fix: add missing descriptions for various tools (#213)

Fixes interoperability issues. Without descriptions, several MCP tools throw errors and refuse to parse the responses. Easiest to reproduce in mcp-probe.

---------

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Reviewed-on: https://gitea.com/gitea/gitea-mcp/pulls/213
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: Torben Nehmer <torben@nehmer.net>

operation/operation_test.go

@@ -2,8 +2,36 @@ package operation
 
 import (
 	"testing"
+
+	"gitea.com/gitea/gitea-mcp/pkg/flag"
 )
 
+// TestAllToolsHaveDescriptions ensures every registered tool sets a non-empty
+// Tool.Description. mcp-go only serializes the "description" field of a tool
+// when it is non-empty, so an omitted description makes strict MCP clients
+// (e.g. mcp-probe) reject the tools/list response with "missing field
+// `description`".
+func TestAllToolsHaveDescriptions(t *testing.T) {
+	origRO, origAllow := flag.ReadOnly, flag.AllowedTools
+	t.Cleanup(func() {
+		flag.ReadOnly, flag.AllowedTools = origRO, origAllow
+	})
+	flag.ReadOnly = false
+	flag.AllowedTools = nil
+
+	var missing []string
+	for _, d := range domainTools {
+		for _, st := range d.Tools() {
+			if st.Tool.Description == "" {
+				missing = append(missing, st.Tool.Name)
+			}
+		}
+	}
+	if len(missing) > 0 {
+		t.Errorf("tools missing a description: %v", missing)
+	}
+}
+
 func TestParseAuthToken(t *testing.T) {
 	tests := []struct {
 		name      string