Use arrays rather than comma separated lists

Author: williammartin

pkg/github/issues.go

@@ -322,6 +322,7 @@ func listIssues(client *github.Client, t translations.TranslationHelperFunc) (to
 			),
 			mcp.WithString("state",
 				mcp.Description("Filter by state ('open', 'closed', 'all')"),
+				mcp.Enum("open", "closed", "all"),
 			),
 			mcp.WithArray("labels",
 				mcp.Description("Filter by labels"),
@@ -333,9 +334,11 @@ func listIssues(client *github.Client, t translations.TranslationHelperFunc) (to
 			),
 			mcp.WithString("sort",
 				mcp.Description("Sort by ('created', 'updated', 'comments')"),
+				mcp.Enum("created", "updated", "comments"),
 			),
 			mcp.WithString("direction",
 				mcp.Description("Sort direction ('asc', 'desc')"),
+				mcp.Enum("asc", "desc"),
 			),
 			mcp.WithString("since",
 				mcp.Description("Filter by date (ISO 8601 timestamp)"),