Tool Use

Overview

ToolUse class automates the process of using tools by LLM, i.e.: - calling LLM with provided context (message sequence), - extracting tool calls requested by LLM from the response, - calling the requested tool and storing its results, - constructing message sequence with the result of call, - sending updated message sequence back to LLM.

This cycle is repeated until one of the exit criteria is met: - LLM no longer requests any tool calls, - specified maximum number of iterations is reached, - specified token usage limit is reached - there are any errors during the process (e.g. LLM requested a tool that is not available).

ToolUse class provides 3 ways to iterate through the process: - manual control - code is responsible for checking hasNextStep() and calling nextStep() in a loop, - using iterator - code uses foreach loop to iterate through the steps (internally it checks hasNextStep() and calls nextStep()), - just get final step - you only get the final step, iteration process is done internally.

Example

This example demonstrates 3 ways to use ToolUse class to allow LLM call functions if needed to answer simple math question. We provide 2 functions (add_numbers and subtract_numbers) as tools available to LLM and specify the task in plain language. The LLM is expected to call the functions in the correct order to get the final result.

```php

withMessages('Add 2455 and 3558 then subtract 4344 from the result.') ->withTools([ FunctionTool::fromCallable(add_numbers(...)), FunctionTool::fromCallable(subtract_numbers(...)), ]); // iterate until no more steps while ($toolUse->hasNextStep()) { $step = $toolUse->nextStep(); print("STEP - tokens used: " . $step->usage()->total() . "\n"); } // print final response $result = $step->response(); print("RESULT: " . $result . "\n"); // // PATTERN #2 - using iterator // echo "\nPATTERN #2 - using iterator\n"; $toolUse = (new ToolUse) ->withMessages('Add 2455 and 3558 then subtract 4344 from the result.') ->withTools([ FunctionTool::fromCallable(add_numbers(...)), FunctionTool::fromCallable(subtract_numbers(...)), ]); // iterate until no more steps foreach ($toolUse->iterator() as $step) { print("STEP - tokens used: " . $step->usage()->total() . "\n"); } // print final response $result = $toolUse->state()->currentStep()->response(); print("RESULT: " . $result . "\n"); // // PATTERN #3 - just get final step (fast forward to it) // echo "\nPATTERN #3 - get only final result\n"; $toolUse = (new ToolUse) ->withMessages('Add 2455 and 3558 then subtract 4344 from the result.') ->withTools([ FunctionTool::fromCallable(add_numbers(...)), FunctionTool::fromCallable(subtract_numbers(...)), ]); // print final response $result = $toolUse->finalStep()->response(); print("RESULT: " . $result . "\n"); ?>