.Net: Document behaviour whereby KernelArguments contains arguments with incorrect types

[markwallace-microsoft]

This issue is reproducible if a KernelFunction delegate takes KernelArguments as a parameter

Consider the following request and response:

    === REQUEST ===
{
  "messages": [
    {
      "role": "user",
      "content": "What is the Semantic Kernel? Search for 5 references."
    }
  ],
  "model": "gpt-4o",
  "tools": [
    {
      "type": "function",
      "function": {
        "description": "Perform a search for content related to the specified query and return string results",
        "name": "SearchPlugin-Search",
        "parameters": {
          "type": "object",
          "required": [
            "query"
          ],
          "properties": {
            "query": {
              "description": "What to search for",
              "type": "string"
            },
            "count": {
              "description": "Number of results (default value: 2)",
              "type": "integer"
            },
            "skip": {
              "description": "Number of results to skip (default value: 0)",
              "type": "integer"
            }
          }
        },
        "strict": false
      }
    }
  ],
  "tool_choice": "auto"
}

=== RESPONSE ===
{
  "id": "chatcmpl-Ao7MjE5CzHc6gKEV204lXHLGnJG3w",
  "object": "chat.completion",
  "created": 1736508077,
  "model": "gpt-4o-2024-08-06",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": null,
        "tool_calls": [
          {
            "id": "call_FPeTqiealR6ANFmoNFb9G0iY",
            "type": "function",
            "function": {
              "name": "SearchPlugin-Search",
              "arguments": "{\"query\":\"Semantic Kernel\",\"count\":5}"
            }
          }
        ],
        "refusal": null
      },
      "logprobs": null,
      "finish_reason": "tool_calls"
    }
  ],
  "usage": {
    "prompt_tokens": 102,
    "completion_tokens": 22,
    "total_tokens": 124,
    "prompt_tokens_details": {
      "cached_tokens": 0,
      "audio_tokens": 0
    },
    "completion_tokens_details": {
      "reasoning_tokens": 0,
      "audio_tokens": 0,
      "accepted_prediction_tokens": 0,
      "rejected_prediction_tokens": 0
    }
  },
  "service_tier": "default",
  "system_fingerprint": "fp_703d4ff298"
}

Note that the tool_call.function.arguments in the response form the LLM correctly have count as an integer

The KernelFunction delegate takes KernelArguments are an input parameter e.g..

async Task<IEnumerable<string>> SearchAsync(Kernel kernel, KernelFunction function, KernelArguments arguments, CancellationToken cancellationToken)

When the delegate gets called the count argument is of type string because of this code:

// Iterate over copy of the names to avoid mutating the dictionary while enumerating it
var names = arguments.Names.ToArray();
foreach (var name in names)
{
    arguments[name] = arguments[name]?.ToString();
}

If I change the KernelFunction delegate as follows i.e.

async Task<IEnumerable<string>> SearchAsync(Kernel kernel, KernelFunction function, KernelArguments arguments, CancellationToken cancellationToken, int count = 2, int skip = 0)

The count argument is set correctly but the count argument is still in KernelArguments with the incorrect type.

Purpose of this task is to document this behaviour