Reduce MCP token usage

internal/mcp/protocol_test.go

@@ -2,6 +2,7 @@ package mcp
 
 import (
 	"encoding/json"
+	"strings"
 	"testing"
 )
 
@@ -43,6 +44,9 @@ func TestInitializeReturnsCapabilities(t *testing.T) {
 	if !ok || instructions == "" {
 		t.Fatalf("instructions missing or wrong type: %+v", parsed.Result)
 	}
+	if len(instructions) > 320 {
+		t.Fatalf("instructions too verbose: %d chars", len(instructions))
+	}
 }
 
 func TestInitializedNotificationSuppressesResponse(t *testing.T) {
@@ -74,6 +78,9 @@ func TestToolsListReturnsConcreteSchemas(t *testing.T) {
 	if parsed.Error != nil {
 		t.Fatalf("tools/list returned error: %+v", parsed.Error)
 	}
+	if len(resp) > 12000 {
+		t.Fatalf("tools/list response too large: %d bytes", len(resp))
+	}
 	tools, ok := parsed.Result["tools"].([]interface{})
 	if !ok {
 		t.Fatalf("tools not array: %+v", parsed.Result)
@@ -112,6 +119,27 @@ func TestToolsListReturnsConcreteSchemas(t *testing.T) {
 	}
 }
 
+func TestWrapToolResultDoesNotDuplicateStructuredJSON(t *testing.T) {
+	result := ProcessOutput{
+		Content:      strings.Repeat("x", 1024),
+		Mode:         "stream",
+		NewOffset:    2048,
+		ContentBytes: 1024,
+	}
+	wrapped := wrapToolResult(result)
+	if wrapped["structuredContent"] == nil {
+		t.Fatalf("structuredContent missing: %#v", wrapped)
+	}
+	content := wrapped["content"].([]map[string]any)
+	text := content[0]["text"].(string)
+	if strings.Contains(text, result.Content) {
+		t.Fatalf("content duplicated structured payload: %q", text)
+	}
+	if !strings.Contains(text, "stream output") {
+		t.Fatalf("summary text should identify output, got %q", text)
+	}
+}
+
 func TestPingReturnsEmptyObject(t *testing.T) {
 	s := &Server{}
 	req := []byte(`{"jsonrpc":"2.0","id":3,"method":"ping"}`)