diff --git a/github-mcp-server b/github-mcp-server
new file mode 100755
index 00000000..5caad9f4
Binary files /dev/null and b/github-mcp-server differ
diff --git a/pkg/github/issues.go b/pkg/github/issues.go
index 07c76078..9efb56ac 100644
--- a/pkg/github/issues.go
+++ b/pkg/github/issues.go
@@ -442,8 +442,9 @@ func ListIssues(getClient GetClientFn, t translations.TranslationHelperFunc) (to
 			if err != nil {
 				return mcp.NewToolResultError(err.Error()), nil
 			}
-			if since != "" {
-				timestamp, err := parseISOTimestamp(since)
+			// Enhanced validation: handle empty strings, whitespace, and null values
+			if since != "" && strings.TrimSpace(since) != "" {
+				timestamp, err := parseISOTimestamp(strings.TrimSpace(since))
 				if err != nil {
 					return mcp.NewToolResultError(fmt.Sprintf("failed to list issues: %s", err.Error())), nil
 				}
@@ -912,6 +913,8 @@ type ReplaceActorsForAssignableInput struct {
 // Returns the parsed time or an error if parsing fails.
 // Example formats supported: "2023-01-15T14:30:00Z", "2023-01-15"
 func parseISOTimestamp(timestamp string) (time.Time, error) {
+	// Trim whitespace and check for empty string
+	timestamp = strings.TrimSpace(timestamp)
 	if timestamp == "" {
 		return time.Time{}, fmt.Errorf("empty timestamp")
 	}
diff --git a/pkg/github/notifications.go b/pkg/github/notifications.go
index ba9c6bc2..f9e4ff86 100644
--- a/pkg/github/notifications.go
+++ b/pkg/github/notifications.go
@@ -7,6 +7,7 @@ import (
 	"io"
 	"net/http"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/github/github-mcp-server/pkg/translations"
@@ -93,16 +94,16 @@ func ListNotifications(getClient GetClientFn, t translations.TranslationHelperFu
 			}
 
 			// Parse time parameters if provided
-			if since != "" {
-				sinceTime, err := time.Parse(time.RFC3339, since)
+			if since != "" && strings.TrimSpace(since) != "" {
+				sinceTime, err := time.Parse(time.RFC3339, strings.TrimSpace(since))
 				if err != nil {
 					return mcp.NewToolResultError(fmt.Sprintf("invalid since time format, should be RFC3339/ISO8601: %v", err)), nil
 				}
 				opts.Since = sinceTime
 			}
 
-			if before != "" {
-				beforeTime, err := time.Parse(time.RFC3339, before)
+			if before != "" && strings.TrimSpace(before) != "" {
+				beforeTime, err := time.Parse(time.RFC3339, strings.TrimSpace(before))
 				if err != nil {
 					return mcp.NewToolResultError(fmt.Sprintf("invalid before time format, should be RFC3339/ISO8601: %v", err)), nil
 				}
@@ -242,8 +243,8 @@ func MarkAllNotificationsRead(getClient GetClientFn, t translations.TranslationH
 			}
 
 			var lastReadTime time.Time
-			if lastReadAt != "" {
-				lastReadTime, err = time.Parse(time.RFC3339, lastReadAt)
+			if lastReadAt != "" && strings.TrimSpace(lastReadAt) != "" {
+				lastReadTime, err = time.Parse(time.RFC3339, strings.TrimSpace(lastReadAt))
 				if err != nil {
 					return mcp.NewToolResultError(fmt.Sprintf("invalid lastReadAt time format, should be RFC3339/ISO8601: %v", err)), nil
 				}