Improve doctor reachability diagnostics

package.json

@@ -25,7 +25,7 @@
     "build:app": "vite build",
     "dev": "node scripts/dev-server.mjs",
     "start": "node dist/cli.js serve",
-    "test": "tsx src/config.test.ts && tsx src/roots.test.ts && tsx src/skills.test.ts && tsx src/workspaces.test.ts && tsx src/review-checkpoints.test.ts && tsx src/oauth-store.test.ts && tsx src/cli.test.ts",
+    "test": "tsx src/config.test.ts && tsx src/roots.test.ts && tsx src/skills.test.ts && tsx src/workspaces.test.ts && tsx src/review-checkpoints.test.ts && tsx src/oauth-store.test.ts && tsx src/health.test.ts && tsx src/cli.test.ts",
     "typecheck": "tsc -p tsconfig.json --noEmit"
   },
   "keywords": [],

src/cli.ts

@@ -14,6 +14,7 @@ import {
   type DevspaceUserConfig,
 } from "./user-config.js";
 import { expandHomePath } from "./roots.js";
+import { checkEndpoint, formatEndpointHealth } from "./health.js";
 
 type Command = "serve" | "init" | "doctor" | "config" | "help" | "version";
 const require = createRequire(import.meta.url);
@@ -219,10 +220,25 @@ async function runDoctor(): Promise<void> {
 
   try {
     const config = loadConfig();
-    console.log(`Local MCP URL: http://${config.host}:${config.port}/mcp`);
-    console.log(`Public MCP URL: ${new URL("/mcp", config.publicBaseUrl).toString()}`);
+    const localMcpUrl = `http://${config.host}:${config.port}/mcp`;
+    const publicMcpUrl = new URL("/mcp", config.publicBaseUrl).toString();
+    const localHealthUrl = `http://${config.host}:${config.port}/healthz`;
+    const publicHealthUrl = new URL("/healthz", config.publicBaseUrl).toString();
+    console.log(`Local MCP URL: ${localMcpUrl}`);
+    console.log(`Public MCP URL: ${publicMcpUrl}`);
     console.log(`Allowed roots: ${config.allowedRoots.join(", ")}`);
     console.log(`Allowed hosts: ${config.allowedHosts.join(", ")}`);
+
+    const localHealth = await checkEndpoint(localHealthUrl);
+    const publicHealth = await checkEndpoint(publicHealthUrl);
+    console.log(`Local server: ${formatEndpointHealth(localHealth)}`);
+    console.log(`Public tunnel: ${formatEndpointHealth(publicHealth)}`);
+
+    if (!localHealth.ok) {
+      console.log("Action: start DevSpace with `devspace serve`.");
+    } else if (!publicHealth.ok) {
+      console.log("Action: start or repair the HTTPS tunnel, then update publicBaseUrl and reconnect the MCP client.");
+    }
   } catch (error) {
     console.log(`Config status: ${error instanceof Error ? error.message : String(error)}`);
   }

src/health.test.ts

@@ -0,0 +1,19 @@
+import assert from "node:assert/strict";
+import { checkEndpoint } from "./health.js";
+
+assert.deepEqual(
+  await checkEndpoint("http://127.0.0.1:7676/healthz", async () => new Response("ok", { status: 200 })),
+  { ok: true, status: 200 },
+);
+
+assert.deepEqual(
+  await checkEndpoint("https://stale.example.com/healthz", async () => {
+    throw new TypeError("fetch failed");
+  }),
+  { ok: false, error: "fetch failed" },
+);
+
+assert.deepEqual(
+  await checkEndpoint("https://example.com/healthz", async () => new Response("no", { status: 502 })),
+  { ok: false, status: 502, error: "HTTP 502" },
+);

src/health.ts

@@ -0,0 +1,38 @@
+export interface EndpointHealth {
+  ok: boolean;
+  status?: number;
+  error?: string;
+}
+
+type Fetch = (input: string, init?: RequestInit) => Promise<Response>;
+
+export async function checkEndpoint(
+  url: string,
+  fetcher: Fetch = fetch,
+): Promise<EndpointHealth> {
+  try {
+    const response = await fetcher(url, {
+      signal: AbortSignal.timeout(5_000),
+    });
+    if (!response.ok) {
+      return {
+        ok: false,
+        status: response.status,
+        error: `HTTP ${response.status}`,
+      };
+    }
+
+    return { ok: true, status: response.status };
+  } catch (error) {
+    return {
+      ok: false,
+      error: error instanceof Error ? error.message : String(error),
+    };
+  }
+}
+
+export function formatEndpointHealth(health: EndpointHealth): string {
+  return health.ok
+    ? `reachable (HTTP ${health.status})`
+    : `unreachable (${health.error ?? "unknown error"})`;
+}