---
name: tmt-tui
description: Verify the internal TUI markup crate (`rust/crates/tmt-tui`) - XML admission, utilities, geometry, paint and components - and the Squad board parity baseline. Load when changing tmt-tui or board output. Owner - tmt-ux.
---

# Internal TUI markup (`tmt-tui`)

## Drawing boundary

Squad consumes drawing primitives through `tmt-tui`. The native architecture
test's `architecture/board_widgets.rs` checks Squad's production module tree
with the existing syn collector, including qualified, imported, aliased and
macro-token widget paths. Widget traits and state are infrastructure; unrelated
CLI/TOML tables and test-only code remain outside the primitive prohibition.

The guard's exception list is empty: any raw widget in Squad's production tree
fails, and an exception needs a documented boundary decision. The surface map
belongs to [tmt-ops-dev](../tmt-ops-dev/SKILL.md).

Run `CARGO_BUILD_JOBS=2 cargo test --locked -p tmt-cli --test architecture`
from `rust/`. It includes a clean source-tree control and a seeded raw-widget
failure through real module discovery. Keep the frozen parity gate in the
development reference below; unexplained differences block handoff.

## Terminal screen

`components::terminal` shows another program's screen: `Screen` takes bytes and a size and
publishes a `Frame` of cells (colours, attributes, wide characters, cursor, input modes); `key_bytes`,
`paste_bytes`, `wheel_bytes` and `is_leave` (Ctrl-\) are the bytes a key, a paste or a wheel turn
sends back. It parses with `vt100` at the workspace pin (the parser that formats a built-in host's
snapshot), keeps no scrollback and does no I/O, and it knows nothing of the stream that carries the
bytes or of `tmt-pty-protocol`.

## References

- [references/pipeline-and-components.md](references/pipeline-and-components.md): admission, binding, geometry, paint and component rules.
- [references/development.md](references/development.md): build, test and verification commands moved from DEVELOPMENT.md.

## Admission rules

- Squad is the only reviewed consumer. A new consumer, a new dependency, an
  app-neutral API change or any Squad term in the crate still needs tmt-lead review.
  The architecture guard permits
  XML parsing, borrowed JSON, shared style, private Taffy geometry and Ratatui
  buffer painting; never core, adapters, CLI or extension behavior.
- The leaf acquires nothing: no terminal, clock, settings persistence, markdown or
  provider data. Applications own data, effects, item cursors and terminal
  lifecycle.
- Components implement the
  [full-screen interaction guideline](../../../design/cli-style.md#full-screen-interaction);
  application-owned descriptions and effective bindings supply their text.
- Tokens use `tmt-cli-style::theme::Role`. No palette is resolved or copied here.