feat(cli): live "say hi" probe for server LLMs in mcpctl status

Status was showing the server-side LLM list but not whether each one
actually serves inference. This adds a per-LLM probe that POSTs a
tiny prompt to /api/v1/llms/<name>/infer:

  messages: [{ role: 'user', content: "Say exactly the word 'hi' and nothing else." }]
  max_tokens: 8, temperature: 0

Each registered LLM gets a one-line health line:

  Server LLMs: 2 registered (probing live "say hi"...)
    fast   qwen3-thinking  ✓ "hi" 312ms
              openai → qwen3-thinking  http://litellm.../v1  key:litellm/API_KEY
    heavy  sonnet  ✗ upstream auth failed: 401
              anthropic → claude-sonnet-4-5  provider default  no key

Probes run in parallel so a single slow LLM doesn't gate the others;
each has its own 15-second timeout. JSON/YAML output gains a
\`health: { ok, ms, say?, error? }\` field per server LLM so dashboards
get the same liveness signal.

Tests: 25/25 (was 24, +1 new for the failure-path render). Workspace
suite: 2006/2006 across 149 files.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/cli/src/commands/status.ts

@@ -44,6 +44,19 @@ interface ServerLlm {
   apiKeyRef?: { name: string; key: string } | null;
 }
 
+/**
+ * Result of a live "say hi" probe against a server LLM. `ok` says we got a
+ * 200 + non-empty content back; `say` is the trimmed first 16 chars of the
+ * reply for the user to spot-check (most LLMs say "hi", a misbehaving one
+ * says "Hello! How can I assist…"). `ms` is end-to-end including TLS.
+ */
+export interface ServerLlmHealth {
+  ok: boolean;
+  ms: number;
+  say?: string;
+  error?: string;
+}
+
 export interface StatusCommandDeps {
   configDeps: Partial<ConfigLoaderDeps>;
   credentialsDeps: Partial<CredentialsDeps>;
@@ -62,6 +75,12 @@ export interface StatusCommandDeps {
    * command stays printable even when mcpd is unreachable.
    */
   fetchServerLlms: (mcpdUrl: string, token: string | null) => Promise<ServerLlm[] | null>;
+  /**
+   * Probe a single server LLM with a tiny "say hi" prompt to check it's
+   * actually serving inference. Used per-LLM in parallel after the fetch.
+   * Always resolves (never throws) so one bad LLM doesn't sink the section.
+   */
+  probeServerLlm: (mcpdUrl: string, name: string, token: string | null) => Promise<ServerLlmHealth>;
   isTTY: boolean;
 }
 
@@ -205,6 +224,85 @@ function defaultFetchServerLlms(mcpdUrl: string, token: string | null): Promise<
   });
 }
 
+/**
+ * POST a tiny "say hi" prompt to /api/v1/llms/<name>/infer and decide if
+ * the LLM actually serves inference. Returns ok=true when the response is
+ * 200 with a non-empty assistant message; otherwise ok=false with an
+ * error string suitable for one-line display.
+ */
+const PROBE_TIMEOUT_MS = 15_000;
+const PROBE_BODY = JSON.stringify({
+  messages: [{ role: 'user', content: "Say exactly the word 'hi' and nothing else." }],
+  max_tokens: 8,
+  temperature: 0,
+});
+
+function defaultProbeServerLlm(mcpdUrl: string, name: string, token: string | null): Promise<ServerLlmHealth> {
+  return new Promise((resolve) => {
+    const started = Date.now();
+    const u = new URL(`${mcpdUrl}/api/v1/llms/${encodeURIComponent(name)}/infer`);
+    const driver = u.protocol === 'https:' ? https : http;
+    const headers: Record<string, string> = {
+      'Content-Type': 'application/json',
+      Accept: 'application/json',
+      'Content-Length': String(Buffer.byteLength(PROBE_BODY)),
+    };
+    if (token !== null) headers['Authorization'] = `Bearer ${token}`;
+
+    let req: http.ClientRequest;
+    try {
+      req = driver.request({
+        hostname: u.hostname,
+        port: u.port || (u.protocol === 'https:' ? 443 : 80),
+        path: u.pathname + u.search,
+        method: 'POST',
+        headers,
+        timeout: PROBE_TIMEOUT_MS,
+      }, (res) => {
+        const chunks: Buffer[] = [];
+        res.on('data', (c: Buffer) => chunks.push(c));
+        res.on('end', () => {
+          const ms = Date.now() - started;
+          const body = Buffer.concat(chunks).toString('utf-8');
+          if ((res.statusCode ?? 0) !== 200) {
+            // Pull out just the error message if the body is JSON, else the
+            // raw status — keeps the line tidy.
+            let msg = `HTTP ${String(res.statusCode ?? 0)}`;
+            try {
+              const parsed = JSON.parse(body) as { error?: string };
+              if (typeof parsed.error === 'string') msg = parsed.error;
+            } catch { /* not JSON, fall through */ }
+            resolve({ ok: false, ms, error: msg.slice(0, 80) });
+            return;
+          }
+          let content = '';
+          try {
+            const parsed = JSON.parse(body) as {
+              choices?: Array<{ message?: { content?: string } }>;
+            };
+            content = parsed.choices?.[0]?.message?.content?.trim() ?? '';
+          } catch {
+            resolve({ ok: false, ms, error: 'invalid response body' });
+            return;
+          }
+          if (content === '') {
+            resolve({ ok: false, ms, error: 'empty content' });
+            return;
+          }
+          resolve({ ok: true, ms, say: content.slice(0, 16) });
+        });
+      });
+    } catch {
+      resolve({ ok: false, ms: Date.now() - started, error: 'request failed' });
+      return;
+    }
+    req.on('error', (e) => resolve({ ok: false, ms: Date.now() - started, error: e.message.slice(0, 80) }));
+    req.on('timeout', () => { req.destroy(); resolve({ ok: false, ms: Date.now() - started, error: 'timeout' }); });
+    req.write(PROBE_BODY);
+    req.end();
+  });
+}
+
 const SPINNER_FRAMES = ['⠋', '⠙', '⠹', '⠸', '⠼', '⠴', '⠦', '⠧', '⠇', '⠏'];
 
 const defaultDeps: StatusCommandDeps = {
@@ -217,6 +315,7 @@ const defaultDeps: StatusCommandDeps = {
   fetchModels: defaultFetchModels,
   fetchProviders: defaultFetchProviders,
   fetchServerLlms: defaultFetchServerLlms,
+  probeServerLlm: defaultProbeServerLlm,
   isTTY: process.stdout.isTTY ?? false,
 };
 
@@ -278,7 +377,7 @@ function formatProviderStatus(name: string, info: ProvidersInfo, ansi: boolean):
 }
 
 export function createStatusCommand(deps?: Partial<StatusCommandDeps>): Command {
-  const { configDeps, credentialsDeps, log, write, checkHealth, checkLlm, fetchModels, fetchProviders, fetchServerLlms, isTTY } = { ...defaultDeps, ...deps };
+  const { configDeps, credentialsDeps, log, write, checkHealth, checkLlm, fetchModels, fetchProviders, fetchServerLlms, probeServerLlm, isTTY } = { ...defaultDeps, ...deps };
 
   return new Command('status')
     .description('Show mcpctl status and connectivity')
@@ -292,14 +391,25 @@ export function createStatusCommand(deps?: Partial<StatusCommandDeps>): Command
 
       if (opts.output !== 'table') {
         // JSON/YAML: run everything in parallel, wait, output at once
+        const token = creds?.token ?? null;
         const [mcplocalReachable, mcpdReachable, llmStatus, providersInfo, serverLlms] = await Promise.all([
           checkHealth(config.mcplocalUrl),
           checkHealth(config.mcpdUrl),
           llmLabel ? checkLlm(config.mcplocalUrl) : Promise.resolve(null),
           multiProvider ? fetchProviders(config.mcplocalUrl) : Promise.resolve(null),
-          fetchServerLlms(config.mcpdUrl, creds?.token ?? null),
+          fetchServerLlms(config.mcpdUrl, token),
         ]);
 
+        // Probe each server LLM in parallel — adds 0-2 sec to JSON mode but
+        // gives consumers (scripts, dashboards) the same liveness signal as
+        // the table view.
+        const serverLlmsWithHealth = serverLlms !== null
+          ? await Promise.all(serverLlms.map(async (l) => ({
+              ...l,
+              health: await probeServerLlm(config.mcpdUrl, l.name, token),
+            })))
+          : null;
+
         const llm = llmLabel
           ? llmStatus === 'ok' ? llmLabel : `${llmLabel} (${llmStatus})`
           : null;
@@ -316,7 +426,7 @@ export function createStatusCommand(deps?: Partial<StatusCommandDeps>): Command
           llm,
           llmStatus,
           ...(providersInfo ? { providers: providersInfo } : {}),
-          ...(serverLlms !== null ? { serverLlms } : {}),
+          ...(serverLlmsWithHealth !== null ? { serverLlms: serverLlmsWithHealth } : {}),
         };
 
         log(opts.output === 'json' ? formatJson(status) : formatYaml(status));
@@ -341,11 +451,12 @@ export function createStatusCommand(deps?: Partial<StatusCommandDeps>): Command
       // Server LLMs (mcpd-managed) — fetched in parallel regardless of the
       // local-LLM config, so the section renders even on machines without
       // a configured client-side provider.
-      const serverLlmsPromise = fetchServerLlms(config.mcpdUrl, creds?.token ?? null);
+      const token = creds?.token ?? null;
+      const serverLlmsPromise = fetchServerLlms(config.mcpdUrl, token);
 
       if (!llmLabel) {
         log(`LLM:        not configured (run 'mcpctl config setup')`);
-        await renderServerLlmsSection(serverLlmsPromise, isTTY);
+        await renderServerLlmsSection(serverLlmsPromise, config.mcpdUrl, token, isTTY);
         return;
       }
 
@@ -409,17 +520,20 @@ export function createStatusCommand(deps?: Partial<StatusCommandDeps>): Command
         }
       }
 
-      await renderServerLlmsSection(serverLlmsPromise, isTTY);
+      await renderServerLlmsSection(serverLlmsPromise, config.mcpdUrl, token, isTTY);
     });
 
   /**
-   * Print a "Server LLMs:" section listing mcpd-managed Llm rows by tier.
-   * These are the rows created via `mcpctl create llm` — distinct from the
-   * mcplocal-side providers shown by the existing "LLM:" lines above. The
-   * caller awaits a pre-launched promise so this doesn't add round-trips.
+   * Print a "Server LLMs:" section listing mcpd-managed Llm rows by tier
+   * with a per-LLM "say hi" liveness probe. Distinct from the mcplocal-side
+   * providers shown by the existing "LLM:" lines above. The caller awaits a
+   * pre-launched promise so this doesn't add fetch round-trips, but the
+   * probe itself runs here (after the user has the rest of the screen).
    */
   async function renderServerLlmsSection(
     serverLlmsPromise: Promise<ServerLlm[] | null>,
+    mcpdUrl: string,
+    token: string | null,
     ansi: boolean,
   ): Promise<void> {
     const llms = await serverLlmsPromise;
@@ -433,6 +547,14 @@ export function createStatusCommand(deps?: Partial<StatusCommandDeps>): Command
       return;
     }
 
+    log(`Server LLMs: ${String(llms.length)} registered ${ansi ? DIM : ''}(probing live "say hi"...)${ansi ? RESET : ''}`);
+
+    // Run all probes in parallel — one slow LLM doesn't block the others.
+    const healthByName = new Map<string, ServerLlmHealth>();
+    await Promise.all(llms.map(async (l) => {
+      healthByName.set(l.name, await probeServerLlm(mcpdUrl, l.name, token));
+    }));
+
     const byTier = new Map<string, ServerLlm[]>();
     for (const l of llms) {
       const arr = byTier.get(l.tier) ?? [];
@@ -440,19 +562,42 @@ export function createStatusCommand(deps?: Partial<StatusCommandDeps>): Command
       byTier.set(l.tier, arr);
     }
 
-    log(`Server LLMs: ${String(llms.length)} registered`);
     // Print tiers in a stable order — fast/heavy first, then anything else.
     const tierOrder = ['fast', 'heavy', ...[...byTier.keys()].filter((t) => t !== 'fast' && t !== 'heavy').sort()];
     for (const tier of tierOrder) {
       const rows = byTier.get(tier);
       if (rows === undefined || rows.length === 0) continue;
-      const formatted = rows.map((r) => {
-        const upstream = r.url !== '' ? r.url : 'provider default';
-        const auth = r.apiKeyRef ? `key:${r.apiKeyRef.name}/${r.apiKeyRef.key}` : 'no key';
-        const line = `${r.name} (${r.type} → ${r.model})  ${upstream}  ${auth}`;
-        return ansi ? `${DIM}${line}${RESET}` : line;
-      });
+      const formatted = rows.map((r) => formatServerLlmLine(r, healthByName.get(r.name), ansi));
       log(`  ${tier.padEnd(6)} ${formatted.join('\n          ')}`);
     }
   }
 }
+
+/**
+ * Format a single server-LLM row plus its health-probe outcome on one line.
+ * Exported via module scope (not closure) so it stays cheap to test in
+ * isolation; takes \`ansi\` rather than reading a TTY at call time.
+ */
+function formatServerLlmLine(r: ServerLlm, h: ServerLlmHealth | undefined, ansi: boolean): string {
+  const upstream = r.url !== '' ? r.url : 'provider default';
+  const auth = r.apiKeyRef ? `key:${r.apiKeyRef.name}/${r.apiKeyRef.key}` : 'no key';
+  let healthStr: string;
+  if (h === undefined) {
+    healthStr = ansi ? `${DIM}? probe skipped${RESET}` : '? probe skipped';
+  } else if (h.ok) {
+    const reply = h.say !== undefined ? `"${h.say}"` : 'ok';
+    const ms = `${String(h.ms)}ms`;
+    healthStr = ansi ? `${GREEN}✓ ${reply} ${DIM}${ms}${RESET}` : `✓ ${reply} ${ms}`;
+  } else {
+    const err = h.error ?? 'failed';
+    healthStr = ansi ? `${RED}✗ ${err}${RESET}` : `✗ ${err}`;
+  }
+  const meta = `${r.type} → ${r.model}`;
+  // Two-line layout: name + health on top, dim metadata indented below.
+  // Keeps the at-a-glance signal (✓/✗) close to the LLM name.
+  const head = `${r.name}  ${healthStr}`;
+  const tail = ansi
+    ? `${DIM}${meta}  ${upstream}  ${auth}${RESET}`
+    : `${meta}  ${upstream}  ${auth}`;
+  return `${head}\n            ${tail}`;
+}

src/cli/tests/commands/status.test.ts

@@ -28,6 +28,7 @@ function baseDeps(overrides?: Partial<StatusCommandDeps>): Partial<StatusCommand
     checkHealth: async () => true,
     fetchProviders: async () => null,
     fetchServerLlms: async () => null,
+    probeServerLlm: async () => ({ ok: true, ms: 12, say: 'hi' }),
     isTTY: false,
     ...overrides,
   };
@@ -210,14 +211,33 @@ describe('status command', () => {
         { id: 'l1', name: 'qwen3-thinking', type: 'openai', model: 'qwen3-thinking', tier: 'fast', url: 'http://x:4000/v1', apiKeyRef: { name: 'litellm', key: 'API_KEY' } },
         { id: 'l2', name: 'sonnet', type: 'anthropic', model: 'claude-sonnet-4-5', tier: 'heavy', url: '', apiKeyRef: null },
       ],
+      probeServerLlm: async () => ({ ok: true, ms: 42, say: 'hi' }),
     }));
     await cmd.parseAsync([], { from: 'user' });
     const out = output.join('\n');
     expect(out).toContain('Server LLMs: 2 registered');
-    expect(out).toContain('qwen3-thinking (openai → qwen3-thinking)');
-    expect(out).toContain('sonnet (anthropic → claude-sonnet-4-5)');
+    expect(out).toContain('qwen3-thinking');
+    expect(out).toContain('openai → qwen3-thinking');
+    expect(out).toContain('sonnet');
+    expect(out).toContain('anthropic → claude-sonnet-4-5');
     expect(out).toMatch(/fast\s+qwen3-thinking/);
     expect(out).toMatch(/heavy\s+sonnet/);
+    // Health probe result rendered for each LLM
+    expect(out).toContain('✓ "hi" 42ms');
+  });
+
+  it('renders a failed "say hi" probe with the error message', async () => {
+    const cmd = createStatusCommand(baseDeps({
+      fetchServerLlms: async () => [
+        { id: 'l1', name: 'broken', type: 'openai', model: 'gpt-4o', tier: 'fast', url: 'http://x', apiKeyRef: null },
+      ],
+      probeServerLlm: async () => ({ ok: false, ms: 5000, error: 'upstream auth failed: 401' }),
+    }));
+    await cmd.parseAsync([], { from: 'user' });
+    const out = output.join('\n');
+    expect(out).toContain('Server LLMs: 1 registered');
+    expect(out).toContain('broken');
+    expect(out).toContain('✗ upstream auth failed: 401');
   });
 
   it('renders "none registered" when mcpd has no Llm rows', async () => {
@@ -254,13 +274,22 @@ describe('status command', () => {
     expect(capturedToken).toBeNull();
   });
 
-  it('includes serverLlms in JSON output', async () => {
+  it('includes serverLlms with probed health in JSON output', async () => {
     const llms = [
       { id: 'l1', name: 'qwen3-thinking', type: 'openai', model: 'qwen3-thinking', tier: 'fast', url: 'http://x', apiKeyRef: null },
     ];
-    const cmd = createStatusCommand(baseDeps({ fetchServerLlms: async () => llms }));
+    const cmd = createStatusCommand(baseDeps({
+      fetchServerLlms: async () => llms,
+      probeServerLlm: async () => ({ ok: true, ms: 99, say: 'hi' }),
+    }));
     await cmd.parseAsync(['-o', 'json'], { from: 'user' });
-    const parsed = JSON.parse(output[0]) as { serverLlms?: typeof llms };
-    expect(parsed.serverLlms).toEqual(llms);
+    const parsed = JSON.parse(output[0]) as {
+      serverLlms?: Array<typeof llms[number] & { health: { ok: boolean; ms: number; say?: string } }>;
+    };
+    expect(parsed.serverLlms).toHaveLength(1);
+    expect(parsed.serverLlms![0]).toMatchObject({
+      name: 'qwen3-thinking',
+      health: { ok: true, ms: 99, say: 'hi' },
+    });
   });
 });