Add per-task runtime selection to task create/edit

src/commands/task.ts

@@ -140,6 +140,7 @@ function formatTaskRecord(state: RuntimeWorkspaceStateResponse, task: RuntimeBoa
 		id: task.id,
 		prompt: task.prompt,
 		column: columnId,
+		agentId: task.agentId ?? null,
 		baseRef: task.baseRef,
 		startInPlanMode: task.startInPlanMode,
 		autoReviewEnabled: task.autoReviewEnabled === true,
@@ -427,6 +428,7 @@ async function startTask(input: { cwd: string; taskId: string; projectPath?: str
 			taskId: task.id,
 			prompt: task.prompt,
 			startInPlanMode: task.startInPlanMode,
+			agentId: task.agentId,
 			baseRef: task.baseRef,
 		});
 		if (!started.ok || !started.summary) {

src/core/api-contract.ts

@@ -73,6 +73,7 @@ export const runtimeBoardCardSchema = z.object({
 	startInPlanMode: z.boolean(),
 	autoReviewEnabled: z.boolean().optional(),
 	autoReviewMode: runtimeTaskAutoReviewModeSchema.optional(),
+	agentId: runtimeAgentIdSchema.optional(),
 	baseRef: z.string(),
 	createdAt: z.number(),
 	updatedAt: z.number(),
@@ -492,6 +493,7 @@ export const runtimeTaskSessionStartRequestSchema = z.object({
 	prompt: z.string(),
 	startInPlanMode: z.boolean().optional(),
 	resumeFromTrash: z.boolean().optional(),
+	agentId: runtimeAgentIdSchema.optional(),
 	baseRef: z.string(),
 	cols: z.number().int().positive().optional(),
 	rows: z.number().int().positive().optional(),

src/core/task-board-mutations.ts

@@ -1,4 +1,5 @@
 import type {
+	RuntimeAgentId,
 	RuntimeBoardCard,
 	RuntimeBoardColumnId,
 	RuntimeBoardData,
@@ -12,6 +13,7 @@ export interface RuntimeCreateTaskInput {
 	startInPlanMode?: boolean;
 	autoReviewEnabled?: boolean;
 	autoReviewMode?: RuntimeTaskAutoReviewMode;
+	agentId?: RuntimeAgentId;
 	baseRef: string;
 }
 
@@ -20,6 +22,7 @@ export interface RuntimeUpdateTaskInput {
 	startInPlanMode?: boolean;
 	autoReviewEnabled?: boolean;
 	autoReviewMode?: RuntimeTaskAutoReviewMode;
+	agentId?: RuntimeAgentId;
 	baseRef: string;
 }
 
@@ -266,6 +269,7 @@ export function addTaskToColumn(
 		startInPlanMode: Boolean(input.startInPlanMode),
 		autoReviewEnabled: Boolean(input.autoReviewEnabled),
 		autoReviewMode: normalizeTaskAutoReviewMode(input.autoReviewMode),
+		...(input.agentId ? { agentId: input.agentId } : {}),
 		baseRef,
 		createdAt: now,
 		updatedAt: now,
@@ -530,6 +534,7 @@ export function updateTask(
 				startInPlanMode: Boolean(input.startInPlanMode),
 				autoReviewEnabled: Boolean(input.autoReviewEnabled),
 				autoReviewMode: normalizeTaskAutoReviewMode(input.autoReviewMode),
+				agentId: input.agentId ?? card.agentId,
 				baseRef,
 				updatedAt: now,
 			};

src/terminal/agent-registry.ts

@@ -64,8 +64,12 @@ function getCuratedDefinitions(runtimeConfig: RuntimeConfigState, detected: stri
 	});
 }
 
-export function resolveAgentCommand(runtimeConfig: RuntimeConfigState): ResolvedAgentCommand | null {
-	const selected = RUNTIME_AGENT_CATALOG.find((entry) => entry.id === runtimeConfig.selectedAgentId);
+export function resolveAgentCommand(
+	runtimeConfig: RuntimeConfigState,
+	agentIdOverride?: RuntimeAgentId | null,
+): ResolvedAgentCommand | null {
+	const selectedAgentId = agentIdOverride ?? runtimeConfig.selectedAgentId;
+	const selected = RUNTIME_AGENT_CATALOG.find((entry) => entry.id === selectedAgentId);
 	if (!selected) {
 		return null;
 	}

src/trpc/runtime-api.ts

@@ -65,7 +65,7 @@ export function createRuntimeApi(deps: CreateRuntimeApiDependencies): RuntimeTrp
 			try {
 				const body = parseTaskSessionStartRequest(input);
 				const scopedRuntimeConfig = await deps.loadScopedRuntimeConfig(workspaceScope);
-				const resolved = resolveAgentCommand(scopedRuntimeConfig);
+				const resolved = resolveAgentCommand(scopedRuntimeConfig, body.agentId);
 				if (!resolved) {
 					return {
 						ok: false,

test/integration/workspace-state.integration.test.ts

@@ -18,7 +18,7 @@ import {
 import { createGitTestEnv } from "../utilities/git-env.js";
 import { createTempDir } from "../utilities/temp-dir.js";
 
-function createBoard(title: string): RuntimeBoardData {
+function createBoard(title: string, cardOverrides: Partial<RuntimeBoardData["columns"][number]["cards"][number]> = {}): RuntimeBoardData {
 	return {
 		columns: [
 			{
@@ -32,6 +32,7 @@ function createBoard(title: string): RuntimeBoardData {
 						baseRef: "main",
 						createdAt: Date.now(),
 						updatedAt: Date.now(),
+						...cardOverrides,
 					},
 				],
 			},
@@ -176,6 +177,27 @@ describe.sequential("workspace-state integration", () => {
 		});
 	});
 
+	it("round-trips per-task agent assignments through persisted workspace state", async () => {
+		await withTemporaryHome(async () => {
+			const { path: sandboxRoot, cleanup } = createTempDir("kanban-agent-persistence-");
+			try {
+				const workspacePath = join(sandboxRoot, "project-agent");
+				mkdirSync(workspacePath, { recursive: true });
+				initGitRepository(workspacePath);
+
+				await saveWorkspaceState(workspacePath, {
+					board: createBoard("Assigned task", { agentId: "codex" }),
+					sessions: {},
+				});
+
+				const loaded = await loadWorkspaceState(workspacePath);
+				expect(loaded.board.columns[0]?.cards[0]?.agentId).toBe("codex");
+			} finally {
+				cleanup();
+			}
+		});
+	});
+
 	it("creates readable workspace ids from folder names with random suffix on collisions", async () => {
 		await withTemporaryHome(async () => {
 			const { path: sandboxRoot, cleanup } = createTempDir("kanban-workspace-id-format-");

test/runtime/terminal/agent-registry.test.ts

@@ -54,6 +54,15 @@ describe("agent-registry", () => {
 
 		expect(resolved).toBeNull();
 	});
+
+	it("prefers an explicit task agent override when it is runnable", () => {
+		commandDiscoveryMocks.isBinaryAvailableOnPath.mockImplementation((binary: string) => binary === "codex");
+
+		const resolved = resolveAgentCommand(createRuntimeConfigState({ selectedAgentId: "claude" }), "codex");
+
+		expect(resolved?.agentId).toBe("codex");
+		expect(resolved?.binary).toBe("codex");
+	});
 });
 
 describe("buildRuntimeConfigResponse", () => {

test/runtime/trpc/runtime-api.test.ts

@@ -176,4 +176,50 @@ describe("createRuntimeApi startTaskSession", () => {
 			ensure: true,
 		});
 	});
+
+	it("uses the task agent override when starting a session", async () => {
+		taskWorktreeMocks.resolveTaskCwd.mockResolvedValue("/tmp/existing-worktree");
+		agentRegistryMocks.resolveAgentCommand.mockReturnValue({
+			agentId: "codex",
+			label: "OpenAI Codex",
+			command: "codex",
+			binary: "codex",
+			args: [],
+		});
+
+		const terminalManager = {
+			startTaskSession: vi.fn(async () => createSummary({ agentId: "codex" })),
+			applyTurnCheckpoint: vi.fn(),
+		};
+		const runtimeConfig = createRuntimeConfigState();
+		const api = createRuntimeApi({
+			getActiveWorkspaceId: vi.fn(() => "workspace-1"),
+			loadScopedRuntimeConfig: vi.fn(async () => runtimeConfig),
+			setActiveRuntimeConfig: vi.fn(),
+			getScopedTerminalManager: vi.fn(async () => terminalManager as never),
+			resolveInteractiveShellCommand: vi.fn(),
+			runCommand: vi.fn(),
+		});
+
+		const response = await api.startTaskSession(
+			{
+				workspaceId: "workspace-1",
+				workspacePath: "/tmp/repo",
+			},
+			{
+				taskId: "task-1",
+				baseRef: "main",
+				prompt: "Use codex for this task",
+				agentId: "codex",
+			},
+		);
+
+		expect(response.ok).toBe(true);
+		expect(agentRegistryMocks.resolveAgentCommand).toHaveBeenCalledWith(runtimeConfig, "codex");
+		expect(terminalManager.startTaskSession).toHaveBeenCalledWith(
+			expect.objectContaining({
+				agentId: "codex",
+			}),
+		);
+	});
 });

web-ui/src/App.tsx

@@ -111,6 +111,15 @@ export default function App(): ReactElement {
 	} = useTerminalConnectionReady();
 	const readyForReviewNotificationsEnabled = runtimeProjectConfig?.readyForReviewNotificationsEnabled ?? true;
 	const shortcuts = runtimeProjectConfig?.shortcuts ?? [];
+	const taskAgentOptions = useMemo(
+		() =>
+			(runtimeProjectConfig?.agents ?? []).map((agent) => ({
+				value: agent.id,
+				label: agent.label,
+				installed: agent.installed,
+			})),
+		[runtimeProjectConfig?.agents],
+	);
 	const selectedShortcutLabel = useMemo(() => {
 		if (shortcuts.length === 0) {
 			return null;
@@ -219,6 +228,8 @@ export default function App(): ReactElement {
 		setNewTaskAutoReviewEnabled,
 		newTaskAutoReviewMode,
 		setNewTaskAutoReviewMode,
+		newTaskAgentId,
+		setNewTaskAgentId,
 		isNewTaskStartInPlanModeDisabled,
 		newTaskBranchRef,
 		setNewTaskBranchRef,
@@ -231,6 +242,8 @@ export default function App(): ReactElement {
 		setEditTaskAutoReviewEnabled,
 		editTaskAutoReviewMode,
 		setEditTaskAutoReviewMode,
+		editTaskAgentId,
+		setEditTaskAgentId,
 		isEditTaskStartInPlanModeDisabled,
 		editTaskBranchRef,
 		setEditTaskBranchRef,
@@ -635,6 +648,9 @@ export default function App(): ReactElement {
 			onAutoReviewEnabledChange={setEditTaskAutoReviewEnabled}
 			autoReviewMode={editTaskAutoReviewMode}
 			onAutoReviewModeChange={setEditTaskAutoReviewMode}
+			agentId={editTaskAgentId}
+			agentOptions={taskAgentOptions}
+			onAgentIdChange={setEditTaskAgentId}
 			workspaceId={currentProjectId}
 			branchRef={editTaskBranchRef}
 			branchOptions={createTaskBranchOptions}
@@ -920,6 +936,9 @@ export default function App(): ReactElement {
 				onAutoReviewEnabledChange={setNewTaskAutoReviewEnabled}
 				autoReviewMode={newTaskAutoReviewMode}
 				onAutoReviewModeChange={setNewTaskAutoReviewMode}
+				agentId={newTaskAgentId}
+				agentOptions={taskAgentOptions}
+				onAgentIdChange={setNewTaskAgentId}
 				workspaceId={currentProjectId}
 				branchRef={newTaskBranchRef}
 				branchOptions={createTaskBranchOptions}

web-ui/src/components/task-agent-select.tsx

@@ -0,0 +1,51 @@
+import { ChevronDown } from "lucide-react";
+import type { ReactElement } from "react";
+
+import type { RuntimeAgentId } from "@/runtime/types";
+
+export interface TaskAgentOption {
+	value: RuntimeAgentId;
+	label: string;
+	installed: boolean;
+}
+
+export function TaskAgentSelect({
+	id,
+	value,
+	options,
+	onChange,
+}: {
+	id?: string;
+	value: RuntimeAgentId | null;
+	options: TaskAgentOption[];
+	onChange: (value: RuntimeAgentId) => void;
+}): ReactElement {
+	return (
+		<div>
+			<span className="text-[11px] text-text-secondary block mb-1">Agent runtime</span>
+			<div className="relative inline-flex w-full">
+				<select
+					id={id}
+					value={value ?? ""}
+					onChange={(event) => onChange(event.currentTarget.value as RuntimeAgentId)}
+					className="h-8 w-full appearance-none rounded-md border border-border-bright bg-surface-2 pl-2 pr-7 text-[12px] text-text-primary cursor-pointer focus:border-border-focus focus:outline-none disabled:cursor-default disabled:text-text-secondary"
+					disabled={options.length === 0}
+				>
+					<option value="" disabled>
+						{options.length === 0 ? "Loading runtimes…" : "Select runtime"}
+					</option>
+					{options.map((option) => (
+						<option key={option.value} value={option.value} disabled={!option.installed}>
+							{option.label}
+							{option.installed ? "" : " (not installed)"}
+						</option>
+					))}
+				</select>
+				<ChevronDown
+					size={14}
+					className="pointer-events-none absolute right-1.5 top-1/2 -translate-y-1/2 text-text-secondary"
+				/>
+			</div>
+		</div>
+	);
+}

web-ui/src/components/task-create-dialog.tsx

@@ -15,11 +15,13 @@ import type { ReactElement } from "react";
 import { useCallback, useEffect, useId, useMemo, useRef, useState } from "react";
 import { useHotkeys } from "react-hotkeys-hook";
 
+import { TaskAgentSelect, type TaskAgentOption } from "@/components/task-agent-select";
 import type { BranchSelectOption } from "@/components/branch-select-dropdown";
 import { BranchSelectDropdown } from "@/components/branch-select-dropdown";
 import { TaskPromptComposer } from "@/components/task-prompt-composer";
 import { Button } from "@/components/ui/button";
 import { Dialog, DialogBody, DialogFooter, DialogHeader } from "@/components/ui/dialog";
+import type { RuntimeAgentId } from "@/runtime/types";
 import type { TaskAutoReviewMode } from "@/types";
 
 const AUTO_REVIEW_MODE_OPTIONS: Array<{ value: TaskAutoReviewMode; label: string }> = [
@@ -76,6 +78,9 @@ export function TaskCreateDialog({
 	onAutoReviewEnabledChange,
 	autoReviewMode,
 	onAutoReviewModeChange,
+	agentId,
+	agentOptions,
+	onAgentIdChange,
 	startInPlanModeDisabled = false,
 	workspaceId,
 	branchRef,
@@ -96,6 +101,9 @@ export function TaskCreateDialog({
 	onAutoReviewEnabledChange: (value: boolean) => void;
 	autoReviewMode: TaskAutoReviewMode;
 	onAutoReviewModeChange: (value: TaskAutoReviewMode) => void;
+	agentId: RuntimeAgentId | null;
+	agentOptions: TaskAgentOption[];
+	onAgentIdChange: (value: RuntimeAgentId) => void;
 	startInPlanModeDisabled?: boolean;
 	workspaceId: string | null;
 	branchRef: string;
@@ -108,6 +116,7 @@ export function TaskCreateDialog({
 	const nextFocusIndexRef = useRef<number | null>(null);
 	const startInPlanModeId = useId();
 	const autoReviewEnabledId = useId();
+	const agentSelectId = useId();
 
 	const detectedItems = useMemo(() => parseListItems(prompt), [prompt]);
 	const validTaskCount = useMemo(
@@ -380,6 +389,13 @@ export function TaskCreateDialog({
 						/>
 					</div>
 
+					<TaskAgentSelect
+						id={agentSelectId}
+						value={agentId}
+						options={agentOptions}
+						onChange={onAgentIdChange}
+					/>
+
 					<div className="flex items-center gap-2 flex-wrap">
 						<label
 							htmlFor={autoReviewEnabledId}