Transcript Model

thndrs represents a run as typed transcript events rather than one large rendered transcript string. The same event model feeds the live TUI, native terminal scrollback, session persistence, inspection, and export.

Events

User prompts, assistant text, reasoning summaries, tool starts and results, status notices, errors, and turn completion are kept as distinct events.

This lets the renderer show progress without confusing a partial stream with a completed answer, and gives session inspection stable records to summarize.

Persistence

Sessions are append-only JSONL files. They retain replayable transcript content, tool audit metadata, context evidence, and usage totals, but do not persist raw provider payloads or full file contents by default. Secret-looking values are redacted on the diagnostic and inspection paths on a best-effort basis.

Rendering

The TUI renders completed entries into native terminal scrollback and keeps a small live prompt region at the bottom. Detail views can expose bounded additional tool output without turning the transcript into a second viewport.

The renderer has two cooperating lanes.

1. Direct rows own committed transcript history, prompt editing, cursor placement, terminal redraw, and resize replay.
2. A semantic view layer projects app state into prompt, transcript, orientation, and focused-surface data. The iocraft adapter is the only boundary that turns those bounded semantic surfaces into Vec<Row> values.