feat(web): drop "none" from the offered thinking levels (#34)

Co-authored-by: Alice <alice@prismshadow.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

packages/web/src/features/chat/chat-input.tsx

@@ -64,7 +64,7 @@ import { ProviderLogo } from "../../components/ui/provider-logo";
 import { hasConfiguredKey, sameModelRef, visibleChatModels } from "../models/model-grouping";
 import { filterAgents, matchMention, splitLeadingMention } from "./agent-mentions";
 import { matchSlash, removeSlashToken } from "./slash-token";
-import { THINKING_LEVELS, thinkingLevelLabel } from "./thinking-level";
+import { SELECTABLE_THINKING_LEVELS, thinkingLevelLabel } from "./thinking-level";
 import {
   BOOK_ICON,
   buildSkillsMessage,
@@ -393,8 +393,10 @@ const SPARK_ICON = "M12 3l1.9 5.1L19 10l-5.1 1.9L12 17l-1.9-5.1L5 10l5.1-1.9L12
  * level straight through to the Agent settings — llmConfig is assembled once per session, so
  * the level applies to the session created on first send and becomes the Agent's new default
  * (switch-becomes-default). Per review: a title bar names the control, and the menu lists
- * exactly the five levels with short names only (no descriptions, no "default" row) — an
- * Agent without an explicit override shows an em dash until a level is picked.
+ * the selectable levels with short names only (no descriptions, no "default" row, and no
+ * "none" — many models cannot disable thinking); an Agent without an explicit override shows
+ * an em dash until a level is picked, and a stored legacy "none" still displays via the
+ * label table (just never offered).
  */
 function ThinkingLevelSelect({
   value,
@@ -449,7 +451,7 @@ function ThinkingLevelSelect({
       <div className="border-b border-gray-100 px-3 pb-1.5 pt-0.5 text-xs font-semibold text-gray-500 dark:border-gray-800 dark:text-gray-400">
         {S.chat.thinkingLevel}
       </div>
-      {THINKING_LEVELS.map((level) => (
+      {SELECTABLE_THINKING_LEVELS.map((level) => (
         <button
           key={level}
           type="button"

packages/web/src/features/chat/thinking-level.ts

@@ -5,18 +5,29 @@
  * it shows the selected Agent's current level and writes a picked level straight through
  * to the Agent config, so the session created on first send — which reads systemConfig
  * fresh — runs with it, and it becomes the Agent's new default (switch-becomes-default).
- * Per review: the menu lists exactly the five levels with short names only (no
- * descriptions, no "default" row) under a title bar naming the control.
+ * Per review: the menu lists the levels with short names only (no descriptions, no
+ * "default" row) under a title bar naming the control — and it does **not** offer "none"
+ * (many models cannot disable thinking): "none" stays a valid stored/wire value, so a
+ * legacy config or session that carries it still displays via the label table below.
  */
 
-/** The five levels, in menu order (mirrors core's ThinkingLevelName). */
+/** All five stored/wire levels, for display lookup (mirrors core's ThinkingLevelName). */
 export const THINKING_LEVELS = ["none", "low", "medium", "high", "xhigh"] as const;
 
+/**
+ * The levels the picker offers, in menu order: "none" is deliberately excluded (many models
+ * don't support disabling thinking) — it can still be displayed (a stored legacy value) but
+ * never picked.
+ */
+export const SELECTABLE_THINKING_LEVELS = ["low", "medium", "high", "xhigh"] as const;
+
 /**
  * Short display label for a level from the localized name table (S.chat.thinkingLevelNames).
- * Returns null for anything outside the five levels — including "" (an Agent without an
- * explicit override) and session_meta's "default" — so callers can render a placeholder on
- * the trigger and hide the session read-only tag instead of showing a raw internal value.
+ * Covers all five stored levels including "none" (so a legacy value displays sanely instead
+ * of being rewritten or hidden). Returns null for anything else — including "" (an Agent
+ * without an explicit override) and session_meta's "default" — so callers can render a
+ * placeholder on the trigger and hide the session read-only tag instead of showing a raw
+ * internal value.
  */
 export function thinkingLevelLabel(
   names: Readonly<Record<string, string>>,
@@ -26,3 +37,46 @@ export function thinkingLevelLabel(
     ? (names[level] ?? level)
     : null;
 }
+
+/** One dropdown row of the agent-settings thinking-level menu (shape of OptionMenuChoice<string>). */
+export interface ThinkingLevelOptionRow {
+  value: string;
+  /** Compact text on the trigger button ("" renders the localized default tag). */
+  triggerLabel: string;
+  /** Panel row title. */
+  label: string;
+  /** Panel row description. */
+  description: string;
+}
+
+/**
+ * Assembles the agent-settings thinking-level dropdown rows from the dictionary's
+ * [value, description] pairs (which no longer include `none`). Backward compatibility:
+ * when the **persisted** config already stores `none` (a legacy value), a display-only
+ * row for it is appended — the trigger shows the real stored state instead of "—" and
+ * nothing is silently rewritten. Gating on the persisted value (not the local edit
+ * state) means a misclick onto another tier keeps the row until the change is actually
+ * saved, so the user can always click back to the value still stored on disk.
+ */
+export function thinkingLevelOptionsFor(
+  options: ReadonlyArray<readonly [string, string]>,
+  defaultTag: string,
+  noneKeptDescription: string,
+  storedLevel: string | undefined,
+): ThinkingLevelOptionRow[] {
+  const rows = options.map(([value, description]) => ({
+    value,
+    triggerLabel: value || defaultTag,
+    label: value || defaultTag,
+    description,
+  }));
+  if (storedLevel === "none") {
+    rows.push({
+      value: "none",
+      triggerLabel: "none",
+      label: "none",
+      description: noneKeptDescription,
+    });
+  }
+  return rows;
+}