diff --git a/doc/changes/unreleased.md b/doc/changes/unreleased.md
index 0552e8d46..9e5430eda 100644
--- a/doc/changes/unreleased.md
+++ b/doc/changes/unreleased.md
@@ -2,7 +2,7 @@
 
 ## Summary
 
-With #420, any GitHub repos using the PTB for **documentation** will also need to 
+With #420, any GitHub repos using the PTB for **documentation** will also need to
 reconfigure the GitHub Pages settings for each repo:
 1. Go to the affected repo's GitHub page
 2. Select 'Settings'
@@ -30,4 +30,8 @@ permissions to be increased for specific jobs.
 ## ✨ Features
 
 * [#161](https://github.com/exasol/python-toolbox/issues/161): Added support for installing extras & not using a cache to the python-environment action
-* [#408](https://github.com/exasol/python-toolbox/issues/408): Added support for GitHub runners who do not per default have pipx to use the python-environment action
\ No newline at end of file
+* [#408](https://github.com/exasol/python-toolbox/issues/408): Added support for GitHub runners who do not per default have pipx to use the python-environment action
+
+## Bugfixes
+
+* #428: Fixed detecting report coverage failures
diff --git a/exasol/toolbox/metrics.py b/exasol/toolbox/metrics.py
index 11872692f..1890e8edd 100644
--- a/exasol/toolbox/metrics.py
+++ b/exasol/toolbox/metrics.py
@@ -112,16 +112,20 @@ def total_coverage(file: Union[str, Path]) -> float:
             encoding="utf-8",
         )
         stdout = p.stdout.strip()
-        if (p.returncode == 1) and (stdout == "No data to report."):
-            print(
+
+        if p.returncode != 0:
+            message = (
                 f"The following command"
                 f" returned non-zero exit status {p.returncode}:\n"
                 f'  {" ".join(p.args)}\n'
-                f"{stdout}\n"
-                "Returning total coverage 100 %.",
-                file=sys.stderr,
+                f"{stdout}"
             )
-            return 100.0
+            if (p.returncode == 1) and (stdout == "No data to report."):
+                print(f"{message}\nReturning total coverage 100 %.", file=sys.stderr)
+                return 100.0
+            else:
+                raise RuntimeError(message)
+
         with open(report, encoding="utf-8") as r:
             data = json.load(r)
             total: float = data["totals"]["percent_covered"]
diff --git a/exasol/toolbox/nox/_metrics.py b/exasol/toolbox/nox/_metrics.py
index b662f8fd3..b5b9355e2 100644
--- a/exasol/toolbox/nox/_metrics.py
+++ b/exasol/toolbox/nox/_metrics.py
@@ -1,6 +1,8 @@
 from __future__ import annotations
 
 import argparse
+from dataclasses import dataclass
+from pathlib import Path
 
 import nox
 from nox import Session
@@ -13,6 +15,21 @@
 from noxconfig import PROJECT_CONFIG
 
 
+@dataclass
+class RequiredFile:
+    """
+    Describes a required file and the related nox task to generate this
+    file.
+    """
+
+    def __init__(self, file: Path | str, task: str):
+        self.file = file if isinstance(file, Path) else PROJECT_CONFIG.root / file
+        self.task = task
+
+    def __str__(self) -> str:
+        return f"{self.file.name} generated by `{self.task}`"
+
+
 @nox.session(name="project:report", python=False)
 def report(session: Session) -> None:
     """
@@ -45,14 +62,17 @@ def report(session: Session) -> None:
         help="Output format to produce.",
         choices=formats,
     )
-    required_files = (
-        PROJECT_CONFIG.root / ".coverage",
-        PROJECT_CONFIG.root / ".lint.txt",
-        PROJECT_CONFIG.root / ".security.json",
-    )
-    if not all(file.exists() for file in required_files):
+    required_files = [
+        RequiredFile(".coverage", "test:coverage"),
+        RequiredFile(".lint.txt", "lint:code"),
+        RequiredFile(".security.json", "lint:security"),
+    ]
+    if missing_files := [f for f in required_files if not f.file.exists()]:
+        missing = "\n- file ".join(str(f) for f in missing_files)
         session.error(
-            "Please make sure you run the `test:coverage`, `lint:security` and the `lint:code` target first"
+            "Some required files are missing.\n"
+            "Please make sure you run the related nox tasks first:\n"
+            f"{missing}"
         )
     sha1 = str(
         session.run("git", "rev-parse", "HEAD", external=True, silent=True)