9 files changed, 432 insertions, 0 deletions
diff --git a/packages/api/package.json b/packages/api/package.json
new file mode 100644
index 0000000..deea9f6
--- /dev/null
+++ b/packages/api/package.json
@@ -0,0 +1,20 @@
+{
+	"name": "@dispatch/api",
+	"version": "0.0.1",
+	"private": true,
+	"type": "module",
+	"main": "src/index.ts",
+	"scripts": {
+		"dev": "bun --watch src/index.ts",
+		"test": "vitest run",
+		"test:watch": "vitest",
+		"typecheck": "tsc --noEmit"
+	},
+	"dependencies": {
+		"hono": "^4.0.0",
+		"@dispatch/core": "workspace:*"
+	},
+	"devDependencies": {
+		"@types/bun": "latest"
+	}
+}
diff --git a/packages/api/src/agent-manager.ts b/packages/api/src/agent-manager.ts
new file mode 100644
index 0000000..f60b8d3
--- /dev/null
+++ b/packages/api/src/agent-manager.ts
@@ -0,0 +1,86 @@
+import {
+	Agent,
+	type AgentEvent,
+	type AgentStatus,
+	createListFilesTool,
+	createReadFileTool,
+	createWriteFileTool,
+} from "@dispatch/core";
+
+const SYSTEM_PROMPT = `You are Dispatch, a helpful AI coding assistant. You have access to the following tools for working with files in the current working directory:
+
+- read_file: Read the contents of a file
+- write_file: Write content to a file (creates parent directories if needed)
+- list_files: List files and directories
+
+When asked to work with files, use these tools. Always confirm what you did after completing an action. Be concise and helpful.`;
+
+export class AgentManager {
+	private agent: Agent | null = null;
+	private status: AgentStatus = "idle";
+	private messageCount = 0;
+	private eventListeners: Set<(event: AgentEvent) => void> = new Set();
+
+	private getOrCreateAgent(): Agent {
+		if (!this.agent) {
+			const apiKey = process.env.OPENCODE_API_KEY ?? "";
+			const model = process.env.DISPATCH_MODEL ?? "deepseek-v4-flash-free";
+			const workingDirectory = process.env.DISPATCH_WORKING_DIR ?? process.cwd();
+
+			const tools = [
+				createReadFileTool(workingDirectory),
+				createWriteFileTool(workingDirectory),
+				createListFilesTool(workingDirectory),
+			];
+
+			this.agent = new Agent({
+				model,
+				apiKey,
+				baseURL: "https://opencode.ai/zen/v1",
+				systemPrompt: SYSTEM_PROMPT,
+				tools,
+				workingDirectory,
+			});
+		}
+		return this.agent;
+	}
+
+	getStatus(): AgentStatus {
+		return this.status;
+	}
+
+	getMessageCount(): number {
+		return this.messageCount;
+	}
+
+	onEvent(listener: (event: AgentEvent) => void): () => void {
+		this.eventListeners.add(listener);
+		return () => {
+			this.eventListeners.delete(listener);
+		};
+	}
+
+	private emit(event: AgentEvent): void {
+		for (const listener of this.eventListeners) {
+			listener(event);
+		}
+	}
+
+	async processMessage(message: string): Promise<void> {
+		const agent = this.getOrCreateAgent();
+
+		this.messageCount += 1;
+
+		try {
+			for await (const event of agent.run(message)) {
+				this.status = event.type === "status" ? event.status : this.status;
+				this.emit(event);
+			}
+		} catch (err) {
+			const errorMsg = err instanceof Error ? err.message : String(err);
+			this.status = "error";
+			this.emit({ type: "error", error: errorMsg });
+			this.emit({ type: "status", status: "error" });
+		}
+	}
+}
diff --git a/packages/api/src/app.ts b/packages/api/src/app.ts
new file mode 100644
index 0000000..9c31eab
--- /dev/null
+++ b/packages/api/src/app.ts
@@ -0,0 +1,46 @@
+import { Hono } from "hono";
+import { cors } from "hono/cors";
+import { AgentManager } from "./agent-manager.js";
+
+export const agentManager = new AgentManager();
+
+export const app = new Hono();
+
+app.use(
+	"*",
+	cors({
+		origin: "http://localhost:5173",
+		credentials: true,
+		allowHeaders: ["Content-Type", "Authorization"],
+		allowMethods: ["GET", "POST", "OPTIONS"],
+	}),
+);
+
+app.get("/health", (c) => {
+	return c.json({ ok: true });
+});
+
+app.get("/status", (c) => {
+	return c.json({
+		status: agentManager.getStatus(),
+		messageCount: agentManager.getMessageCount(),
+	});
+});
+
+app.post("/chat", async (c) => {
+	const body = await c.req.json<{ message?: unknown }>();
+	const message = body.message;
+
+	if (typeof message !== "string" || message.trim() === "") {
+		return c.json({ error: "message must be a non-empty string" }, 400);
+	}
+
+	if (agentManager.getStatus() === "running") {
+		return c.json({ error: "agent is already running" }, 409);
+	}
+
+	// Non-blocking — let the agent run in the background
+	agentManager.processMessage(message).catch(console.error);
+
+	return c.json({ status: "ok" });
+});
diff --git a/packages/api/src/index.ts b/packages/api/src/index.ts
new file mode 100644
index 0000000..02b04b6
--- /dev/null
+++ b/packages/api/src/index.ts
@@ -0,0 +1,37 @@
+import { createBunWebSocket } from "hono/bun";
+import { agentManager, app } from "./app.js";
+
+const { upgradeWebSocket, websocket } = createBunWebSocket();
+
+app.get(
+	"/ws",
+	upgradeWebSocket((_c) => {
+		return {
+			onOpen(_event, ws) {
+				// Send current status immediately
+				ws.send(JSON.stringify({ type: "status", status: agentManager.getStatus() }));
+
+				const unsubscribe = agentManager.onEvent((event) => {
+					ws.send(JSON.stringify(event));
+				});
+
+				// Store unsubscribe fn on the raw socket for cleanup
+				(ws as unknown as { _unsub?: () => void })._unsub = unsubscribe;
+			},
+			onClose(_event, ws) {
+				const unsub = (ws as unknown as { _unsub?: () => void })._unsub;
+				if (unsub) {
+					unsub();
+				}
+			},
+		};
+	}),
+);
+
+export { app };
+
+export default {
+	port: 3000,
+	fetch: app.fetch,
+	websocket,
+};
diff --git a/packages/api/src/types.ts b/packages/api/src/types.ts
new file mode 100644
index 0000000..a88e41b
--- /dev/null
+++ b/packages/api/src/types.ts
@@ -0,0 +1,2 @@
+// Re-export types from @dispatch/core for convenience
+export type { AgentEvent, AgentStatus } from "@dispatch/core";
diff --git a/packages/api/tests/agent-manager.test.ts b/packages/api/tests/agent-manager.test.ts
new file mode 100644
index 0000000..17b0bff
--- /dev/null
+++ b/packages/api/tests/agent-manager.test.ts
@@ -0,0 +1,113 @@
+import type { AgentEvent } from "@dispatch/core";
+import { describe, expect, it, vi } from "vitest";
+
+// Mock @dispatch/core's Agent to avoid real LLM calls
+vi.mock("@dispatch/core", async () => {
+	const actual = await vi.importActual<typeof import("@dispatch/core")>("@dispatch/core");
+	return {
+		...actual,
+		Agent: class MockAgent {
+			status = "idle";
+			messages: unknown[] = [];
+			async *run(_message: string) {
+				yield { type: "status", status: "running" } as const;
+				await new Promise<void>((r) => setTimeout(r, 10));
+				yield { type: "text-delta", delta: "Hello " } as const;
+				yield { type: "text-delta", delta: "world" } as const;
+				yield {
+					type: "done",
+					message: { role: "assistant", content: "Hello world" },
+				} as const;
+				yield { type: "status", status: "idle" } as const;
+			}
+		},
+	};
+});
+
+// Import after mock is defined (Vitest hoists vi.mock automatically)
+const { AgentManager } = await import("../src/agent-manager.js");
+
+describe("AgentManager", () => {
+	it("initial status is idle", () => {
+		const manager = new AgentManager();
+		expect(manager.getStatus()).toBe("idle");
+	});
+
+	it("initial messageCount is 0", () => {
+		const manager = new AgentManager();
+		expect(manager.getMessageCount()).toBe(0);
+	});
+
+	it("event listeners receive events during processMessage", async () => {
+		const manager = new AgentManager();
+		const events: AgentEvent[] = [];
+		manager.onEvent((event) => {
+			events.push(event);
+		});
+
+		await manager.processMessage("test");
+
+		expect(events.length).toBeGreaterThan(0);
+		expect(events[0]).toEqual({ type: "status", status: "running" });
+
+		const lastEvent = events[events.length - 1];
+		expect(lastEvent).toEqual({ type: "status", status: "idle" });
+
+		const doneEvent = events.find((e) => e.type === "done");
+		expect(doneEvent).toBeDefined();
+	});
+
+	it("emits text-delta events during processMessage", async () => {
+		const manager = new AgentManager();
+		const events: AgentEvent[] = [];
+		manager.onEvent((event) => {
+			events.push(event);
+		});
+
+		await manager.processMessage("hello");
+
+		const textDeltas = events.filter((e) => e.type === "text-delta");
+		expect(textDeltas.length).toBeGreaterThan(0);
+	});
+
+	it("messageCount increments after processMessage", async () => {
+		const manager = new AgentManager();
+		await manager.processMessage("hello");
+		expect(manager.getMessageCount()).toBe(1);
+		await manager.processMessage("world");
+		expect(manager.getMessageCount()).toBe(2);
+	});
+
+	it("status returns to idle after processMessage completes", async () => {
+		const manager = new AgentManager();
+		await manager.processMessage("test");
+		expect(manager.getStatus()).toBe("idle");
+	});
+
+	it("unsubscribe removes listener", async () => {
+		const manager = new AgentManager();
+		const events: AgentEvent[] = [];
+		const unsubscribe = manager.onEvent((event) => {
+			events.push(event);
+		});
+
+		unsubscribe();
+		await manager.processMessage("test");
+
+		expect(events.length).toBe(0);
+	});
+
+	it("multiple listeners all receive events", async () => {
+		const manager = new AgentManager();
+		const listener1 = vi.fn();
+		const listener2 = vi.fn();
+
+		manager.onEvent(listener1);
+		manager.onEvent(listener2);
+
+		await manager.processMessage("test");
+
+		expect(listener1).toHaveBeenCalled();
+		expect(listener2).toHaveBeenCalled();
+	});
+});
diff --git a/packages/api/tests/routes.test.ts b/packages/api/tests/routes.test.ts
new file mode 100644
index 0000000..d5384b3
--- /dev/null
+++ b/packages/api/tests/routes.test.ts
@@ -0,0 +1,106 @@
+import { describe, expect, it, vi } from "vitest";
+
+// Mock @dispatch/core's Agent to avoid real LLM calls
+vi.mock("@dispatch/core", async () => {
+	const actual = await vi.importActual<typeof import("@dispatch/core")>("@dispatch/core");
+	return {
+		...actual,
+		Agent: class MockAgent {
+			status = "idle";
+			messages: unknown[] = [];
+			async *run(_message: string) {
+				yield { type: "status", status: "running" } as const;
+				// Simulate some processing time so status stays "running"
+				await new Promise<void>((r) => setTimeout(r, 100));
+				yield { type: "text-delta", delta: "Hello " } as const;
+				yield { type: "text-delta", delta: "world" } as const;
+				yield {
+					type: "done",
+					message: { role: "assistant", content: "Hello world" },
+				} as const;
+				yield { type: "status", status: "idle" } as const;
+			}
+		},
+	};
+});
+
+const { app } = await import("../src/app.js");
+
+describe("GET /health", () => {
+	it("returns 200 with ok: true", async () => {
+		const res = await app.request("/health");
+		expect(res.status).toBe(200);
+		const body = await res.json();
+		expect(body).toEqual({ ok: true });
+	});
+});
+
+describe("GET /status", () => {
+	it("returns idle status initially", async () => {
+		const res = await app.request("/status");
+		expect(res.status).toBe(200);
+		const body = await res.json();
+		expect(body.status).toBe("idle");
+		expect(typeof body.messageCount).toBe("number");
+	});
+});
+
+describe("POST /chat", () => {
+	it("returns 200 with valid message", async () => {
+		const res = await app.request("/chat", {
+			method: "POST",
+			headers: { "Content-Type": "application/json" },
+			body: JSON.stringify({ message: "hello world" }),
+		});
+		expect(res.status).toBe(200);
+		const body = await res.json();
+		expect(body).toEqual({ status: "ok" });
+	});
+
+	it("returns 400 with empty message", async () => {
+		const res = await app.request("/chat", {
+			method: "POST",
+			headers: { "Content-Type": "application/json" },
+			body: JSON.stringify({ message: "" }),
+		});
+		expect(res.status).toBe(400);
+	});
+
+	it("returns 400 with whitespace-only message", async () => {
+		const res = await app.request("/chat", {
+			method: "POST",
+			headers: { "Content-Type": "application/json" },
+			body: JSON.stringify({ message: "   " }),
+		});
+		expect(res.status).toBe(400);
+	});
+
+	it("returns 400 with missing message field", async () => {
+		const res = await app.request("/chat", {
+			method: "POST",
+			headers: { "Content-Type": "application/json" },
+			body: JSON.stringify({}),
+		});
+		expect(res.status).toBe(400);
+	});
+
+	it("returns 409 when agent is already running", async () => {
+		// Start a message (non-blocking)
+		await app.request("/chat", {
+			method: "POST",
+			headers: { "Content-Type": "application/json" },
+			body: JSON.stringify({ message: "first message" }),
+		});
+
+		// Small delay to let the async generator start and emit "running" status
+		await new Promise<void>((r) => setTimeout(r, 20));
+
+		// Immediately send a second — agent should be running
+		const res = await app.request("/chat", {
+			method: "POST",
+			headers: { "Content-Type": "application/json" },
+			body: JSON.stringify({ message: "second message" }),
+		});
+		expect(res.status).toBe(409);
+	});
+});
diff --git a/packages/api/tsconfig.json b/packages/api/tsconfig.json
new file mode 100644
index 0000000..2d6fedd
--- /dev/null
+++ b/packages/api/tsconfig.json
@@ -0,0 +1,10 @@
+{
+	"extends": "../../tsconfig.base.json",
+	"compilerOptions": {
+		"outDir": "dist",
+		"rootDir": "src",
+		"types": ["@types/bun"]
+	},
+	"include": ["src/**/*.ts"],
+	"exclude": ["node_modules", "dist", "tests"]
+}
diff --git a/packages/api/vitest.config.ts b/packages/api/vitest.config.ts
new file mode 100644
index 0000000..854422e
--- /dev/null
+++ b/packages/api/vitest.config.ts
@@ -0,0 +1,12 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+	test: {
+		include: ["tests/**/*.test.ts"],
+		server: {
+			deps: {
+				inline: ["zod", "@dispatch/core"],
+			},
+		},
+	},
+});