1.18.30 (Homebrew, macOS arm64): every prompt fails with "failed to send prompt" — TypeError 'a.name' in SystemPrompt.environment #48903

Environment

• opencode 1.18.30, installed via Homebrew (anomalyco/tap, bottle opencode--1.18.30.arm64_tahoe)
• macOS, arm64 (Apple Silicon / Tahoe)
• Global config ~/.config/opencode/opencode.json has no references field (only $schema, plugin, lsp, mcp, model, model_small, provider)
• Upgraded with brew upgrade; the in-app autoupdater also reports method=brew target=1.18.30

Bug

Every prompt fails immediately with Failed to send prompt. Unexpected server error. Check server logs for details. The request never reaches the provider — it crashes client-side in SystemPrompt.environment, before any model call.

Reproduces on a fresh session, first message, in any directory (confirmed in 4 unrelated dirs across 2 runs), so it is not project- or config-specific.

Log (~/.local/share/opencode/log/opencode.log)

level=ERROR message=failed ref=err_1c01250f
error="TypeError: undefined is not an object (evaluating 'a.name')"
  at resolve (/$bunfs/root/chunk-36bwgd4p.js:2:1659)
  ...
  at SystemPrompt.environment (/$bunfs/root/chunk-y88jw4qv.js:50:13096)
  at SessionPrompt.run
  at SessionRunState.ensureRunning
  at SessionPrompt.loop
  at SessionPrompt.prompt