diff --git a/packages/desktop/src/main/sidecar/controller.test.ts b/packages/desktop/src/main/sidecar/controller.test.ts
new file mode 100644
index 000000000000..24d831848b47
--- /dev/null
+++ b/packages/desktop/src/main/sidecar/controller.test.ts
@@ -0,0 +1,71 @@
+import { describe, expect, test, vi } from "bun:test"
+import { BaseSidecarController, createLocalSidecarController, createWslSidecarController } from "./types"
+
+describe("SidecarController Interface", () => {
+  test("manages sidecar lifecycle state transitions", async () => {
+    const fetchUrl = vi.fn().mockResolvedValue("http://127.0.0.1:4096")
+    const stopFn = vi.fn().mockResolvedValue(undefined)
+
+    const controller = new BaseSidecarController("local-1", "local", fetchUrl, stopFn)
+
+    expect(controller.status).toBe("idle")
+
+    const url = await controller.getUrl()
+    expect(url).toBe("http://127.0.0.1:4096")
+    expect(controller.status).toBe("ready")
+
+    await controller.stop()
+    expect(stopFn).toHaveBeenCalled()
+    expect(controller.status).toBe("stopped")
+  })
+
+  test("handles startup failures gracefully", async () => {
+    const fetchUrl = vi.fn().mockRejectedValue(new Error("Failed to start server"))
+    const stopFn = vi.fn().mockResolvedValue(undefined)
+
+    const controller = new BaseSidecarController("wsl-ubuntu", "wsl", fetchUrl, stopFn)
+
+    expect(controller.getUrl()).rejects.toThrow("Failed to start server")
+    expect(controller.status).toBe("failed")
+  })
+
+  test("createLocalSidecarController wraps local server startup and stop", async () => {
+    const stopMock = vi.fn().mockResolvedValue(undefined)
+    const startMock = vi.fn().mockResolvedValue({
+      url: "http://127.0.0.1:4096",
+      listener: { stop: stopMock },
+    })
+
+    const sidecar = createLocalSidecarController("local-main", startMock)
+    expect(sidecar.kind).toBe("local")
+    expect(sidecar.status).toBe("idle")
+
+    const url = await sidecar.getUrl()
+    expect(url).toBe("http://127.0.0.1:4096")
+    expect(sidecar.status).toBe("ready")
+
+    await sidecar.stop()
+    expect(stopMock).toHaveBeenCalled()
+    expect(sidecar.status).toBe("stopped")
+  })
+
+  test("createWslSidecarController wraps WSL server startup and stop", async () => {
+    const stopMock = vi.fn()
+    const startMock = vi.fn().mockResolvedValue({
+      url: "http://127.0.0.1:8080",
+      listener: { stop: stopMock },
+    })
+
+    const sidecar = createWslSidecarController("Ubuntu", startMock)
+    expect(sidecar.kind).toBe("wsl")
+    expect(sidecar.status).toBe("idle")
+
+    const url = await sidecar.getUrl()
+    expect(url).toBe("http://127.0.0.1:8080")
+    expect(sidecar.status).toBe("ready")
+
+    await sidecar.stop()
+    expect(stopMock).toHaveBeenCalled()
+    expect(sidecar.status).toBe("stopped")
+  })
+})
diff --git a/packages/desktop/src/main/sidecar/types.ts b/packages/desktop/src/main/sidecar/types.ts
new file mode 100644
index 000000000000..16a85b314ea6
--- /dev/null
+++ b/packages/desktop/src/main/sidecar/types.ts
@@ -0,0 +1,83 @@
+export type SidecarKind = "local" | "wsl"
+export type SidecarStatus = "idle" | "starting" | "ready" | "failed" | "stopped"
+
+export interface SidecarInstance {
+  readonly id: string
+  readonly kind: SidecarKind
+  readonly status: SidecarStatus
+  getUrl(): Promise<string | null>
+  stop(): Promise<void>
+}
+
+export class BaseSidecarController implements SidecarInstance {
+  private _status: SidecarStatus = "idle"
+
+  constructor(
+    public readonly id: string,
+    public readonly kind: SidecarKind,
+    private fetchUrl: () => Promise<string | null>,
+    private stopFn: () => Promise<void>,
+  ) {}
+
+  get status(): SidecarStatus {
+    return this._status
+  }
+
+  async getUrl(): Promise<string | null> {
+    this._status = "starting"
+    try {
+      const url = await this.fetchUrl()
+      this._status = url ? "ready" : "failed"
+      return url
+    } catch (err) {
+      this._status = "failed"
+      throw err
+    }
+  }
+
+  async stop(): Promise<void> {
+    try {
+      await this.stopFn()
+    } finally {
+      this._status = "stopped"
+    }
+  }
+}
+
+export function createLocalSidecarController(
+  id: string,
+  start: () => Promise<{ url: string; listener: { stop: () => Promise<void> } }>,
+): BaseSidecarController {
+  let stopFn = async () => {}
+  return new BaseSidecarController(
+    id,
+    "local",
+    async () => {
+      const res = await start()
+      stopFn = () => res.listener.stop()
+      return res.url
+    },
+    async () => {
+      await stopFn()
+    },
+  )
+}
+
+export function createWslSidecarController(
+  distro: string,
+  start: () => Promise<{ url: string; listener: { stop: () => void } }>,
+): BaseSidecarController {
+  let stopFn = async () => {}
+  return new BaseSidecarController(
+    distro,
+    "wsl",
+    async () => {
+      const res = await start()
+      stopFn = async () => res.listener.stop()
+      return res.url
+    },
+    async () => {
+      await stopFn()
+    },
+  )
+}