Add Experimental Features section documenting maxTokenBudget and OpenAI-compatible endpoint

[Copilot]

Plan: Add Experimental Features Section to README

• Review the current README structure and identify the best location for the Experimental Features section
• Create an "Experimental Features" section in the README
• Move the OpenAI-compatible endpoint information from line 76 to the new section
• Add documentation for the maxTokenBudget parameter with usage example
• Ensure the section is prominently placed and easy to notice
• Review and verify the changes are accurate and well-formatted
• Address code review feedback to improve clarity
• Simplify by removing configuration example per reviewer feedback
• Remove redundant explanation to avoid duplication

Original prompt

---

This section details on the original issue you should resolve

<issue_title>maxTokenBudget parameter needs to be added in README as an experimental feature.</issue_title>
<issue_description>we’ve implemented an experimental maxTokenBudget parameter on the MCP endpoint to address token/cost control.
Users can add ?maxTokenBudget=2000 to the end of the mcp endpoint like this:
https://learn.microsoft.com/api/mcp?maxTokenBudget=2000

and the search tool responses will be truncated to meet this token budget.

There were actually another experimental feature, the openai compatible endpoint in this README.

We need to create a "experimental features" section in this README, and add both features, make it more noticable.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes maxTokenBudget parameter needs to be added in README as an experimental feature. #98

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[Copilot]

Pull request overview

This PR adds a dedicated Experimental Features section to the README to document experimental functionality that was previously scattered or not well-documented. The section consolidates information about the OpenAI-compatible endpoint and introduces documentation for the new maxTokenBudget parameter for token usage control.

• Restructures experimental feature documentation into a dedicated, prominent section
• Documents the maxTokenBudget query parameter with usage example
• Moves and expands OpenAI-compatible endpoint documentation

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Eimasogi]

@TianqiZhang Should we expand a bit more on the description to install via OpenAI? See my proposal below (but will need verification):

Connect in ChatGPT

1. You can enable Learn MCP server in ChatGPT settings: under under Settings → Connectors → Advanced Settings
2. Enable "Developer mode"
3. Go back to Connectors tab, and click "Create"
4. Enter the details for your connector, for MCP server URL, use the following: https://learn.microsoft.com/api/mcp/openai-compatible
5. For Authentication, select "No Authentication"
6. Click "Create"
7. Now you can use the OpenAI-compatible Learn MCP server endpoint with ChatGPT

[TianqiZhang]

@Eimasogi good question, I assume pointing to OpenAI's official document could make this README more maintainable than listing the steps. How about this page? https://platform.openai.com/docs/guides/developer-mode