diff --git a/scripts/model_compiler.py b/scripts/model_compiler.py
index 3383eb2ca..5b6b55e90 100644
--- a/scripts/model_compiler.py
+++ b/scripts/model_compiler.py
@@ -84,9 +84,14 @@ def wait_for_external_gpu() -> None:
 
 
 def external_gpu_compile_command(command: list[str]) -> list[str]:
-  """Pin USB-GPU compilation to AGNOS' isolated CPU without changing host builds."""
+  """Pin USB-GPU compilation when AGNOS exposes the isolated CPU."""
   if sys.platform == "linux" and platform.machine() == "aarch64":
-    return ["taskset", "-c", "7", *command]
+    try:
+      available_cpus = os.sched_getaffinity(0)
+      if 7 in available_cpus:
+        return ["taskset", "-c", "7", *command]
+    except (AttributeError, OSError):
+      pass
   return command
 
 
diff --git a/starpilot/assets/tests/test_model_pipeline.py b/starpilot/assets/tests/test_model_pipeline.py
index 5e6eedd90..5b63e391d 100644
--- a/starpilot/assets/tests/test_model_pipeline.py
+++ b/starpilot/assets/tests/test_model_pipeline.py
@@ -405,10 +405,20 @@ def test_external_gpu_compile_uses_agnos_isolated_cpu(monkeypatch):
   command = ["python3", "compile_modeld.py"]
   monkeypatch.setattr(model_compiler.sys, "platform", "linux")
   monkeypatch.setattr(model_compiler.platform, "machine", lambda: "aarch64")
+  monkeypatch.setattr(model_compiler.os, "sched_getaffinity", lambda _: {7}, raising=False)
 
   assert model_compiler.external_gpu_compile_command(command) == ["taskset", "-c", "7", *command]
 
 
+def test_external_gpu_compile_skips_unavailable_agnos_cpu(monkeypatch):
+  command = ["python3", "compile_modeld.py"]
+  monkeypatch.setattr(model_compiler.sys, "platform", "linux")
+  monkeypatch.setattr(model_compiler.platform, "machine", lambda: "aarch64")
+  monkeypatch.setattr(model_compiler.os, "sched_getaffinity", lambda _: {0, 1, 2, 3}, raising=False)
+
+  assert model_compiler.external_gpu_compile_command(command) is command
+
+
 def test_external_gpu_compile_does_not_pin_other_platforms(monkeypatch):
   command = ["python3", "compile_modeld.py"]
   monkeypatch.setattr(model_compiler.sys, "platform", "darwin")