diff --git a/src/shared/runtime-rpc-call-queue.test.ts b/src/shared/runtime-rpc-call-queue.test.ts
index adf4e2399eb..1191d14c1e6 100644
--- a/src/shared/runtime-rpc-call-queue.test.ts
+++ b/src/shared/runtime-rpc-call-queue.test.ts
@@ -37,4 +37,16 @@ describe('runtime RPC call queue', () => {
     pending.shift()?.('background-2')
     await expect(background2).resolves.toBe('background-2')
   })
+
+  it('frees the queue slot when a runtime call throws synchronously', async () => {
+    const queue = new RuntimeRpcCallQueuePool(1, 1)
+    const first = queue.enqueue('web-runtime', 'status.get', () => {
+      throw new Error('invalid stored runtime pairing')
+    })
+
+    await expect(first).rejects.toThrow('invalid stored runtime pairing')
+
+    const second = queue.enqueue('web-runtime', 'status.get', async () => 'second')
+    await expect(second).resolves.toBe('second')
+  })
 })
diff --git a/src/shared/runtime-rpc-call-queue.ts b/src/shared/runtime-rpc-call-queue.ts
index 7156685e80d..c42784e3f54 100644
--- a/src/shared/runtime-rpc-call-queue.ts
+++ b/src/shared/runtime-rpc-call-queue.ts
@@ -77,8 +77,10 @@ export class RuntimeRpcCallQueuePool {
       }
       // Why: runtime streams and worktree actions share transport capacity with
       // per-card status refreshes, so decorative calls must not stampede it.
-      void call
-        .run()
+      // Invoke through the promise chain so sync validation errors free the
+      // queue slot just like async transport failures.
+      void Promise.resolve()
+        .then(call.run)
         .then(call.resolve, call.reject)
         .finally(() => {
           queue.active = Math.max(0, queue.active - 1)