diff --git a/CHANGELOG.md b/CHANGELOG.md
index d570d9eace..8486f2b196 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ _Living section — bullets land here as PRs merge into `release/v3.8.47` (paral
 
 - **fix(providers):** stop Antigravity connections from falsely reporting **all-accounts quota-exhausted** ([#6295](https://github.com/diegosouzapw/OmniRoute/issues/6295)) — `genericQuotaFetcher.ts::percentUsedForQuota()` ignored the `fractionReported` flag and defaulted an unreported model's `remainingPercentage` to 0, which computed as 100% used; since `convertUsageToQuotaInfo()` takes the worst-case window across a connection, a single model with no reported fraction dragged the whole account into `limitReached` and `quotaPreflight` skipped it. `percentUsedForQuota()` now returns `null` (unknown, window ignored) whenever `fractionReported === false`, before falling back to `remainingPercentage`. Regression guard: `tests/unit/generic-quota-fetcher.test.ts`.
 - **fix(providers):** grok-cli (Grok Build) now strips `reasoning_effort`/`reasoning` before forwarding the request ([#6288](https://github.com/diegosouzapw/OmniRoute/issues/6288)) — Claude Code sends `reasoning_effort` on every request (routing the Opus slot), which Grok Build's upstream chat-proxy endpoint rejects with a 400; `transformRequest()`'s existing `UNSUPPORTED` sampling-param strip list (#5273) never covered it. Regression guard: `tests/unit/grok-cli-reasoning-strip-6288.test.ts`.
+- **fix(cli):** `omniroute serve` no longer hangs silently on a readiness timeout ([#6321](https://github.com/diegosouzapw/OmniRoute/issues/6321)) — the child server's stdout was piped to `"ignore"` whenever `--log`/`OMNIROUTE_SHOW_LOG` wasn't set (the default), discarding any debug output, and `runWithSupervisor`'s `waitForServer(...).then((up) => { if (up) {...} })` had no `else` branch, so a boot that never became ready produced zero further output after "⏳ Starting server...". Stdout is now buffered alongside stderr (`ServerSupervisor.getRecentLog()`), and a timeout prints a clear diagnostic plus the buffered output instead of staying silent. Does not by itself explain why boot never completes on a given machine — see the issue for further reproduction. Regression guard: `tests/unit/cli-serve-readiness-timeout-6321.test.ts`.
 
 ### 📝 Maintenance
 
diff --git a/bin/cli/commands/serve.mjs b/bin/cli/commands/serve.mjs
index ab9d793ca3..b7abd7beeb 100644
--- a/bin/cli/commands/serve.mjs
+++ b/bin/cli/commands/serve.mjs
@@ -351,11 +351,35 @@ async function runWithSupervisor(
       if (up) {
         if (useTray) await maybeStartTray(dashboardPort, apiPort, supervisor);
         onReady(dashboardPort, apiPort, noOpen, startedAt);
+      } else {
+        reportReadinessTimeout(dashboardPort, supervisor);
       }
     });
   }
 }
 
+// #6321: waitForServer resolving `false` used to fall through silently — the CLI
+// printed the banner + "⏳ Starting server..." and then produced ZERO further
+// output forever, even though the child process may well have crashed or be
+// stuck (issue reports show the server sometimes actually comes up later, or is
+// reachable directly while the CLI still looks hung). Surface a clear diagnostic
+// plus whatever stdout/stderr the child buffered instead of going silent.
+export function reportReadinessTimeout(dashboardPort, supervisor) {
+  console.error(
+    `\n\x1b[33m⚠ Server did not respond within 60s.\x1b[0m It may still be starting, or may` +
+      ` have failed silently.`
+  );
+  console.error(`  Try:  curl -I http://localhost:${dashboardPort}/api/monitoring/health`);
+  console.error(`  Or:   rerun with \x1b[36m--log\x1b[0m to see live server output.\n`);
+
+  const recentLog = supervisor?.getRecentLog?.() ?? [];
+  if (recentLog.length) {
+    console.error("--- Recent server output ---");
+    recentLog.forEach((l) => console.error(l));
+    console.error("--- End recent output ---\n");
+  }
+}
+
 let _killTray = null;
 function killTrayIfActive() {
   if (_killTray) {
diff --git a/bin/cli/runtime/processSupervisor.mjs b/bin/cli/runtime/processSupervisor.mjs
index 63f2a9912f..1af7c9313c 100644
--- a/bin/cli/runtime/processSupervisor.mjs
+++ b/bin/cli/runtime/processSupervisor.mjs
@@ -35,22 +35,32 @@ export class ServerSupervisor {
     // heap via NODE_OPTIONS (a CLI arg would shadow/override their value). The
     // calibrated heap is already carried by env.NODE_OPTIONS either way.
     const heapArgs = buildNodeHeapArgs(process.env, this.memoryLimit);
+    // #6321: stdout used to be discarded (`"ignore"`) whenever `--log`/OMNIROUTE_SHOW_LOG
+    // wasn't set (the default) — any debug/pino output written to stdout vanished
+    // silently, so a boot that never becomes ready looked like a dead hang with zero
+    // output even at APP_LOG_LEVEL=debug. Pipe stdout too and buffer it alongside
+    // stderr so a readiness timeout can surface what the child actually printed.
     this.child = spawn("node", [...heapArgs, this.serverPath], {
       cwd: dirname(this.serverPath),
       env: this.env,
-      stdio: showLog ? "inherit" : ["ignore", "ignore", "pipe"],
+      stdio: showLog ? "inherit" : ["ignore", "pipe", "pipe"],
     });
 
     writePidFile("server", this.child.pid);
 
+    const bufferOutput = (data) => {
+      const lines = data.toString().split("\n").filter(Boolean);
+      this.crashLog.push(...lines);
+      if (this.crashLog.length > CRASH_LOG_LINES) {
+        this.crashLog = this.crashLog.slice(-CRASH_LOG_LINES);
+      }
+    };
+
+    if (this.child.stdout) {
+      this.child.stdout.on("data", bufferOutput);
+    }
     if (this.child.stderr) {
-      this.child.stderr.on("data", (data) => {
-        const lines = data.toString().split("\n").filter(Boolean);
-        this.crashLog.push(...lines);
-        if (this.crashLog.length > CRASH_LOG_LINES) {
-          this.crashLog = this.crashLog.slice(-CRASH_LOG_LINES);
-        }
-      });
+      this.child.stderr.on("data", bufferOutput);
     }
 
     this.child.on("error", (err) => this.handleExit(-1, err));
@@ -107,6 +117,12 @@ export class ServerSupervisor {
     }, delay);
   }
 
+  // #6321: exposes the buffered stdout+stderr lines so a caller (e.g. a readiness
+  // timeout) can print what the child actually said instead of silence.
+  getRecentLog() {
+    return [...this.crashLog];
+  }
+
   dumpCrashLog() {
     console.error("\n--- Server crash log ---");
     this.crashLog.forEach((l) => console.error(l));
diff --git a/tests/unit/cli-serve-readiness-timeout-6321.test.ts b/tests/unit/cli-serve-readiness-timeout-6321.test.ts
new file mode 100644
index 0000000000..5ccf73587c
--- /dev/null
+++ b/tests/unit/cli-serve-readiness-timeout-6321.test.ts
@@ -0,0 +1,64 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+
+// #6321: `omniroute serve` printed the banner + "⏳ Starting server..." then hung
+// forever with ZERO further output whenever waitForServer() timed out (resolved
+// `false`) — `runWithSupervisor`'s `.then((up) => { if (up) {...} })` had no `else`
+// branch, so a boot that never became ready was indistinguishable from a genuine
+// infinite hang, even at APP_LOG_LEVEL=debug (stdout was also being discarded —
+// see the companion assertion on ServerSupervisor.getRecentLog()).
+
+test("reportReadinessTimeout prints a diagnostic instead of staying silent (#6321)", async () => {
+  const logs: string[] = [];
+  const origErr = console.error.bind(console);
+  console.error = (...args: unknown[]) => logs.push(args.join(" "));
+
+  try {
+    const { reportReadinessTimeout } = await import("../../bin/cli/commands/serve.mjs");
+    assert.equal(
+      typeof reportReadinessTimeout,
+      "function",
+      "serve.mjs must export a readiness-timeout diagnostic handler"
+    );
+
+    const fakeSupervisor = {
+      getRecentLog: () => ["[server] booting...", "[server] waiting on migrations"],
+    };
+    reportReadinessTimeout(20128, fakeSupervisor);
+
+    const combined = logs.join("\n");
+    assert.notEqual(combined.trim(), "", "must not silently produce zero output on a timeout");
+    assert.ok(
+      combined.includes("did not respond") || combined.toLowerCase().includes("60s"),
+      `expected a clear readiness-timeout message, got:\n${combined}`
+    );
+    assert.ok(
+      combined.includes("booting") && combined.includes("migrations"),
+      "must surface the buffered server output instead of discarding it"
+    );
+  } finally {
+    console.error = origErr;
+  }
+});
+
+test("ServerSupervisor.getRecentLog() exposes buffered output for readiness diagnostics (#6321)", async () => {
+  const { ServerSupervisor } = await import("../../bin/cli/runtime/processSupervisor.mjs");
+
+  const supervisor = new ServerSupervisor({
+    serverPath: "/fake/server.js",
+    env: {},
+    maxRestarts: 0,
+  });
+
+  assert.equal(
+    typeof supervisor.getRecentLog,
+    "function",
+    "ServerSupervisor must expose getRecentLog() so callers can surface buffered output"
+  );
+
+  // Simulate lines that arrived on the child's stdout/stderr before a readiness
+  // timeout — previously stdout was piped to "ignore" and never reached crashLog.
+  supervisor.crashLog = ["stdout: server starting", "stderr: waiting for db"];
+  const recent = supervisor.getRecentLog();
+  assert.deepEqual(recent, ["stdout: server starting", "stderr: waiting for db"]);
+});