diff --git a/tests/test_missing_file_errors.py b/tests/test_missing_file_errors.py
new file mode 100644
index 00000000..f6edf3f9
--- /dev/null
+++ b/tests/test_missing_file_errors.py
@@ -0,0 +1,105 @@
+"""Tests for missing-file error behavior across CLI commands.
+
+Verifies that commands fail with clear, actionable messages
+when required input files are missing.
+"""
+
+import subprocess
+import sys
+
+import pytest
+
+ROOT = "."
+
+
+def _run(*args: str) -> subprocess.CompletedProcess:
+    return subprocess.run(
+        [sys.executable, "-m", "openamp_foundry.cli", *args],
+        capture_output=True, text=True,
+        env={"PYTHONPATH": "src"},
+        cwd=ROOT,
+    )
+
+
+def _run_script(script: str, *args: str) -> subprocess.CompletedProcess:
+    return subprocess.run(
+        [sys.executable, script, *args],
+        capture_output=True, text=True,
+        env={"PYTHONPATH": "src"},
+        cwd=ROOT,
+    )
+
+
+class TestRank:
+    def test_missing_candidates(self):
+        r = _run("rank", "--candidates", "/nonexistent.csv", "--out", "/tmp/out.jsonl")
+        assert r.returncode != 0
+
+    def test_missing_config(self):
+        r = _run("rank", "--candidates", "examples/sequences/demo_candidates.csv",
+                 "--config", "/nonexistent.yaml", "--out", "/tmp/out.jsonl")
+        assert r.returncode != 0
+
+
+class TestValidate:
+    def test_missing_certificate(self):
+        r = _run("validate", "--certificate", "/nonexistent.json",
+                 "--schema", "schemas/candidate.schema.json")
+        assert r.returncode != 0
+        assert "nonexistent" in r.stdout.lower() or "nonexistent" in r.stderr.lower()
+
+    def test_missing_schema(self):
+        r = _run("validate", "--certificate", "schemas/candidate.schema.json",
+                 "--schema", "/nonexistent.json")
+        assert r.returncode != 0
+
+
+class TestBench:
+    def test_leakage_missing_candidates(self):
+        r = _run("bench", "leakage", "--candidates", "/nonexistent.csv",
+                 "--references", "examples/known_reference/demo_known_amps.csv")
+        assert r.returncode != 0
+
+
+class TestPilotPanel:
+    def test_missing_ranked(self):
+        r = _run("pilot-panel", "--ranked", "/nonexistent.jsonl", "--out", "/tmp/p.csv")
+        assert r.returncode != 0
+
+
+class TestCalibrationIntake:
+    def test_missing_predictions(self):
+        r = _run("calibration-intake", "--predictions", "/nonexistent.csv",
+                 "--results-dir", "examples/lab_results", "--panel-name", "test")
+        assert r.returncode != 0
+
+
+class TestRankMissingRefs:
+    def test_missing_references(self):
+        r = _run("rank", "--candidates", "/nonexistent.csv",
+                 "--references", "/nonexistent.csv", "--out", "/tmp/out.jsonl")
+        assert r.returncode != 0
+
+
+class TestPassFailCheck:
+    def test_missing_results_dir(self):
+        r = _run_script("scripts/check_wave1_pass_fail.py", "--results-dir", "/nonexistent")
+        assert r.returncode == 2
+
+    def test_missing_criteria(self):
+        r = _run_script("scripts/check_wave1_pass_fail.py",
+                        "--results-dir", "examples/lab_results",
+                        "--criteria", "/nonexistent.yaml")
+        assert r.returncode == 2
+
+
+class TestValidateLabData:
+    def test_missing_dir(self):
+        r = _run_script("scripts/validate_lab_data_return.py", "--results-dir", "/nonexistent")
+        assert r.returncode == 2
+
+
+class TestNegativeArchive:
+    def test_missing_archive(self):
+        r = _run_script("scripts/validate_negative_archive.py", "--archive", "/nonexistent.csv")
+        assert "error" in r.stdout.lower() or r.returncode != 0