1 files changed, 113 insertions, 17 deletions
diff --git a/src/features/chat/reasoning-effort.ts b/src/features/chat/reasoning-effort.ts
index 2a55089..39e1c5a 100644
--- a/src/features/chat/reasoning-effort.ts
+++ b/src/features/chat/reasoning-effort.ts
@@ -13,11 +13,11 @@ import type { ReasoningEffort } from "@dispatch/transport-contract";
 
 /** The canonical ladder, in ascending thinking-depth order (`[email protected]`). */
 export const REASONING_EFFORT_LEVELS: readonly ReasoningEffort[] = [
-	"low",
-	"medium",
-	"high",
-	"xhigh",
-	"max",
+  "low",
+  "medium",
+  "high",
+  "xhigh",
+  "max",
 ];
 
 /** The server's fallback when nothing is set (the resolution chain's tail). */
@@ -25,7 +25,7 @@ export const DEFAULT_REASONING_EFFORT: ReasoningEffort = "high";
 
 /** Narrow an untrusted string (e.g. a `<select>` value) to the ladder. */
 export function isReasoningEffort(value: string): value is ReasoningEffort {
-	return (REASONING_EFFORT_LEVELS as readonly string[]).includes(value);
+  return (REASONING_EFFORT_LEVELS as readonly string[]).includes(value);
 }
 
 /**
@@ -33,13 +33,13 @@ export function isReasoningEffort(value: string): value is ReasoningEffort {
  * server default when never set (`null` = "default applies", not "off").
  */
 export function effectiveEffort(persisted: ReasoningEffort | null): ReasoningEffort {
-	return persisted ?? DEFAULT_REASONING_EFFORT;
+  return persisted ?? DEFAULT_REASONING_EFFORT;
 }
 
-/** One `<option>` of the selector. */
+/** One `<option>` of the effort ladder. */
 export interface EffortOption {
-	readonly value: ReasoningEffort;
-	readonly label: string;
+  readonly value: ReasoningEffort;
+  readonly label: string;
 }
 
 /**
@@ -47,10 +47,10 @@ export interface EffortOption {
  * `(default)` so a never-set conversation reads "high (default)".
  */
 export function effortOptions(): readonly EffortOption[] {
-	return REASONING_EFFORT_LEVELS.map((level) => ({
-		value: level,
-		label: level === DEFAULT_REASONING_EFFORT ? `${level} (default)` : level,
-	}));
+  return REASONING_EFFORT_LEVELS.map((level) => ({
+    value: level,
+    label: level === DEFAULT_REASONING_EFFORT ? `${level} (default)` : level,
+  }));
 }
 
 // ── Injected port (consumer-defines-port; the composition root adapts the
@@ -58,9 +58,105 @@ export function effortOptions(): readonly EffortOption[] {
 
 /** Outcome of `PUT /conversations/:id/reasoning-effort`. */
 export type ReasoningEffortSaveResult =
-	| { readonly ok: true; readonly reasoningEffort: ReasoningEffort }
-	| { readonly ok: false; readonly error: string };
+  | { readonly ok: true; readonly reasoningEffort: ReasoningEffort }
+  | { readonly ok: false; readonly error: string };
 
 export type SaveReasoningEffort = (
-	level: ReasoningEffort,
+  level: ReasoningEffort,
 ) => Promise<ReasoningEffortSaveResult | null>;
+
+// ── Thinking on/off (a SEPARATE axis from the effort level) ─────────────────
+//
+// Per the umans API (and the user's mental model), "thinking off" is NOT a
+// zero-effort level — it is a distinct "disable extended thinking entirely"
+// signal. The umans route expresses it as `reasoning_effort: "none"`; Dispatch
+// surfaces it as a SEPARATE per-conversation boolean so the effort LEVEL is
+// preserved across an off→on toggle (turning thinking back on restores the
+// previously-chosen depth). The per-conversation selector CONFLATES the two
+// axes into one `<select>` (UX), but the WIRE keeps them separate.
+//
+// ⚠️ BACKEND CONTRACT GAP — see `backend-handoff.md`. The `thinking` endpoint +
+// wire types below are the PROPOSED shape; the backend has NOT shipped them yet.
+// They are defined FE-local (mirroring the shipped `ReasoningEffortResponse` /
+// `SetReasoningEffortRequest` shape) so the FE is built + tested against the
+// target contract. Re-pin + re-mirror once the backend ships them.
+
+/**
+ * Response of `GET /conversations/:id/thinking` (PROPOSED). `thinking` is null
+ * when never set (the server then resolves turns with thinking ON — the
+ * default), `false` when explicitly disabled, `true` when explicitly enabled.
+ */
+export interface ThinkingResponse {
+  readonly conversationId: string;
+  readonly thinking: boolean | null;
+}
+
+/** Body of `PUT /conversations/:id/thinking` (PROPOSED). */
+export interface SetThinkingRequest {
+  readonly thinking: boolean;
+}
+
+/**
+ * The per-conversation selector's value: `"off"` (thinking disabled — the
+ * separate axis) or a reasoning-effort LEVEL. NOT a widened ladder: `"off"` is
+ * not a degree of effort, it is the absence of thinking.
+ */
+export type ThinkingSelection = "off" | ReasoningEffort;
+
+/** One `<option>` of the combined selector (off or a level). */
+export interface SelectionOption {
+  readonly value: ThinkingSelection;
+  readonly label: string;
+}
+
+/**
+ * The selector's options: `"off"` first (the separate disable signal), then the
+ * effort ladder with the server default marked `(default)`. A never-set
+ * conversation (thinking on, effort null) reads "high (default)".
+ */
+export function selectionOptions(): readonly SelectionOption[] {
+  return [{ value: "off", label: "Off" }, ...effortOptions()];
+}
+
+/** Narrow an untrusted `<select>` value to a {@link ThinkingSelection}. */
+export function isThinkingSelection(value: string): value is ThinkingSelection {
+  return value === "off" || isReasoningEffort(value);
+}
+
+/**
+ * The selection the per-conversation selector should show as selected: `"off"`
+ * when thinking is explicitly disabled (`persistedThinking === false`), else the
+ * effective effort level. `persistedThinking === null` (never set) ⇒ thinking
+ * ON (the default) ⇒ the effort level is shown — NOT "off".
+ */
+export function effectiveSelection(
+  persistedEffort: ReasoningEffort | null,
+  persistedThinking: boolean | null,
+): ThinkingSelection {
+  if (persistedThinking === false) return "off";
+  return effectiveEffort(persistedEffort);
+}
+
+// ── Injected port for the combined selector (off OR a level) ─────────────────
+
+/** Outcome of persisting a {@link ThinkingSelection} (one or two PUTs). */
+export type ThinkingSelectionSaveResult =
+  | { readonly ok: true; readonly selection: ThinkingSelection }
+  | { readonly ok: false; readonly error: string };
+
+/**
+ * Persist a thinking selection (consumer-defines-port; the composition root
+ * adapts the store's `PUT .../thinking` + `PUT .../reasoning-effort` to this).
+ * - `"off"` → disable thinking (the separate signal); the effort level is left
+ *   untouched so an off→on toggle restores it.
+ * - a level → set the effort level AND ensure thinking is ON (the level is
+ *   meaningless while thinking is off).
+ */
+export type SaveThinkingSelection = (
+  selection: ThinkingSelection,
+) => Promise<ThinkingSelectionSaveResult | null>;
+
+/** Outcome of `PUT /conversations/:id/thinking`. */
+export type ThinkingSaveResult =
+  | { readonly ok: true; readonly thinking: boolean }
+  | { readonly ok: false; readonly error: string };