[Bug] Raw <parameter> tool-call tags rendered literally in TUI above assistant message #45797

Summary

In the TUI, raw tool-call tags like <parameter name="..."> are occasionally rendered as literal text above the assistant message instead of being parsed/hidden. This happens sporadically while the model makes a tool call.

Expected behavior

Tool-call parameter tags should be consumed by the UI/parser and not appear as visible text in the conversation.

Actual behavior

Sometimes the literal string like <parameter name="foo">...value...</parameter> and stray <parameter> fragments show up above the assistant message in the terminal, corrupting the display. The tools still execute correctly — it is purely a rendering/parsing artifact.

How to reproduce

1. Open the TUI (opencode) and start a session.
2. Ask the model to perform an action that triggers tool calls.
3. Observe the output — intermittently, literal <parameter> tags leak into the rendered message.

Sporadic — does not happen every time, which makes it hard to reproduce on demand. Screenshot will be added when it next reproduces.

Environment

• opencode binary: 1.18.23 (latest)
• Package: opencode-ai@1.18.23
• node: v24.18.0
• Platform: linux (Termux/Android, arm64)
• Terminal: Termux TUI
• Setup: default, no custom plugin involved

Notes

• Root cause appears to be models occasionally emitting raw XML tool-call tags as plain text, combined with the opencode renderer displaying those tags verbatim instead of parsing/executing them.
• Is it possible for the TUI renderer to hide/parse these tags rather than showing them literally? This is purely a display artifact — tools execute fine.