get stuck indefinitely / no response. #1202 (same bug, still OPEN as of May 13 2026)
• OpenCode: #27310 (regression confirmed, "Replace Bun shell with direct spawn calls")
• Silvenga suggested v1.14.46 but reporter on [Bug] Long conversations get stuck indefinitely / no response. #1202 says it still fails on 1.14.48

Expected behavior

Continue generating responses normally even with long chat histories.