diff --git a/codecov_cli/helpers/encoder.py b/codecov_cli/helpers/encoder.py
index 167a817e..40bf30de 100644
--- a/codecov_cli/helpers/encoder.py
+++ b/codecov_cli/helpers/encoder.py
@@ -1,13 +1,21 @@
 import re
 
+import click
+
 slug_without_subgroups_regex = re.compile(r"[^/\s]+\/[^/\s]+$")
 slug_with_subgroups_regex = re.compile(r"[^/\s]+(\/[^/\s]+)+$")
 encoded_slug_regex = re.compile(r"[^:\s]+(:::[^:\s]+)*(::::[^:\s]+){1}$")
 
 
 def encode_slug(slug: str):
+    if not slug:
+        raise click.UsageError(
+            "No slug provided. Please provide a slug using the '--slug' option (e.g. 'owner/repo')."
+        )
     if slug_with_subgroups_is_invalid(slug):
-        raise ValueError("The provided slug is invalid")
+        raise click.UsageError(
+            f"The provided slug '{slug}' is invalid. Expected format: 'owner/repo' or 'owner/subgroup/repo'."
+        )
     owner, repo = slug.rsplit("/", 1)
     encoded_owner = ":::".join(owner.split("/"))
     encoded_slug = "::::".join([encoded_owner, repo])
diff --git a/codecov_cli/services/commit/__init__.py b/codecov_cli/services/commit/__init__.py
index 23177b03..d386a67e 100644
--- a/codecov_cli/services/commit/__init__.py
+++ b/codecov_cli/services/commit/__init__.py
@@ -2,6 +2,8 @@
 import os
 import typing
 
+import click
+
 from codecov_cli import __version__ as codecov_cli_version
 from codecov_cli.helpers.config import CODECOV_INGEST_URL
 from codecov_cli.helpers.encoder import encode_slug
@@ -26,6 +28,11 @@ def create_commit_logic(
     fail_on_error: bool = False,
     args: dict = None,
 ):
+    if not slug:
+        raise click.UsageError(
+            "No slug provided. Please provide a slug using the '--slug' option (e.g. 'owner/repo'). "
+            "This is required when it cannot be auto-detected from the CI environment."
+        )
     encoded_slug = encode_slug(slug)
     sending_result = send_commit_data(
         commit_sha=commit_sha,