diff --git a/README.md b/README.md
index 2f7b856..f7a1fb0 100644
--- a/README.md
+++ b/README.md
@@ -6,6 +6,7 @@ Command-line tools and libraries for interacting with comma devices and the comm
 
 - `comma-connect-api`: Async Rust client for `https://api.commadotai.com`
 - `comma-cli`: CLI application that demonstrates configuration handling and basic API calls
+- `comma-tui`: Lightweight terminal user interface (binary name: `comma`). Early design phase; see `crates/comma-tui/docs/`.
 - `comma-test-utils`: Shared helpers for cucumber/BDD tests (not published)
 
 ## Quick start
diff --git a/crates/comma-tui/Cargo.toml b/crates/comma-tui/Cargo.toml
new file mode 100644
index 0000000..1d626e0
--- /dev/null
+++ b/crates/comma-tui/Cargo.toml
@@ -0,0 +1,33 @@
+[package]
+name = "comma-tui"
+version = "0.1.0"
+edition.workspace = true
+rust-version.workspace = true
+authors.workspace = true
+description = "Terminal user interface for comma devices"
+repository.workspace = true
+homepage.workspace = true
+documentation.workspace = true
+license.workspace = true
+keywords.workspace = true
+categories.workspace = true
+
+[[bin]]
+name = "comma"
+path = "src/main.rs"
+
+[dependencies]
+comma-connect-api.workspace = true
+anyhow.workspace = true
+clap.workspace = true
+serde.workspace = true
+serde_json.workspace = true
+tokio.workspace = true
+tracing.workspace = true
+tracing-subscriber.workspace = true
+
+# TUI (to be added when implementation starts)
+# ratatui = "0.29"
+# crossterm = "0.28"
+
+[dev-dependencies]
diff --git a/crates/comma-tui/README.md b/crates/comma-tui/README.md
new file mode 100644
index 0000000..e2ad7f2
--- /dev/null
+++ b/crates/comma-tui/README.md
@@ -0,0 +1,24 @@
+# comma-tui
+
+Lightweight terminal user interface for interacting with comma devices and the comma connect API.
+
+The binary is named `comma` for convenience.
+
+## Status
+
+Early design phase. No real UI yet. See `docs/` for TUI design notes and decisions.
+
+## Design goals
+
+- Text-only early versions (no video, no thumbnails, no graphics protocols).
+- Tabbed main screen inspired by rustnet.
+- Fully configurable keybindings (Vim-like defaults).
+- Separate config from `comma-cli`, but respects the same environment variables.
+- Dongle switcher + routes + upload queue as the first useful views.
+
+## Building
+
+```bash
+cargo build -p comma-tui
+./target/debug/comma
+```
diff --git a/crates/comma-tui/docs/DESIGN.md b/crates/comma-tui/docs/DESIGN.md
new file mode 100644
index 0000000..805e44e
--- /dev/null
+++ b/crates/comma-tui/docs/DESIGN.md
@@ -0,0 +1,124 @@
+# TUI Design Notes
+
+These are working notes on the intended look, feel, and behaviour of the `comma` TUI.
+They are not formal architecture decision records (ADRs); they capture use-case and
+interaction design thinking so we can implement deliberately.
+
+Related: see the individual notes in this directory.
+
+## Core principles
+
+- **Lightweight first.** Early versions are pure text. No video playback, no
+  thumbnails, no half-block rendering, no graphics protocols.
+- **Useful before pretty.** Prioritise routes list, upload queue, device overview,
+  and dongle switching. Visual flourishes (coloured route markers, etc.) come later.
+- **Fixed, source-defined keybindings.** Keybindings are not user-configurable.
+  They live in one place in the source code (with associated display strings).
+  Defaults are Vim-like, with support for modifiers and multiple keys per action.
+- **Separate but compatible config.** The TUI has its own config file (TOML via
+  confy, same strategy as `comma-cli`). Dongle ID and token can live there, but
+  environment variables (`COMMA_TOKEN`, `COMMA_DONGLE`) are preferred and shared
+  with `comma-cli`. CLI flags override both.
+
+## Main screen layout (inspired by rustnet)
+
+```
+┌───────────────────────────────────────────────────────┐
+│  Routes   Queue   Device    Devices   Help            │  ← tab bar
+├───────────────────────────────────────────────────────┤
+│                                                       │
+│  (active tab content)                                 │
+│                                                       │
+│                                                       │
+├───────────────────────────────────────────────────────┤
+│  j/k: move   space: select   q: quit   ? : help       │  ← status / key hints
+└───────────────────────────────────────────────────────┘
+```
+
+- Top line: list of tabs, active tab highlighted.
+- Bottom line: context-sensitive keyboard shortcuts currently available
+  (subset of bindings, ranked by importance, limited by terminal width).
+- Rightmost tab is always **Help**, which lists all keybindings (including
+  alternatives and modifiers) generated from the source-defined binding table.
+
+## Tabs (initial set)
+
+1. **Routes** — list of routes for the active dongle (metadata only).
+2. **Queue** — upload queue for the active dongle.
+3. **Device** — overview of the active dongle.
+4. **Devices** — switch the active dongle. Lists all devices the user can access
+   (owned + shared). Only one is active at a time; other tabs show data for it.
+5. **Help** — full keybinding and command overview (generated from source).
+
+## Dongle selection
+
+- On startup, select the dongle from (in order): `--dongle` / `-d` CLI flag,
+  `COMMA_DONGLE` environment variable, last-selected dongle stored in the TUI
+  config, or prompt / first available.
+- The Devices tab lets the user change the active dongle at runtime.
+  The choice is persisted to the TUI config.
+- All other data tabs operate on the currently selected dongle.
+- Users who want to ignore a persisted or environment dongle temporarily can
+  use `env -u COMMA_DONGLE comma` (or pass `--dongle`).
+
+## Configuration
+
+Own config file managed by `confy` (TOML, platform-standard location, same
+strategy as `comma-cli`; typically `~/.config/comma-tui/config.toml` on Linux).
+
+Example sketch:
+
+```toml
+default_dongle = "0123456789abcdef"
+# token = "..."   # prefer env var
+last_dongle = "0123456789abcdef"   # written by the TUI on dongle switch
+```
+
+Keybindings are **not** in the config; they are defined in source code.
+
+## Keybindings
+
+- Defined in a single place in the source code.
+- Each binding has an associated display string (e.g. `space`, `enter`,
+  `ctrl-f`) used by the bottom bar and Help tab. Changing a binding or its
+  display string requires no other edits.
+- Support for modifier keys (e.g. `Ctrl-F` / `Ctrl-B` for page up/down).
+- Multiple keys may be bound to the same action (e.g. both `j`/`k` and arrow
+  keys for movement).
+- Help tab lists all bindings for each action.
+- Bottom bar shows a ranked subset (by importance), truncated as needed for
+  terminal width. The set of hints is context-sensitive per tab (Routes has
+  upload actions, Queue has cancel, Device has alias editing, etc.).
+
+## Feature parity with the CLI
+
+The TUI should offer roughly the same interactive capabilities as the CLI
+(routes listing, upload queue management, requesting uploads of cameras/logs/
+routes/recent-routes, device alias changes, etc.).
+
+- CLI remains the right tool for scripting, one-off commands, and raw JSON
+  output.
+- TUI translates API responses into human-friendly interactive views.
+- Reusable helper logic currently living in `comma-cli/src/main.rs` (the
+  various `cmd_*` functions) should be extracted into a shared module that
+  both the CLI and TUI can use.
+
+## Non-goals for early versions
+
+- Rendering any frames from route video footage.
+- Thumbnails or coloured route icons (possible later, e.g. time-of-day colour).
+- Graphics protocol support (Kitty, Sixel, iTerm2) or half-block video.
+- Replacing the web UI’s media viewing experience.
+- User-configurable keybindings.
+
+## Resolved questions
+
+- **Config format and location:** TOML via `confy`, same strategy as
+  `comma-cli`.
+- **Bottom bar:** Fully dynamic and context-sensitive. Number of shown hints
+  depends on terminal width and an importance ranking of the bindings.
+- **Upload-request workflow:** Offer more or less the same features in CLI
+  and TUI. Extract shared helpers from the CLI.
+- **Persistence of last-selected dongle:** Written to the TUI config.
+  Overridden by environment variable or CLI flag. Temporary override via
+  `env -u COMMA_DONGLE comma`.
diff --git a/crates/comma-tui/docs/TDR-001-lightweight-text-only.md b/crates/comma-tui/docs/TDR-001-lightweight-text-only.md
new file mode 100644
index 0000000..34cc9fa
--- /dev/null
+++ b/crates/comma-tui/docs/TDR-001-lightweight-text-only.md
@@ -0,0 +1,30 @@
+# TDR-001: Lightweight text-only early versions
+
+## Context
+
+The comma web UI shows route video. Terminal video playback is possible via
+graphics protocols (Kitty, iTerm2, Sixel) or unicode half-blocks, but:
+
+- Stock Alacritty supports none of the graphics protocols.
+- Half-block video is blocky and bandwidth-heavy.
+- The primary value of a TUI for many users is metadata, queue management,
+  and quick navigation, not media playback.
+
+## Decision
+
+Early versions of `comma` (the TUI) will contain **no** rendering of video
+footage, not even still thumbnails or coloured route markers.
+
+Routes are listed as plain text lines derived from metadata.
+
+## Consequences
+
+- Faster to implement and ship useful functionality.
+- Works identically in Alacritty, over SSH, and in any truecolor terminal.
+- Leaves the door open for optional visual enhancements later (time-of-day
+  colour blocks, half-blocks, or protocol-based images) without blocking
+  the core experience.
+
+## Status
+
+Accepted (2026-10-18)
diff --git a/crates/comma-tui/docs/TDR-002-tabbed-layout.md b/crates/comma-tui/docs/TDR-002-tabbed-layout.md
new file mode 100644
index 0000000..7a6f948
--- /dev/null
+++ b/crates/comma-tui/docs/TDR-002-tabbed-layout.md
@@ -0,0 +1,31 @@
+# TDR-002: Tabbed layout inspired by rustnet
+
+## Context
+
+We want a clear, keyboard-driven main screen. Two reference TUIs are rustnet
+(ratatui, tabbed) and btop (more dashboard-like). The preference is closer to
+rustnet.
+
+## Decision
+
+The main screen is tabbed:
+
+- Top bar lists tabs and highlights the active one.
+- Bottom bar shows currently relevant keybindings (ranked subset, limited by
+  terminal width; generated from the source-defined binding table).
+- Rightmost tab is always Help and lists all bindings (including alternatives
+  and modifiers) generated from the same source table.
+
+Initial tabs: Routes, Queue, Device, Devices, Help.
+
+## Consequences
+
+- Familiar mental model for users of rustnet-style tools.
+- Help and bottom bar stay automatically consistent with the code-defined
+  bindings.
+- Easy to add further tabs later without redesigning the shell.
+- Bottom bar can be context-sensitive per tab without extra configuration.
+
+## Status
+
+Accepted (2026-10-19)
diff --git a/crates/comma-tui/docs/TDR-003-config-and-env.md b/crates/comma-tui/docs/TDR-003-config-and-env.md
new file mode 100644
index 0000000..9ba03cd
--- /dev/null
+++ b/crates/comma-tui/docs/TDR-003-config-and-env.md
@@ -0,0 +1,38 @@
+# TDR-003: Separate config with shared environment variables
+
+## Context
+
+`comma-cli` already stores a default dongle ID and token via confy
+(`~/.config/comma-cli/config.toml`) and prefers `COMMA_TOKEN` /
+`COMMA_DONGLE` environment variables.
+
+The TUI has different needs (persistence of last-selected dongle, possibly
+other UI state) and different usage patterns. Keybindings are deliberately
+not part of the config.
+
+## Decision
+
+- The TUI has its **own** config file, managed by `confy` (TOML, same
+  strategy and platform-standard locations as `comma-cli`).
+- It may store a default dongle ID, token, and the last-selected dongle.
+- It **must** honour the same environment variables (`COMMA_TOKEN`,
+  `COMMA_DONGLE`) that the CLI uses.
+- CLI flags (`--dongle`, `--token`) override both config and environment.
+- Keybindings are **not** stored in the config; they are defined in source
+  code (see TDR-004).
+
+Duplication of dongle/token is acceptable; environment variables remain the
+preferred shared mechanism.
+
+## Consequences
+
+- Users can keep secrets out of config files via environment variables.
+- TUI-specific state (last dongle) does not pollute the CLI config.
+- Startup selection order is well-defined: CLI flag > env > config (including
+  last-selected) > fallback.
+- Temporary override of a persisted or environment dongle is possible with
+  `env -u COMMA_DONGLE comma` or an explicit `--dongle` flag.
+
+## Status
+
+Accepted (2026-10-19)
diff --git a/crates/comma-tui/docs/TDR-004-keybindings.md b/crates/comma-tui/docs/TDR-004-keybindings.md
new file mode 100644
index 0000000..38e99bc
--- /dev/null
+++ b/crates/comma-tui/docs/TDR-004-keybindings.md
@@ -0,0 +1,40 @@
+# TDR-004: Fixed source-defined keybindings (not user-configurable)
+
+## Context
+
+Earlier design considered fully user-configurable keybindings (to accommodate
+layouts such as Colemak-DH). After further thought, the complexity of a
+configurable binding system (config parsing, validation, dynamic Help and
+status-bar generation from user input, conflict handling) is not worth the
+benefit for a focused TUI. A single source-of-truth in code is simpler,
+easier to test, and still allows the display strings to stay in sync with
+the actual keys.
+
+## Decision
+
+- Keybindings are **not** user-configurable.
+- All bindings live in one place in the source code.
+- Each binding carries its own display string (e.g. `space`, `enter`,
+  `ctrl-f`, `up`). The bottom bar and Help tab are generated from this table,
+  so changing a key or its label requires no other edits.
+- Modifier keys are supported (examples: `Ctrl-F` / `Ctrl-B` for page
+  up/down).
+- Multiple keys may be bound to the same action (e.g. both `j`/`k` and the
+  arrow keys for vertical movement).
+- The Help tab lists every binding for each action.
+- The bottom bar shows a ranked subset of the currently relevant bindings
+  (importance rank + available terminal width). The set of hints is
+  context-sensitive per tab.
+
+## Consequences
+
+- Much less implementation and testing complexity.
+- Help and status bar stay automatically consistent with the code.
+- Users who strongly prefer a different layout must either live with the
+  defaults or fork/patch the binding table (acceptable trade-off).
+- Easy to add alternative keys (arrows, etc.) without user configuration.
+
+## Status
+
+Accepted (2026-10-19) — supersedes the previous “fully configurable”
+decision.
diff --git a/crates/comma-tui/docs/TDR-005-dongle-switcher.md b/crates/comma-tui/docs/TDR-005-dongle-switcher.md
new file mode 100644
index 0000000..23be58e
--- /dev/null
+++ b/crates/comma-tui/docs/TDR-005-dongle-switcher.md
@@ -0,0 +1,32 @@
+# TDR-005: Dongle switcher tab (Devices)
+
+## Context
+
+A user may own multiple devices or have been granted read access to devices
+owned by others (via useradmin.comma.ai). The TUI needs a clear way to choose
+which dongle’s data is shown in the other tabs.
+
+## Decision
+
+- There is a dedicated **Devices** tab that lists all accessible devices.
+- Exactly one dongle is active at a time.
+- Other tabs (Routes, Queue, Device, …) always operate on the active dongle.
+- On startup the active dongle is chosen by: CLI `--dongle`/`-d` >
+  `COMMA_DONGLE` env > last-selected dongle stored in the TUI config >
+  first available (or prompt).
+- Changing the selection in the Devices tab updates the active dongle for the
+  rest of the session **and** persists the choice to the TUI config.
+- Users can temporarily ignore the persisted or environment value with
+  `env -u COMMA_DONGLE comma` or by passing `--dongle`.
+
+## Consequences
+
+- Clear model for multi-device users.
+- CLI and environment overrides are honoured, matching `comma-cli` behaviour.
+- Avoids the need to restart the TUI when switching devices.
+- Last-selected dongle survives across runs without requiring the user to
+  edit the config by hand.
+
+## Status
+
+Accepted (2026-10-19)
diff --git a/crates/comma-tui/docs/TDR-006-feature-parity.md b/crates/comma-tui/docs/TDR-006-feature-parity.md
new file mode 100644
index 0000000..1f1d915
--- /dev/null
+++ b/crates/comma-tui/docs/TDR-006-feature-parity.md
@@ -0,0 +1,35 @@
+# TDR-006: Feature parity with CLI and shared helpers
+
+## Context
+
+The CLI already implements a useful set of operations (route listing, upload
+queue inspection and cancellation, requesting uploads of individual file
+kinds, whole routes, and recent routes, device information, etc.). The TUI
+should not reinvent these; it should expose roughly the same capabilities in
+an interactive form.
+
+## Decision
+
+- The TUI will offer more or less the same interactive features as the CLI.
+- The CLI remains the appropriate tool for scripting, one-off commands, and
+  obtaining raw JSON API responses.
+- The TUI translates those responses into human-friendly interactive views.
+- Reusable logic currently living in `comma-cli/src/main.rs` (the various
+  `cmd_*` helper functions) should be extracted into a shared module that
+  both the CLI and the TUI can depend on.
+- As features are added, add any necessary new helpers in the shared module
+  so that CLI would be able to readily use them and thus speed-up the
+  reimplementation of a TUI feature or vice versa (reimplementation of a new
+  CLI feature in the TUI).
+
+## Consequences
+
+- Avoids divergent behaviour between CLI and TUI.
+- Keeps the TUI focused on presentation and interaction while reusing
+  proven request/response handling.
+- Slightly more up-front refactoring of the CLI, but pays off as both the
+  CLI and TUI grows.
+
+## Status
+
+Accepted (2026-10-19)
diff --git a/crates/comma-tui/src/main.rs b/crates/comma-tui/src/main.rs
new file mode 100644
index 0000000..01e5ed7
--- /dev/null
+++ b/crates/comma-tui/src/main.rs
@@ -0,0 +1,9 @@
+//! Placeholder entry point for the `comma` TUI.
+//!
+//! This binary will grow into a lightweight terminal UI for comma devices,
+//! focusing first on text-based metadata views (routes, upload queue, devices).
+
+fn main() {
+    println!("comma TUI — coming soon");
+    println!("See crates/comma-tui/docs/ for design notes.");
+}