Single-step completions

[mbmjertan]

Currently, every provider call handler implements tool call handling logic directly by calling the tools if the finish reason is a tool call, attaching a ToolResultMessage to the conversation and repeating a request. An example of this implementation is in the OpenAI text handler class: https://github.com/prism-php/prism/blob/7020d47b561f531e30f9a55aa7b9a81f45f657a2/src/Providers/OpenAI/Handlers/Text.php#L74C1-L103

        return match ($this->mapFinishReason($data)) {
            FinishReason::ToolCalls => $this->handleToolCalls($data, $request, $response),
            FinishReason::Stop => $this->handleStop($data, $request, $response),
            FinishReason::Length => throw new PrismException('OpenAI: max tokens excceded'),
            default => throw new PrismException('OpenAI: unknown finish reason'),
        };

However, I don't want this to happen. Some tool calls on a project I'm working on are computationally heavy and take a long time, so I want to enqueue them, block the conversation while the tools are running and continue afterwards.

Therefore, I'd like to be able to configure the handler using the builder interface in a way that Prism only wraps a single completion request, and doesn't continue, but instead just returns the Response object directly. I haven't found a lower-level interface for doing this in Prism, and by digging through the code, I don't think such a mechanism exists.

I'm open to making a PR for this if you are okay with that, but I'm not sure what the API should be.

Would this be okay? Something else?

$response = Prism::text()
    ->using(Provider::Anthropic, 'claude-3-5-sonnet-latest')
    ->withMaxSteps(2)
    ->withPrompt('What is the weather like in Paris?')
    ->withTools([$weatherTool])
    ->withoutToolExecution()
    ->asText();