story-kit: merge 339_story_web_ui_agent_assignment_dropdown_on_work_items

frontend/src/api/agents.test.ts

@@ -36,6 +36,7 @@ const sampleAgent: AgentInfo = {
 const sampleConfig: AgentConfigInfo = {
 	name: "coder",
 	role: "engineer",
+	stage: "coder",
 	model: "claude-sonnet-4-6",
 	allowed_tools: null,
 	max_turns: null,

frontend/src/api/agents.ts

@@ -31,6 +31,7 @@ export interface AgentEvent {
 export interface AgentConfigInfo {
 	name: string;
 	role: string;
+	stage: string | null;
 	model: string | null;
 	allowed_tools: string[] | null;
 	max_turns: number | null;

frontend/src/components/AgentPanel.test.tsx

@@ -29,6 +29,7 @@ const ROSTER: AgentConfigInfo[] = [
 	{
 		name: "coder-1",
 		role: "Full-stack engineer",
+		stage: "coder",
 		model: "sonnet",
 		allowed_tools: null,
 		max_turns: 50,

frontend/src/components/WorkItemDetailPanel.test.tsx

@@ -20,6 +20,9 @@ vi.mock("../api/client", async () => {
 vi.mock("../api/agents", () => ({
 	agentsApi: {
 		listAgents: vi.fn(),
+		getAgentConfig: vi.fn(),
+		stopAgent: vi.fn(),
+		startAgent: vi.fn(),
 	},
 	subscribeAgentStream: vi.fn(() => () => {}),
 }));
@@ -33,6 +36,7 @@ const mockedGetWorkItemContent = vi.mocked(api.getWorkItemContent);
 const mockedGetTestResults = vi.mocked(api.getTestResults);
 const mockedGetTokenCost = vi.mocked(api.getTokenCost);
 const mockedListAgents = vi.mocked(agentsApi.listAgents);
+const mockedGetAgentConfig = vi.mocked(agentsApi.getAgentConfig);
 const mockedSubscribeAgentStream = vi.mocked(subscribeAgentStream);
 
 const DEFAULT_CONTENT = {
@@ -56,6 +60,7 @@ beforeEach(() => {
 	mockedGetTestResults.mockResolvedValue(null);
 	mockedGetTokenCost.mockResolvedValue({ total_cost_usd: 0, agents: [] });
 	mockedListAgents.mockResolvedValue([]);
+	mockedGetAgentConfig.mockResolvedValue([]);
 	mockedSubscribeAgentStream.mockReturnValue(() => {});
 });
 

frontend/src/components/WorkItemDetailPanel.tsx

@@ -1,6 +1,11 @@
 import * as React from "react";
 import Markdown from "react-markdown";
-import type { AgentEvent, AgentInfo, AgentStatusValue } from "../api/agents";
+import type {
+	AgentConfigInfo,
+	AgentEvent,
+	AgentInfo,
+	AgentStatusValue,
+} from "../api/agents";
 import { agentsApi, subscribeAgentStream } from "../api/agents";
 import type {
 	AgentCostEntry,
@@ -10,7 +15,7 @@ import type {
 } from "../api/client";
 import { api } from "../api/client";
 
-const { useEffect, useRef, useState } = React;
+const { useCallback, useEffect, useRef, useState } = React;
 
 const STAGE_LABELS: Record<string, string> = {
 	backlog: "Backlog",
@@ -131,6 +136,9 @@ export function WorkItemDetailPanel({
 		null,
 	);
 	const [tokenCost, setTokenCost] = useState<TokenCostResponse | null>(null);
+	const [agentConfig, setAgentConfig] = useState<AgentConfigInfo[]>([]);
+	const [assigning, setAssigning] = useState(false);
+	const [assignError, setAssignError] = useState<string | null>(null);
 	const panelRef = useRef<HTMLDivElement>(null);
 	const cleanupRef = useRef<(() => void) | null>(null);
 
@@ -242,6 +250,59 @@ export function WorkItemDetailPanel({
 		return () => window.removeEventListener("keydown", handleKeyDown);
 	}, [onClose]);
 
+	// Load agent config roster for the dropdown.
+	useEffect(() => {
+		agentsApi
+			.getAgentConfig()
+			.then((config) => {
+				setAgentConfig(config);
+			})
+			.catch((err: unknown) => {
+				console.error("Failed to load agent config:", err);
+			});
+	}, []);
+
+	// Map pipeline stage → agent stage filter.
+	const STAGE_TO_AGENT_STAGE: Record<string, string> = {
+		current: "coder",
+		qa: "qa",
+		merge: "mergemaster",
+	};
+
+	const filteredAgents = agentConfig.filter(
+		(a) => a.stage === STAGE_TO_AGENT_STAGE[stage],
+	);
+
+	// The currently active agent name for this story (running or pending).
+	const activeAgentName =
+		agentInfo && (agentStatus === "running" || agentStatus === "pending")
+			? agentInfo.agent_name
+			: null;
+
+	const handleAgentAssign = useCallback(
+		async (selectedAgentName: string) => {
+			setAssigning(true);
+			setAssignError(null);
+			try {
+				// Stop current running agent if there is one.
+				if (activeAgentName) {
+					await agentsApi.stopAgent(storyId, activeAgentName);
+				}
+				// Start the new agent (or skip if "none" selected).
+				if (selectedAgentName) {
+					await agentsApi.startAgent(storyId, selectedAgentName);
+				}
+			} catch (err: unknown) {
+				setAssignError(
+					err instanceof Error ? err.message : "Failed to assign agent",
+				);
+			} finally {
+				setAssigning(false);
+			}
+		},
+		[storyId, activeAgentName],
+	);
+
 	const stageLabel = STAGE_LABELS[stage] ?? stage;
 	const hasTestResults =
 		testResults &&
@@ -301,7 +362,72 @@ export function WorkItemDetailPanel({
 							{stageLabel}
 						</div>
 					)}
-					{assignedAgent ? (
+					{filteredAgents.length > 0 && (
+						<div
+							data-testid="detail-panel-agent-assignment"
+							style={{
+								display: "flex",
+								alignItems: "center",
+								gap: "6px",
+								marginTop: "4px",
+							}}
+						>
+							<span style={{ fontSize: "0.75em", color: "#666" }}>Agent:</span>
+							<select
+								data-testid="agent-assignment-dropdown"
+								disabled={assigning}
+								value={activeAgentName ?? assignedAgent ?? ""}
+								onChange={(e) => handleAgentAssign(e.target.value)}
+								style={{
+									background: "#1a1a1a",
+									border: "1px solid #444",
+									borderRadius: "4px",
+									color: "#ccc",
+									cursor: assigning ? "not-allowed" : "pointer",
+									fontSize: "0.75em",
+									padding: "2px 6px",
+									opacity: assigning ? 0.6 : 1,
+								}}
+							>
+								<option value="">— none —</option>
+								{filteredAgents.map((a) => {
+									const isRunning =
+										agentInfo?.agent_name === a.name &&
+										agentStatus === "running";
+									const isPending =
+										agentInfo?.agent_name === a.name &&
+										agentStatus === "pending";
+									const statusLabel = isRunning
+										? " — running"
+										: isPending
+											? " — pending"
+											: " — idle";
+									const modelPart = a.model ? ` (${a.model})` : "";
+									return (
+										<option key={a.name} value={a.name}>
+											{a.name}
+											{modelPart}
+											{statusLabel}
+										</option>
+									);
+								})}
+							</select>
+							{assigning && (
+								<span style={{ fontSize: "0.7em", color: "#888" }}>
+									Assigning…
+								</span>
+							)}
+							{assignError && (
+								<span
+									data-testid="agent-assignment-error"
+									style={{ fontSize: "0.7em", color: "#f85149" }}
+								>
+									{assignError}
+								</span>
+							)}
+						</div>
+					)}
+					{filteredAgents.length === 0 && assignedAgent ? (
 						<div
 							data-testid="detail-panel-assigned-agent"
 							style={{ fontSize: "0.75em", color: "#888" }}

server/src/http/agents.rs

@@ -37,6 +37,7 @@ struct AgentInfoResponse {
 struct AgentConfigInfoResponse {
     name: String,
     role: String,
+    stage: Option<String>,
     model: Option<String>,
     allowed_tools: Option<Vec<String>>,
     max_turns: Option<u32>,
@@ -275,6 +276,7 @@ impl AgentsApi {
                 .map(|a| AgentConfigInfoResponse {
                     name: a.name.clone(),
                     role: a.role.clone(),
+                    stage: a.stage.clone(),
                     model: a.model.clone(),
                     allowed_tools: a.allowed_tools.clone(),
                     max_turns: a.max_turns,
@@ -304,6 +306,7 @@ impl AgentsApi {
                 .map(|a| AgentConfigInfoResponse {
                     name: a.name.clone(),
                     role: a.role.clone(),
+                    stage: a.stage.clone(),
                     model: a.model.clone(),
                     allowed_tools: a.allowed_tools.clone(),
                     max_turns: a.max_turns,