diff --git a/nanobot/agent/verification_state.py b/nanobot/agent/verification_state.py
index 9db53c424..8c0e89024 100644
--- a/nanobot/agent/verification_state.py
+++ b/nanobot/agent/verification_state.py
@@ -51,6 +51,7 @@ _FAILURE_RE = re.compile(
     r"\bAssertionError\b|"
     r"\bFileNotFoundError\b|"
     r"\bTimeoutError\b|"
+    r"\bcommand not found\b|"
     r"\bError:\s+Command timed out\b|"
     r"\bFAILURES?\b|"
     r"\bTEST FAILED\b"
@@ -73,6 +74,7 @@ _ERROR_LINE_RE = re.compile(
     r"(?:AssertionError|FileNotFoundError|TimeoutError|ValueError|TypeError|RuntimeError)"
     r"(?::[^\n]*)?|"
     r"assert\s+[^\n]+|"
+    r"[^:\n]+:\s+line\s+\d+:\s+[^:\n]+:\s+command not found|"
     r"Error:\s+[^\n]+|"
     r"TEST FAILED[^\n]*"
     r")"
diff --git a/tests/agent/test_verification_state.py b/tests/agent/test_verification_state.py
index f06e41447..fc80017b2 100644
--- a/tests/agent/test_verification_state.py
+++ b/tests/agent/test_verification_state.py
@@ -52,3 +52,22 @@ def test_analyze_passing_test_records_success_without_feedback():
     assert analysis is not None
     assert analysis.status == "passed"
     assert append_verification_feedback("ok", analysis) == "ok"
+
+
+def test_analyze_command_not_found_as_failed_check():
+    output = """\
+STDERR:
+/usr/bin/bash: line 1: python3: command not found
+
+Exit code: 127
+"""
+
+    analysis = analyze_verification_result(
+        command="python3 - <<'PY'\nprint('quick verification')\nPY",
+        output=output,
+        exit_code=127,
+    )
+
+    assert analysis is not None
+    assert analysis.status == "failed"
+    assert any("command not found" in item for item in analysis.primary_errors)