feat(agents): per-model reasoning effort level

Add a per-model/key reasoning effort setting to agent definitions,
surfaced and editable in the Agent Settings page and displayed at a
glance in the model selector views.

- core: single source of truth for effort levels (REASONING_EFFORTS,
  DEFAULT_REASONING_EFFORT='high', labels, isReasoningEffort guard);
  add 'xhigh' level; AgentModelEntry.effort; xhigh budget=24000 for
  classic-thinking Claude; default floor 'high'. Persist/parse effort
  in the agent TOML loader.
- api: thread effort through the fallback chain with per-model -> per-tab
  -> default precedence; validate /chat + agentModels effort from the
  canonical list.
- frontend: effort <select> per model row in AgentBuilder; effort badges
  in ModelSelector (agent + subagent chains); Thinking dropdown sourced
  from canonical list; per-tab default raised to 'high'.
- tests: +15 (loader round-trip, agent xhigh budget, canonical list +
  guard, api precedence, route validation).

5 files changed, 82 insertions, 32 deletions

diff --git a/packages/frontend/src/App.svelte b/packages/frontend/src/App.svelte
index eaa28e8..3f1c500 100644
--- a/packages/frontend/src/App.svelte
+++ b/packages/frontend/src/App.svelte
@@ -1,4 +1,5 @@
 <script lang="ts">
+import { DEFAULT_REASONING_EFFORT } from "@dispatch/core/src/types/index.js";
 import { onMount } from "svelte";
 import AgentBuilder from "./lib/components/AgentBuilder.svelte";
 import ChatInput from "./lib/components/ChatInput.svelte";
@@ -141,20 +142,14 @@ onMount(() => {
 				apiBase={config.apiBase}
 				activeKeyId={tabStore.activeTab?.keyId ?? null}
 				activeModelId={tabStore.activeTab?.modelId ?? null}
-				reasoningEffort={tabStore.activeTab?.reasoningEffort ?? "max"}
+				reasoningEffort={tabStore.activeTab?.reasoningEffort ?? DEFAULT_REASONING_EFFORT}
 				activeAgentSlug={tabStore.activeTab?.agentSlug ?? null}
 				activeTabParentId={tabStore.activeTab?.parentTabId ?? null}
 				activeAgentModels={tabStore.activeTab?.agentModels ?? null}
 				workingDirectory={tabStore.activeTab?.workingDirectory ?? null}
 				onKeyChange={(keyId) => tabStore.setKey(keyId)}
 				onModelChange={(keyId, modelId) => tabStore.changeModel(keyId, modelId)}
-				onReasoningChange={(effort) => {
-					const tab = tabStore.activeTab;
-					if (tab) {
-						// Update reasoning effort for active tab
-						tabStore.tabs.find(t => t.id === tab.id)!.reasoningEffort = effort;
-					}
-				}}
+				onReasoningChange={(effort) => tabStore.setReasoningEffort(effort)}
 				onAgentChange={(agent) => tabStore.setAgent(agent)}
 				onWorkingDirectoryChange={(dir) => tabStore.setWorkingDirectory(dir)}
 			onAddKey={() => { showAddKeyModal = true; addKeyId = ""; addKeyProvider = "anthropic"; addKeyError = null; }}
diff --git a/packages/frontend/src/lib/components/AgentBuilder.svelte b/packages/frontend/src/lib/components/AgentBuilder.svelte
index d8ae530..bbdb83c 100644
--- a/packages/frontend/src/lib/components/AgentBuilder.svelte
+++ b/packages/frontend/src/lib/components/AgentBuilder.svelte
@@ -4,6 +4,11 @@ const modelCache = new Map();
 </script>
 
 <script lang="ts">
+	import {
+		DEFAULT_REASONING_EFFORT,
+		REASONING_EFFORTS,
+		REASONING_EFFORT_LABELS,
+	} from "@dispatch/core/src/types/index.js";
 	import { config } from "../config.js";
 	import { router } from "../router.svelte.js";
 	import type { KeyInfo } from "../types.js";
@@ -13,6 +18,7 @@ const modelCache = new Map();
 	interface AgentModelEntry {
 		key_id: string;
 		model_id: string;
+		effort?: string;
 	}
 
 	interface AgentDefinition {
@@ -173,6 +179,10 @@ const modelCache = new Map();
 		formModels = formModels.filter((_, idx) => idx !== i);
 	}
 
+	function setEffortEntry(i: number, effort: string) {
+		formModels = formModels.map((m, idx) => (idx === i ? { ...m, effort } : m));
+	}
+
 	async function openKeyModal(i: number) {
 		modelModalIndex = i;
 		modelModalType = "key";
@@ -546,6 +556,16 @@ const modelCache = new Map();
 								>
 									{entry.model_id || "Select Model"}
 								</button>
+								<select
+									class="select select-bordered select-sm shrink-0 w-28"
+									title="Reasoning effort for this model"
+									value={entry.effort ?? DEFAULT_REASONING_EFFORT}
+									onchange={(e) => setEffortEntry(i, e.currentTarget.value)}
+								>
+									{#each REASONING_EFFORTS as effort}
+										<option value={effort}>{REASONING_EFFORT_LABELS[effort]}</option>
+									{/each}
+								</select>
 								<button
 									type="button"
 									class="btn btn-sm btn-ghost text-error"
diff --git a/packages/frontend/src/lib/components/ModelSelector.svelte b/packages/frontend/src/lib/components/ModelSelector.svelte
index a752f5d..c328511 100644
--- a/packages/frontend/src/lib/components/ModelSelector.svelte
+++ b/packages/frontend/src/lib/components/ModelSelector.svelte
@@ -3,6 +3,12 @@ const modelCache = new Map<string, string[]>();
 </script>
 
 <script lang="ts">
+	import {
+		DEFAULT_REASONING_EFFORT,
+		isReasoningEffort,
+		REASONING_EFFORTS,
+		REASONING_EFFORT_LABELS,
+	} from "@dispatch/core/src/types/index.js";
 	import type { KeyInfo } from "../types.js";
 	import { config } from "../config.js";
 	import { router } from "../router.svelte.js";
@@ -14,7 +20,7 @@ const modelCache = new Map<string, string[]>();
 		description: string;
 		skills: string[];
 		tools: string[];
-		models: Array<{ key_id: string; model_id: string }>;
+		models: Array<{ key_id: string; model_id: string; effort?: string }>;
 		cwd?: string;
 		is_subagent?: boolean;
 	}
@@ -30,6 +36,15 @@ const modelCache = new Map<string, string[]>();
 		};
 	}
 
+	/**
+	 * Human-readable effort label for a (possibly-unset / arbitrary) effort
+	 * string. Falls back to the default level's label when unset/invalid so the
+	 * displayed badge always reflects what will actually be used.
+	 */
+	function effortLabel(effort: string | undefined): string {
+		return REASONING_EFFORT_LABELS[isReasoningEffort(effort) ? effort : DEFAULT_REASONING_EFFORT];
+	}
+
 	const {
 		keys = [],
 		activeKeyId = null,
@@ -37,7 +52,7 @@ const modelCache = new Map<string, string[]>();
 		reasoningEffort = "max",
 		activeAgentSlug = null,
 		activeTabParentId = null as string | null,
-		activeAgentModels = null as Array<{ key_id: string; model_id: string }> | null,
+		activeAgentModels = null as Array<{ key_id: string; model_id: string; effort?: string }> | null,
 		workingDirectory = null,
 		onKeyChange,
 		onModelChange,
@@ -51,7 +66,7 @@ const modelCache = new Map<string, string[]>();
 		reasoningEffort?: string;
 		activeAgentSlug?: string | null;
 		activeTabParentId?: string | null;
-		activeAgentModels?: Array<{ key_id: string; model_id: string }> | null;
+		activeAgentModels?: Array<{ key_id: string; model_id: string; effort?: string }> | null;
 		workingDirectory?: string | null;
 		onKeyChange: (keyId: string) => void;
 		onModelChange: (keyId: string, modelId: string) => void;
@@ -264,11 +279,9 @@ const modelCache = new Map<string, string[]>();
 					value={reasoningEffort}
 					onchange={(e) => onReasoningChange(e.currentTarget.value)}
 				>
-					<option value="none">Off</option>
-					<option value="low">Low</option>
-					<option value="medium">Medium</option>
-					<option value="high">High</option>
-					<option value="max">Max</option>
+					{#each REASONING_EFFORTS as effort}
+						<option value={effort}>{REASONING_EFFORT_LABELS[effort]}</option>
+					{/each}
 				</select>
 			</div>
 		{/if}
@@ -312,8 +325,9 @@ const modelCache = new Map<string, string[]>();
 					</div>
 					<div class="mt-1 flex flex-col gap-0.5">
 						{#each subModels as m, i}
-							<div class="text-xs font-mono truncate {i === displayIdx ? 'opacity-100 font-semibold' : 'opacity-50'}">
-								{i + 1}. {m.key_id} / {m.model_id}
+							<div class="text-xs font-mono truncate flex items-center gap-1 {i === displayIdx ? 'opacity-100 font-semibold' : 'opacity-50'}">
+								<span class="truncate">{i + 1}. {m.key_id} / {m.model_id}</span>
+								<span class="badge badge-xs badge-ghost shrink-0">{effortLabel(m.effort)}</span>
 							</div>
 						{/each}
 					</div>
@@ -373,8 +387,9 @@ const modelCache = new Map<string, string[]>();
 							{@const displayIdx = sliderDragging !== null ? sliderDragging : (currentIdx >= 0 ? currentIdx : 0)}
 							{@const displayModel = agent.models[displayIdx]}
 							<div class="mt-2 pt-2 border-t border-primary-content/20">
-								<div class="text-xs font-semibold mb-1 truncate">
-									{displayModel ? `${displayModel.key_id} / ${displayModel.model_id}` : `${activeKeyId} / ${activeModelId}`}
+								<div class="text-xs font-semibold mb-1 truncate flex items-center gap-1">
+									<span class="truncate">{displayModel ? `${displayModel.key_id} / ${displayModel.model_id}` : `${activeKeyId} / ${activeModelId}`}</span>
+									<span class="badge badge-xs shrink-0">{effortLabel(displayModel?.effort)}</span>
 								</div>
 								<input
 									type="range"
diff --git a/packages/frontend/src/lib/components/SidebarPanel.svelte b/packages/frontend/src/lib/components/SidebarPanel.svelte
index 491b1bd..3372396 100644
--- a/packages/frontend/src/lib/components/SidebarPanel.svelte
+++ b/packages/frontend/src/lib/components/SidebarPanel.svelte
@@ -34,7 +34,7 @@ const {
 	reasoningEffort = "max",
 	activeAgentSlug = null as string | null,
 	activeTabParentId = null as string | null,
-	activeAgentModels = null as Array<{ key_id: string; model_id: string }> | null,
+	activeAgentModels = null as Array<{ key_id: string; model_id: string; effort?: string }> | null,
 	workingDirectory = null as string | null,
 	onKeyChange,
 	onModelChange,
@@ -54,7 +54,7 @@ const {
 	reasoningEffort?: string;
 	activeAgentSlug?: string | null;
 	activeTabParentId?: string | null;
-	activeAgentModels?: Array<{ key_id: string; model_id: string }> | null;
+	activeAgentModels?: Array<{ key_id: string; model_id: string; effort?: string }> | null;
 	workingDirectory?: string | null;
 	onKeyChange: (keyId: string) => void;
 	onModelChange: (keyId: string, modelId: string) => void;
diff --git a/packages/frontend/src/lib/tabs.svelte.ts b/packages/frontend/src/lib/tabs.svelte.ts
index 3fd7e5f..d3061c3 100644
--- a/packages/frontend/src/lib/tabs.svelte.ts
+++ b/packages/frontend/src/lib/tabs.svelte.ts
@@ -12,6 +12,12 @@ import {
 // source of truth for HISTORY; `groupRowsToMessages` derives render bubbles.
 import { groupRowsToMessages, type MessageRow } from "@dispatch/core/src/chunks/transform.js";
 import type { ChunkRow } from "@dispatch/core/src/types/index.js";
+import {
+	type AgentModelEntry,
+	DEFAULT_REASONING_EFFORT,
+	isReasoningEffort,
+	type ReasoningEffort,
+} from "@dispatch/core/src/types/index.js";
 import { config } from "./config.js";
 import { appSettings } from "./settings.svelte.js";
 import type {
@@ -154,7 +160,7 @@ export interface Tab {
 	agentStatus: "idle" | "running" | "error";
 	keyId: string | null;
 	modelId: string | null;
-	reasoningEffort: string;
+	reasoningEffort: ReasoningEffort;
 	currentAssistantId: string | null;
 	tasks: TaskItem[];
 	injectedSkills: string[];
@@ -162,7 +168,7 @@ export interface Tab {
 	persistent: boolean;
 	agentSlug: string | null;
 	agentScope: string | null;
-	agentModels: Array<{ key_id: string; model_id: string }> | null;
+	agentModels: AgentModelEntry[] | null;
 	workingDirectory: string | null;
 	queuedMessages: QueuedMessage[];
 	chunkLimit: number;
@@ -280,7 +286,7 @@ export function createTabStore() {
 			agentStatus: "idle",
 			keyId: null,
 			modelId: null,
-			reasoningEffort: "max",
+			reasoningEffort: DEFAULT_REASONING_EFFORT,
 			currentAssistantId: null,
 			tasks: [],
 			injectedSkills: [],
@@ -355,7 +361,7 @@ export function createTabStore() {
 				agentStatus: "idle",
 				keyId: tabData.keyId ?? null,
 				modelId: tabData.modelId ?? null,
-				reasoningEffort: "max",
+				reasoningEffort: DEFAULT_REASONING_EFFORT,
 				currentAssistantId: null,
 				tasks: [],
 				injectedSkills: [],
@@ -829,7 +835,7 @@ export function createTabStore() {
 				agentStatus,
 				keyId: row.keyId ?? null,
 				modelId: row.modelId ?? null,
-				reasoningEffort: "max",
+				reasoningEffort: DEFAULT_REASONING_EFFORT,
 				currentAssistantId,
 				tasks: [],
 				injectedSkills: [],
@@ -1154,7 +1160,7 @@ export function createTabStore() {
 					parentTabId: string | null;
 					agentSlug?: string | null;
 					workingDirectory: string | null;
-					agentModels?: Array<{ key_id: string; model_id: string }> | null;
+					agentModels?: AgentModelEntry[] | null;
 				};
 				// Only add if we don't already have this tab
 				if (!getTabById(newTabEvent.id)) {
@@ -1168,7 +1174,7 @@ export function createTabStore() {
 						agentStatus: "running",
 						keyId: newTabEvent.keyId ?? null,
 						modelId: newTabEvent.modelId ?? null,
-						reasoningEffort: "max",
+						reasoningEffort: DEFAULT_REASONING_EFFORT,
 						currentAssistantId: null,
 						tasks: [],
 						injectedSkills: [],
@@ -1382,7 +1388,7 @@ export function createTabStore() {
 					name: string;
 					skills: string[];
 					tools: string[];
-					models: Array<{ key_id: string; model_id: string }>;
+					models: AgentModelEntry[];
 					cwd?: string;
 				}>;
 			};
@@ -1451,7 +1457,7 @@ export function createTabStore() {
 				agents?: Array<{
 					slug: string;
 					scope: string;
-					models: Array<{ key_id: string; model_id: string }>;
+					models: AgentModelEntry[];
 					cwd?: string;
 				}>;
 			};
@@ -1733,6 +1739,19 @@ export function createTabStore() {
 		}).catch(() => {});
 	}
 
+	/**
+	 * Update the per-tab reasoning-effort selector. Ignores unrecognised
+	 * values so an out-of-range string from the UI can't corrupt the tab
+	 * state. This is the per-tab effort in the per-model → per-tab → default
+	 * resolution chain.
+	 */
+	function setReasoningEffort(effort: string): void {
+		if (!isReasoningEffort(effort)) return;
+		const tab = getActiveTab();
+		if (!tab) return;
+		updateTab(tab.id, { reasoningEffort: effort });
+	}
+
 	function setWorkingDirectory(dir: string | null): void {
 		const tab = getActiveTab();
 		if (!tab) return;
@@ -1745,7 +1764,7 @@ export function createTabStore() {
 			scope: string;
 			skills: string[];
 			tools: string[];
-			models: Array<{ key_id: string; model_id: string }>;
+			models: AgentModelEntry[];
 			cwd?: string;
 		} | null,
 	): void {
@@ -2002,6 +2021,7 @@ export function createTabStore() {
 		stopGeneration,
 		changeModel,
 		setKey,
+		setReasoningEffort,
 		setAgent,
 		replyPermission,
 		copyConversation,