diff --git a/core/src/main/java/com/google/adk/tools/BaseToolset.java b/core/src/main/java/com/google/adk/tools/BaseToolset.java
index c7620f91..46c9f882 100644
--- a/core/src/main/java/com/google/adk/tools/BaseToolset.java
+++ b/core/src/main/java/com/google/adk/tools/BaseToolset.java
@@ -2,7 +2,7 @@
 
 import com.google.adk.agents.ReadonlyContext;
 import io.reactivex.rxjava3.core.Flowable;
-import java.util.List;
+import java.util.Collection;
 import java.util.Optional;
 
 /** Base interface for toolsets. */
@@ -31,7 +31,7 @@ public interface BaseToolset extends AutoCloseable {
    * list of tools of if testing against the given ToolPredicate returns true (otherwise false).
    *
    * @param tool The tool to check.
-   * @param toolFilter An Optional containing either a ToolPredicate or a List of tool names.
+   * @param toolFilter An Optional containing either a ToolPredicate or a Collection of tool names.
    * @param readonlyContext The current context.
    * @return true if the tool is selected.
    */
@@ -44,9 +44,9 @@ default boolean isToolSelected(
     if (filter instanceof ToolPredicate toolPredicate) {
       return toolPredicate.test(tool, readonlyContext);
     }
-    if (filter instanceof List) {
+    if (filter instanceof Collection) {
       @SuppressWarnings("unchecked")
-      List<String> toolNames = (List<String>) filter;
+      Collection<String> toolNames = (Collection<String>) filter;
       return toolNames.contains(tool.name());
     }
     return false;
diff --git a/core/src/main/java/com/google/adk/tools/mcp/McpToolset.java b/core/src/main/java/com/google/adk/tools/mcp/McpToolset.java
index 0ada2027..25df3b5d 100644
--- a/core/src/main/java/com/google/adk/tools/mcp/McpToolset.java
+++ b/core/src/main/java/com/google/adk/tools/mcp/McpToolset.java
@@ -89,7 +89,7 @@ public McpToolset(SseServerParameters connectionParams, ObjectMapper objectMappe
    *
    * @param connectionParams The local server connection parameters to the MCP server.
    * @param objectMapper An ObjectMapper instance for parsing schemas.
-   * @param toolFilter An Optional containing either a ToolPredicate or a List of tool names.
+   * @param toolFilter An Optional containing either a ToolPredicate or a Collection of tool names.
    */
   public McpToolset(
       ServerParameters connectionParams, ObjectMapper objectMapper, Optional<Object> toolFilter) {