diff --git a/internal/multiagent/mcp_execution_binder.go b/internal/multiagent/mcp_execution_binder.go
index 3e33b724..79fec45b 100644
--- a/internal/multiagent/mcp_execution_binder.go
+++ b/internal/multiagent/mcp_execution_binder.go
@@ -1,9 +1,13 @@
 package multiagent
 
-import "strings"
+import (
+	"strings"
+	"sync"
+)
 
 // MCPExecutionBinder maps ADK toolCallID → MCP monitor execution ID for a single agent run.
 type MCPExecutionBinder struct {
+	mu         sync.RWMutex
 	byToolCall map[string]string
 }
 
@@ -20,12 +24,17 @@ func (b *MCPExecutionBinder) Bind(toolCallID, executionID string) {
 	if tid == "" || eid == "" {
 		return
 	}
+	b.mu.Lock()
 	b.byToolCall[tid] = eid
+	b.mu.Unlock()
 }
 
 func (b *MCPExecutionBinder) ExecutionID(toolCallID string) string {
 	if b == nil {
 		return ""
 	}
-	return b.byToolCall[strings.TrimSpace(toolCallID)]
+	tid := strings.TrimSpace(toolCallID)
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	return b.byToolCall[tid]
 }