diff --git a/src/cli/runtime-client.test.ts b/src/cli/runtime-client.test.ts
index d3d6917b54d..ecb5030a73b 100644
--- a/src/cli/runtime-client.test.ts
+++ b/src/cli/runtime-client.test.ts
@@ -348,6 +348,56 @@ describe.skipIf(process.platform === 'win32')('RuntimeClient', () => {
     })
   })
 
+  // STA-3969: the poll carried the earlier reason forward with `?? lastReason`, so a runtime
+  // that RECOVERED mid-wait was still reported unreachable at the timeout -- a stale negative
+  // presented as the current diagnosis.
+  it('openOrca stops reporting a runtime unreachable once it answers again', async () => {
+    const userDataPath = mkdtempSync(join(tmpdir(), 'orca-runtime-client-'))
+    const endpoint = join(userDataPath, 'runtime.sock')
+    const server = createServer((socket) => {
+      sockets.add(socket)
+      socket.once('close', () => sockets.delete(socket))
+      socket.once('data', (data) => {
+        const request = JSON.parse(String(data).trim()) as { id: string }
+        socket.write(
+          `${JSON.stringify({
+            id: request.id,
+            ok: true,
+            result: {
+              runtimeId: 'runtime-1',
+              rendererGraphEpoch: 0,
+              graphStatus: 'ready',
+              authoritativeWindowId: 0,
+              desktopWindowStatus: 'initializing',
+              liveTabCount: 0,
+              liveLeafCount: 0
+            },
+            _meta: { runtimeId: 'runtime-1' }
+          })}\n`
+        )
+      })
+    })
+    servers.add(server)
+    await new Promise<void>((resolve) => server.listen(endpoint, resolve))
+    // Starts pointed at an endpoint nothing serves, then recovers onto the live one.
+    writeMetadata(userDataPath, join(userDataPath, 'never-listened.sock'), 'token', process.pid)
+    vi.mocked(launchOrcaApp).mockImplementationOnce(() => {
+      writeMetadata(userDataPath, endpoint, 'token', process.pid)
+    })
+
+    const client = new RuntimeClient(userDataPath, 100)
+
+    const failure = await client.openOrca(1_000).then(
+      () => null,
+      (error: unknown) => error as { code: string; message: string; data?: unknown }
+    )
+    expect(failure?.code).toBe('runtime_open_timeout')
+    expect(failure?.message).not.toContain('unreachable')
+    expect(failure?.data).toBeUndefined()
+    // The second timeout case: answers all the way through, just no window.
+    expect(failure?.message).toContain('is responding and still running headlessly')
+  })
+
   it('openOrca waits for a reachable headless runtime to expose a desktop window', async () => {
     const userDataPath = mkdtempSync(join(tmpdir(), 'orca-runtime-client-'))
     const endpoint = join(userDataPath, 'runtime.sock')
diff --git a/src/cli/runtime/client.ts b/src/cli/runtime/client.ts
index 92afd58c35e..a3043139bb3 100644
--- a/src/cli/runtime/client.ts
+++ b/src/cli/runtime/client.ts
@@ -264,6 +264,7 @@ export class RuntimeClient {
 
     const startedAt = Date.now()
     let lastReason = initial.result.runtime.unreachableReason
+    let runtimeAnswered = initial.result.runtime.reachable
     while (Date.now() - startedAt < timeoutMs) {
       const status = await this.getCliStatus()
       if (status.result.app.desktopWindowStatus === 'blocked') {
@@ -272,18 +273,30 @@ export class RuntimeClient {
       if (status.result.app.desktopWindowStatus === 'available') {
         return status
       }
-      lastReason = status.result.runtime.unreachableReason ?? lastReason
+      // Why (STA-3969): a runtime that answered is reachable NOW, so carrying the earlier
+      // reason forward would report a stale negative -- naming an endpoint it no longer
+      // uses -- as the current diagnosis.
+      runtimeAnswered = status.result.runtime.reachable
+      lastReason = runtimeAnswered
+        ? undefined
+        : (status.result.runtime.unreachableReason ?? lastReason)
       await delay(250)
     }
 
     // Why: STA-3969 — this loop polls getCliStatus, so when the runtime is
     // unreachable it burns the whole timeout and then reported only that it timed
     // out. Carry the reachability failure the poll already diagnosed.
+    // Why: the two timeouts are different failures. One never got an answer from the
+    // runtime; the other got answers the whole time and no window with them -- telling that
+    // user the runtime "may" be running headlessly understates what the poll already proved.
+    const timeoutDetail = lastReason
+      ? `: the Orca app process is running but its runtime is unreachable. ${lastReason.message}`
+      : runtimeAnswered
+        ? '. The Orca runtime is responding and still running headlessly; it did not open a window in time.'
+        : '. The runtime may still be running headlessly.'
     throw new RuntimeClientError(
       'runtime_open_timeout',
-      lastReason
-        ? `Timed out waiting for an Orca desktop window: the Orca app process is running but its runtime is unreachable. ${lastReason.message}`
-        : 'Timed out waiting for an Orca desktop window. The runtime may still be running headlessly.',
+      `Timed out waiting for an Orca desktop window${timeoutDetail}`,
       lastReason ? { unreachableReason: lastReason } : undefined
     )
   }