## Summary
- add `Feature::TerminalVisualizationInstructions` as
`UnderDevelopment`, disabled by default
- keep terminal visualization instructions inside the TUI package
- append them to existing developer instructions for TUI start, resume,
and fork flows only when enabled
- intentionally do not apply them to `codex exec`
## Rollout
Control behavior is unchanged. TUI dogfooders can enable
`terminal_visualization_instructions`; no default user receives the new
terminal-specific instructions.
The shared visualization-selection rule is supplied separately through
the `codex_proxy_model_3` Statsig layer for every target Codex model
slug in the gated cohort. This TUI feature determines how to render an
appropriate visualization on the terminal surface; the model-layer
treatment determines when to use one.
## Validation
- `cargo test -p codex-tui
terminal_visualization_instructions_are_gated_for_all_tui_thread_flows
--lib`
- `cargo test -p codex-features --lib`
- `cargo fmt --all -- --check`
- `git diff --check`
- GPT-5.4 and GPT-5.5 real prompt-pipeline smoke tests: both visualized
the positive mapping case, abstained on the negative route case, and
passed exact prompt-stack verification on CLI and App
- refreshed onto current `main` with a clean merge and reran the focused
validation
The full 53-probe all-model treatment comparison and requested
production coding evals remain rollout gates before broadening beyond
the initial employee cohort.
This PR remains open for normal human review.
vie-oai