docs(tui): document thinking effort parity

Author: elkaix

.agents/skills/write-tui/DESIGN.md

@@ -107,7 +107,7 @@ Each hint segment is **key + description**, separated by ` · ` (space-middle-do
 
 - **Character comparisons must go through `printableChar()`** (Kitty protocol), enforced by `printable-key-guard`; function keys use `matchesKey(data, Key.*)`.
 - **Two-stage `Esc`**: when query is non-empty, clear query first (`list.clearQuery()`); only call `onCancel()` when query is empty.
-- `←` / `→` are context-dependent: in components without paging they toggle values (e.g. `/model` thinking on/off); in lists like `choice-picker` they page. **Do not** use `←→` for paging in components that already use it for thinking toggles.
+- `←` / `→` are context-dependent: in components without paging they switch values (e.g. `/model` thinking effort); in lists like `choice-picker` they page. **Do not** use `←→` for paging in components that already use it for thinking effort.
 - **Delete is always letter `D`** (`/provider`, `/plugins`). Letter keys require the list **not** be type-to-search (otherwise input goes into search). Current delete lists are not searchable; if a list needs both search and delete, delete must use a non-printable key.
 
 ## 7. Toggle lists and multi-select
@@ -135,13 +135,13 @@ Rules:
 
 ## 8. Thinking control (`/model` only)
 
-Below the list, show the selected model's thinking tri-state as fixed `[ On ] Off` segments:
+Below the list, show the selected model's thinking effort levels as segments:
 
-- Title: `Thinking  (←→ to switch)` (parenthetical only in `toggle` state); other states show `Thinking` only.
-- `toggle`: `[ On ]  Off` / `On  [ Off ]`, active segment `primary+bold`.
-- `always-on`: `[ Always on ]`.
-- `unsupported`: `[ Off ]` + `unsupported` (textMuted).
-- `←` / `→` flip the draft; commit via `effectiveThinking()` (always-on→true, unsupported→false).
+- Title: `Thinking  (←→ to switch)` when the model offers more than one level; `Thinking` only otherwise.
+- `toggle`: one segment per selectable level — `off` plus the model's `supportEfforts` (fallback `low / med / high`), e.g. `off  low  [ med ]  high`; active segment `primary+bold`, labels via `shortEffortLabel` (`medium` → `med`).
+- `always-on`: the supported levels without an `off` segment.
+- `unsupported`: a single muted `Off (Unsupported)` (textMuted).
+- `←` / `→` move the draft one level within the list (no wraparound); the draft commits on `Enter`. Availability/level helpers live in `utils/thinking-levels.ts` (`effortLevelsForModel`, `coerceEffortForModel`).
 
 ## 9. Multi-field inputs
 

tasks/tui-feature-parity.md

@@ -23,6 +23,7 @@ Legend: ✅ verified, ◻ required evidence, — not applicable, ☐ OpenTUI evi
 | command-plan | `/plan` | `legacy.command.plan` | message flow | ✅ | ◻ | ◻ | — | — | ☐ | ☐ |
 | command-swarm | `/swarm` | `legacy.command.swarm` | message flow | ✅ | ◻ | ◻ | — | — | ☐ | ☐ |
 | command-model | `/model` | `legacy.command.model` | message flow | ✅ | ◻ | ◻ | — | — | ☐ | ☐ |
+| command-effort | `/effort` | `legacy.command.effort` | message flow | ✅ | ◻ | ◻ | — | — | ☐ | ☐ |
 | command-provider | `/provider` | `legacy.command.provider` | message flow | ✅ | ◻ | ◻ | — | — | ☐ | ☐ |
 | command-btw | `/btw` | `legacy.command.btw` | message flow | ✅ | ◻ | ◻ | — | — | ☐ | ☐ |
 | command-help | `/help` | `legacy.command.help` | message flow | ✅ | ◻ | ◻ | — | — | ☐ | ☐ |