chore: switch mergemaster to opus and add cargo fmt guidance

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/api/gateway.ts

@@ -8,6 +8,18 @@ export interface JoinedAgent {
 	label: string;
 	address: string;
 	registered_at: number;
+	/// Project this agent is assigned to, if any.
+	assigned_project?: string;
+}
+
+export interface GatewayProject {
+	name: string;
+	url: string;
+}
+
+export interface GatewayInfo {
+	active: string;
+	projects: GatewayProject[];
 }
 
 export interface GenerateTokenResponse {
@@ -61,4 +73,17 @@ export const gatewayApi = {
 			method: "DELETE",
 		});
 	},
+
+	/// Assign an agent to a project, or unassign it by passing null.
+	assignAgent(id: string, project: string | null): Promise<JoinedAgent> {
+		return gatewayRequest<JoinedAgent>(`/gateway/agents/${id}/assign`, {
+			method: "POST",
+			body: JSON.stringify({ project }),
+		});
+	},
+
+	/// Get the list of registered projects from the gateway.
+	getGatewayInfo(): Promise<GatewayInfo> {
+		return gatewayRequest<GatewayInfo>("/api/gateway");
+	},
 };

frontend/src/components/GatewayPanel.tsx

@@ -3,10 +3,10 @@
 /// Provides:
 /// - An "Add Agent" button that generates a one-time join token.
 /// - Instructions for running a build agent with the token.
-/// - A list of connected agents with per-agent "Remove" buttons.
+/// - A list of connected agents with per-agent project assignment and "Remove" buttons.
 
 import * as React from "react";
-import { gatewayApi, type JoinedAgent } from "../api/gateway";
+import { gatewayApi, type JoinedAgent, type GatewayProject } from "../api/gateway";
 
 const { useCallback, useEffect, useState } = React;
 
@@ -90,12 +90,17 @@ function TokenDisplay({ token }: { token: string }) {
 
 function AgentRow({
 	agent,
+	projects,
 	onRemove,
+	onAssign,
 }: {
 	agent: JoinedAgent;
+	projects: GatewayProject[];
 	onRemove: (id: string) => void;
+	onAssign: (id: string, project: string | null) => void;
 }) {
 	const registeredAt = new Date(agent.registered_at * 1000).toLocaleString();
+	const isAssigned = Boolean(agent.assigned_project);
 
 	return (
 		<div
@@ -116,9 +121,10 @@ function AgentRow({
 					width: "8px",
 					height: "8px",
 					borderRadius: "50%",
-					background: "#3fb950",
+					background: isAssigned ? "#3fb950" : "#6e7681",
 					flexShrink: 0,
 				}}
+				title={isAssigned ? "Assigned" : "Idle (unassigned)"}
 			/>
 			<div style={{ flex: 1 }}>
 				<div style={{ fontWeight: 600, color: "#e6edf3" }}>{agent.label}</div>
@@ -129,6 +135,29 @@ function AgentRow({
 					Registered {registeredAt}
 				</div>
 			</div>
+			<select
+				data-testid={`assign-agent-${agent.id}`}
+				value={agent.assigned_project ?? ""}
+				onChange={(e) =>
+					onAssign(agent.id, e.target.value === "" ? null : e.target.value)
+				}
+				style={{
+					fontSize: "0.8em",
+					padding: "4px 8px",
+					borderRadius: "4px",
+					border: "1px solid #30363d",
+					background: "#0d1117",
+					color: "#e6edf3",
+					cursor: "pointer",
+				}}
+			>
+				<option value="">— unassigned —</option>
+				{projects.map((p) => (
+					<option key={p.name} value={p.name}>
+						{p.name}
+					</option>
+				))}
+			</select>
 			<button
 				type="button"
 				data-testid={`remove-agent-${agent.id}`}
@@ -152,6 +181,7 @@ function AgentRow({
 /// Gateway management panel — rendered when running in `--gateway` mode.
 export function GatewayPanel() {
 	const [agents, setAgents] = useState<JoinedAgent[]>([]);
+	const [projects, setProjects] = useState<GatewayProject[]>([]);
 	const [token, setToken] = useState<string | null>(null);
 	const [generating, setGenerating] = useState(false);
 	const [error, setError] = useState<string | null>(null);
@@ -161,6 +191,10 @@ export function GatewayPanel() {
 			.listAgents()
 			.then(setAgents)
 			.catch(() => setAgents([]));
+		gatewayApi
+			.getGatewayInfo()
+			.then((info) => setProjects(info.projects))
+			.catch(() => setProjects([]));
 	}, []);
 
 	const handleAddAgent = useCallback(async () => {
@@ -186,6 +220,20 @@ export function GatewayPanel() {
 		}
 	}, []);
 
+	const handleAssignAgent = useCallback(
+		async (id: string, project: string | null) => {
+			try {
+				const updated = await gatewayApi.assignAgent(id, project);
+				setAgents((prev) =>
+					prev.map((a) => (a.id === updated.id ? updated : a)),
+				);
+			} catch (e) {
+				setError(e instanceof Error ? e.message : String(e));
+			}
+		},
+		[],
+	);
+
 	return (
 		<div
 			style={{
@@ -273,7 +321,9 @@ export function GatewayPanel() {
 								<AgentRow
 									key={agent.id}
 									agent={agent}
+									projects={projects}
 									onRemove={handleRemoveAgent}
+									onAssign={handleAssignAgent}
 								/>
 							))}
 						</div>