diff --git a/configs/exit_code_registry.json b/configs/exit_code_registry.json
new file mode 100644
index 00000000..84474c1e
--- /dev/null
+++ b/configs/exit_code_registry.json
@@ -0,0 +1,23 @@
+{
+  "description": "OpenAMP Foundry CLI exit code registry",
+  "codes": {
+    "0": {"meaning": "success", "description": "Command completed successfully"},
+    "1": {"meaning": "internal_error", "description": "Unexpected error during execution"},
+    "2": {"meaning": "input_error", "description": "Missing or invalid input (file not found, bad arguments)"},
+    "3": {"meaning": "validation_failure", "description": "Validation or gate check failed (data did not pass criteria)"}
+  },
+  "command_patterns": {
+    "rank": {"expected": [0, 2], "notes": "0=success, 2=missing input"},
+    "validate": {"expected": [0, 2], "notes": "0=valid, 2=missing input"},
+    "bench leakage": {"expected": [0, 2], "notes": "0=success, 2=missing input"},
+    "pilot-panel": {"expected": [0, 2], "notes": "0=success, 2=missing input"},
+    "calibration-intake": {"expected": [0, 2], "notes": "0=success, 2=missing input"},
+    "check_wave1_pass_fail.py": {"expected": [0, 2, 3], "notes": "0=all pass, 2=input error, 3=criteria fail"},
+    "validate_lab_data_return.py": {"expected": [0, 2, 3], "notes": "0=all valid, 2=input error, 3=validation fail"},
+    "validate_negative_archive.py": {"expected": [0, 2, 3], "notes": "0=all valid, 2=input error, 3=validation fail"},
+    "validate_panel_csv.py": {"expected": [0, 2, 3], "notes": "0=valid, 2=input error, 3=invalid"},
+    "check_claims.py": {"expected": [0, 3], "notes": "0=ok, 3=findings (advisory)"},
+    "check_doc_links.py": {"expected": [0, 3], "notes": "0=ok, 3=broken links found"},
+    "check_pyproject.py": {"expected": [0, 2, 3], "notes": "0=ok, 2=input error, 3=inconsistency found"}
+  }
+}
diff --git a/scripts/check_pyproject.py b/scripts/check_pyproject.py
new file mode 100644
index 00000000..f7673a7f
--- /dev/null
+++ b/scripts/check_pyproject.py
@@ -0,0 +1,93 @@
+"""Check pyproject.toml consistency with the actual package."""
+
+from __future__ import annotations
+
+import importlib
+import sys
+import tomllib
+from pathlib import Path
+
+
+def check_pyproject(pyproject_path: str = "pyproject.toml") -> dict:
+    p = Path(pyproject_path)
+    if not p.exists():
+        return {"error": f"pyproject.toml not found: {pyproject_path}"}
+
+    with p.open("rb") as f:
+        data = tomllib.load(f)
+
+    issues = []
+    checks = {}
+
+    # 1. Check Python version requirement
+    requires_python = data.get("project", {}).get("requires-python", "")
+    checks["python_requirement"] = requires_python
+
+    # 2. Check console scripts entrypoints
+    scripts = data.get("project", {}).get("scripts", {})
+    entrypoint_issues = []
+    for name, ref in scripts.items():
+        module_path = ref.split(":")[0]
+        try:
+            importlib.import_module(module_path)
+        except ImportError as e:
+            entrypoint_issues.append(f"Entrypoint '{name}' -> '{ref}': {e}")
+    if entrypoint_issues:
+        issues.extend(entrypoint_issues)
+    checks["entrypoints_ok"] = len(entrypoint_issues) == 0
+    checks["entrypoint_issues"] = entrypoint_issues
+
+    # 3. Check optional extras reference valid dependencies
+    optional_deps = data.get("project", {}).get("optional-dependencies", {})
+    extras_ok = len(optional_deps) > 0
+    checks["extras_defined"] = extras_ok
+    checks["extras_count"] = len(optional_deps)
+
+    # 4. Check project name matches package
+    pkg_name = data.get("project", {}).get("name", "")
+    # Convert hyphens to underscores for import check
+    import_name = pkg_name.replace("-", "_")
+    try:
+        importlib.import_module(import_name)
+        checks["package_importable"] = True
+    except ImportError:
+        checks["package_importable"] = False
+        issues.append(f"Package '{import_name}' cannot be imported")
+
+    return {
+        "pyproject": pyproject_path,
+        "project_name": pkg_name,
+        "python_requirement": requires_python,
+        "entrypoints": len(scripts),
+        "entrypoints_ok": checks["entrypoints_ok"],
+        "extras": len(optional_deps),
+        "issues": issues,
+        "all_ok": len(issues) == 0,
+    }
+
+
+def main() -> int:
+    import argparse
+    parser = argparse.ArgumentParser(description="Check pyproject.toml consistency")
+    parser.add_argument("--pyproject", default="pyproject.toml")
+    args = parser.parse_args()
+
+    result = check_pyproject(args.pyproject)
+    if "error" in result:
+        print(result["error"], file=sys.stderr)
+        return 2
+
+    print(f"Project: {result['project_name']}")
+    print(f"Python: {result['python_requirement']}")
+    eok = result.get("entrypoints_ok", "?")
+    print(f"Entrypoints: {result['entrypoints']}, OK: {eok}")
+    print(f"Extras: {result['extras']}")
+    print(f"All OK: {result['all_ok']}")
+    for issue in result["issues"]:
+        print(f"  ❌ {issue}")
+
+    return 0 if result["all_ok"] else 3
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/tests/test_check_pyproject.py b/tests/test_check_pyproject.py
new file mode 100644
index 00000000..8e3a391f
--- /dev/null
+++ b/tests/test_check_pyproject.py
@@ -0,0 +1,46 @@
+"""Tests for pyproject consistency checker."""
+import subprocess
+import sys
+import tomllib
+from pathlib import Path
+import pytest
+
+from scripts.check_pyproject import check_pyproject
+
+
+def test_check_runs():
+    r = check_pyproject()
+    assert "project_name" in r
+    assert r["project_name"]
+
+
+def test_python_requirement_present():
+    r = check_pyproject()
+    assert r["python_requirement"] != ""
+
+
+def test_entrypoints_defined():
+    r = check_pyproject()
+    assert r["entrypoints"] > 0
+
+
+def test_extras_defined():
+    r = check_pyproject()
+    assert r["extras"] >= 1
+
+
+def test_cli_exit():
+    r = subprocess.run([sys.executable, "scripts/check_pyproject.py"],
+                       capture_output=True, text=True, env={"PYTHONPATH": "src"})
+    assert r.returncode == 0
+
+
+def test_pyproject_is_valid_toml():
+    data = tomllib.loads(Path("pyproject.toml").read_text())
+    assert "project" in data
+    assert data["project"]["name"] == "openamp-foundry"
+
+
+def test_missing_file():
+    r = check_pyproject("/nonexistent.toml")
+    assert "error" in r
diff --git a/tests/test_exit_code_registry.py b/tests/test_exit_code_registry.py
new file mode 100644
index 00000000..fe3a8c00
--- /dev/null
+++ b/tests/test_exit_code_registry.py
@@ -0,0 +1,46 @@
+"""Tests for CLI exit code registry."""
+import json
+from pathlib import Path
+
+
+def _registry():
+    return json.loads(Path("configs/exit_code_registry.json").read_text())
+
+
+def test_file_exists():
+    assert Path("configs/exit_code_registry.json").exists()
+
+
+def test_is_valid_json():
+    r = _registry()
+    assert "codes" in r
+    assert "command_patterns" in r
+
+
+def test_exit_codes_defined():
+    r = _registry()
+    for code_str, info in r["codes"].items():
+        assert "meaning" in info
+        assert "description" in info
+        assert isinstance(int(code_str), int)
+
+
+def test_rank_has_expected_codes():
+    r = _registry()
+    assert "rank" in r["command_patterns"]
+    assert 0 in r["command_patterns"]["rank"]["expected"]
+
+
+def test_check_scripts_have_exit_3():
+    r = _registry()
+    for name, info in r["command_patterns"].items():
+        if name.endswith(".py"):
+            assert 3 in info["expected"], f"{name} should have exit code 3"
+
+
+def test_all_expected_codes_are_defined():
+    r = _registry()
+    defined = set(int(k) for k in r["codes"])
+    for name, info in r["command_patterns"].items():
+        for code in info["expected"]:
+            assert code in defined, f"{name} expects code {code} which is not defined"