opencode v1.18.31: ACP session restore fixes, remote config error surfacing

opencode v1.18.31, released September 14, 2026, is a stability release focused on session state and config error handling.

Core

• ACP session restore: model, effort, mode, and reasoning chunk boundaries are now correctly restored when loading, resuming, or forking sessions (thanks @JacobNWolf). Sessions picked up via the Agent Client Protocol no longer lose their configured reasoning settings.

TUI

• Remote config auth errors are now shown during startup, and the TUI exits with a failure status instead of silently continuing — org-managed setups that fail .well-known/opencode auth now fail loudly.

Extensions

• GitHub Copilot models now request summarized adaptive thinking, improving reasoning trace quality on Copilot-backed sessions.

Community contributions this cycle also included batch workspace block endpoints for the console (@heimoshuiyu).