Microsoft Learn MCP Server vs Ref

Microsoft Learn MCP Server

Access requires no account, key or card. No status page was found, and the FAQ does not specify numeric rate limits.

Ref

Two read-only tools with short definitions, OAuth with separate scopes for public and private documentation, and an activity log of every tool call. The API key may be passed in the URL query string, no rate limit or 429 guidance is documented, and the free allowance is 200 one-time credits.

Microsoft Learn MCP Server

1. Append ?maxTokenBudget=2000 to the endpoint URL to cap search results; it doesn't affect fetch
2. Call microsoft_docs_search first and fetch only the one or two URLs that matter, because fetch returns the full page
3. Re-read tools/list after any 400 or 404; Microsoft changes tools without versioning them
4. Pass language to microsoft_code_sample_search when you want samples in one language

Ref

1. Send the key in the x-ref-api-key header, not the ?apiKey= query parameter, so it stays out of URLs and logs
2. Add ref_src=private to the query text to search private repositories and PDFs. Searches cover public documentation only by default
3. Pass ref_read_url the exact URL from a search result. Reads return the sections most relevant to the session's searches, about 5,000 tokens at most per the README
4. Keep one MCP session per task. Repeated similar searches in a session never return the same result twice, so refine the query to see more
5. Treat tool errors as text. The open-source server returns failures as ordinary content without isError