Add more helpful error messages

github_activity/github_activity.py

@@ -139,6 +139,7 @@ def get_activity(
     """
 
     org, repo = _parse_target(target)
+
     if repo:
         # We have org/repo
         search_query = f"repo:{org}/{repo}"
@@ -192,6 +193,10 @@ def get_activity(
             "via the GitHub CLI (`gh auth login`)."
         )
 
+    # Validate repository exists early if a specific repo was provided
+    if repo:
+        _validate_repository_exists(org, repo, auth)
+
     # Figure out dates for our query
     since_dt, since_is_git_ref = _get_datetime_and_type(org, repo, since, auth)
     until_dt, until_is_git_ref = _get_datetime_and_type(org, repo, until, auth)
@@ -867,6 +872,32 @@ def _parse_target(target):
     return org, repo
 
 
+def _validate_repository_exists(org, repo, token):
+    """Validate that a repository exists on GitHub.
+
+    Parameters
+    ----------
+    org : str
+        The organization or user name
+    repo : str
+        The repository name
+    token : str
+        GitHub authentication token
+
+    Raises
+    ------
+    ValueError
+        If the repository does not exist or is not accessible
+    """
+    auth = TokenAuth(token)
+    repo_url = f"https://api.github.com/repos/{org}/{repo}"
+    response = requests.head(repo_url, auth=auth)
+    if response.status_code == 404:
+        raise ValueError(
+            f"Repository '{org}/{repo}' not found. Please check the repository name."
+        )
+
+
 def _get_datetime_and_type(org, repo, datetime_or_git_ref, auth):
     """Return a datetime object and bool indicating if it is a git reference or
     not."""

github_activity/graphql.py

@@ -195,16 +195,42 @@ def request(self, n_pages=100, n_per_page=50):
                 auth=self.auth,
             )
             if ii_request.status_code != 200:
+                # Check for common error cases and provide helpful messages
+                if ii_request.status_code == 403:
+                    try:
+                        error_data = ii_request.json()
+                        error_message = error_data.get("message", "")
+                        if "rate limit" in error_message.lower():
+                            raise Exception(
+                                f"GitHub API rate limit exceeded. {error_message}\n"
+                                "Please wait before making more requests, or use an authentication token with higher rate limits."
+                            )
+                        else:
+                            # Generic 403 - likely a permissions issue
+                            raise Exception(
+                                f"GitHub API access forbidden. {error_message}\n"
+                                "This usually means your authentication token doesn't have the required permissions.\n"
+                                "Please check that your token has the necessary scopes for this repository."
+                            )
+                    except (ValueError, KeyError):
+                        pass
                 raise Exception(
                     "Query failed to run by returning code of {}. {}".format(
                         ii_request.status_code, ii_gql_query
                     )
                 )
-            if "errors" in ii_request.json().keys():
+            errors = ii_request.json().get("errors")
+            if errors:
+                # Check for rate limit errors in GraphQL response
+                for error in errors:
+                    if error.get("type") == "RATE_LIMITED":
+                        error_message = error.get("message", "Rate limit exceeded")
+                        raise Exception(
+                            f"GitHub API rate limit exceeded. {error_message}\n"
+                            "Please wait before making more requests, or use an authentication token with higher rate limits."
+                        )
                 raise Exception(
-                    "Query failed to run with error {}. {}".format(
-                        ii_request.json()["errors"], ii_gql_query
-                    )
+                    "Query failed to run with error {}. {}".format(errors, ii_gql_query)
                 )
             self.last_request = ii_request
 

tests/test_cli.py

@@ -132,3 +132,26 @@ def test_changelog_features(file_regression):
     assert "@dependabot" not in md_full.lower(), (
         "Bot user dependabot should not appear in output"
     )
+
+
+def test_invalid_repository_error():
+    """Test that invalid repository names produce clear error messages."""
+    from github_activity.github_activity import get_activity
+    import pytest
+
+    # Test with an invalid repository name
+    with pytest.raises(ValueError) as exc_info:
+        get_activity(
+            target="invalid-org/nonexistent-repo-12345",
+            since="2021-01-01",
+            until="2021-01-15",
+        )
+
+    # Verify the error message mentions the repository
+    error_message = str(exc_info.value)
+    assert "repository" in error_message.lower(), (
+        f"Error should mention repository, got: {error_message}"
+    )
+    assert "invalid-org/nonexistent-repo-12345" in error_message, (
+        f"Error should include the repo name, got: {error_message}"
+    )