Hello,

As you mentioned, both

Prompt prompt = new Prompt(userText, ToolCallingChatOptions.builder().toolCallbacks(functionCallbacks).build());

and

ChatClient client = ...;
client.prompt(text).tools(tools).call();

work similarly.

However, in DefaultChatClient, if tools are already defined at the ChatClient level, any tools specified in the Prompt are ignored. This behavior can be observed in the prompt(Prompt prompt) method:

@Override
public ChatClientRequestSpec prompt(Prompt prompt) {
 Assert.notNull(prompt, "prompt cannot be null");
 DefaultChatClientRequestSpec spec = new DefaultChatClientRequestSpec(this.defaultChatClientRequest);
 // Options
 if (prompt.getOptions() != null) {
 spec.options(prompt.getOptions());
 }
 // Messages
 if (prompt.getInstructions() != null) {
 spec.messages(prompt.getInstructions());
 }
 return spec;
}

Since tools are not explicitly set from the Prompt in this method, any tools defined at the Prompt level will be ignored if ChatClient already has predefined tools.

This means that:

• If you define tools at the ChatClient level, they will always be used.
• If you want prompt-specific tools, you need to ensure that ChatClient does not have globally defined tools, or modify the client’s behavior accordingly.

You can also check this behavior in the AdvisedRequest.java (Lines 176-189)