Feature: In-session text search (Cmd+F / Ctrl+F) #15602

Summary

Add a simple in-session text search (similar to Cmd+F / Ctrl+F in a browser or terminal) to find text within the current conversation.

Problem

During long coding sessions, conversations accumulate significant context — file paths, error messages, decisions, variable names, etc. There is currently no way to search through the visible conversation history without leaving OpenCode.

Current workarounds

None of these let you stay in the TUI and quickly jump to a match.

Proposed solution

Phase 1 — Simple find (low effort, high value)

A basic incremental text search over the rendered conversation, similar to less -i or terminal emulator find:

• Trigger: A keybind (e.g., <leader>/ or <leader>f, configurable via tui.json)
• Behavior: Opens a small search input overlay at the top or bottom of the message area
• Features:
  • Case-insensitive by default, case-sensitive when the query contains uppercase (smart-case)
  • Enter / Shift+Enter (or n / N) to jump to next/previous match
  • Matches highlighted in the scroll area
  • Escape to dismiss
• Scope: Searches all visible message text in the current session (user messages, assistant responses, tool output)

Phase 2 — Enhanced search (future)

If Phase 1 proves useful, potential enhancements could include:

• Regex support
• Filtering by message role (user / assistant / tool)
• Cross-session search via /sessions list
• Search within collapsed tool output

Context

This came up during a long multi-hour coding session where I needed to find earlier references to a specific topic. The conversation had hundreds of messages and the only option was to /export and search externally, which was disruptive.

Even a minimal Phase 1 implementation would be a significant quality-of-life improvement for longer sessions.