Microsoft.Extensions.AI has no documentation nor Sample for Tool Usage

[JohnGalt1717]

Description

IChatClient clearly supports tool usage, but there's no documentation that I can find anywhere (I can't find real documentation for Microsoft.Extensions.AI, only the announcement) on this topic, and Copilot and Github Copilot are also clueless on how to use tools properly.

Reproduction Steps

Try and use tools with Microsoft.Extensions.AI.

Expected behavior

There should be a proper documentation page, the announcement should reference it, the nuget package should have that as the package home, and the documentation section should have explicit instructions on how to use tools.

Actual behavior

None of that is available.

Regression?

No response

Known Workarounds

🤷

Configuration

.net 9,

Other information

...

[stephentoub]

No doubt samples and docs can be improved, but you can see tool use examples in the package readme:
https://www.nuget.org/packages/Microsoft.Extensions.AI.Abstractions

in the eshop sample:
https://github.com/dotnet/eShop/blob/main/src/WebApp/Components/Chatbot/ChatState.cs#L41-L47

in the dotnet/Ai-samples, eg
https://github.com/dotnet/ai-samples/blob/main/src/microsoft-extensions-ai/ollama/OllamaExamples/ToolCalling.cs

in the eShopSupport sample, eg
https://github.com/dotnet/eShopSupport/blob/690d0815444539afb120fb9145253e990fbcfb0d/src/Backend/Api/AssistantApi.cs#L56

etc.

In short, set ChatOptions.Tools to the collection of tools you want advertised to the llm. And if you want them automatically invoked by the client when they're requested, add that support to the IChatClient, typically via UseFunctionInvocation.

[stephentoub]

cc: @LadyNaggaga

[JohnGalt1717]

The problem is that this is so undiscoverable that even with Copilot doing web searches, it still can't find it, and if it can't find it, no one else will either.

It also doesn't talk about Async, or any instructions on how to get good results from the tools (like meta data for parameters, DescriptionAttribute, JsonSchema) so one is left to stumble around in the dark.

All of the documentation should be in the .net documentation like everything else too.