[Positioning] Write one-sentence positioning statement

Goal

A single sentence used at the top of the README, the repo About, and every external mention.

Draft to react to

Azure DocumentDB MCP Server is the Microsoft-official Model Context Protocol surface for Azure DocumentDB — designed for AI agents, secured by Microsoft Entra, and built for the local-stdio-to-production-HTTP journey. Not a replacement for the DocumentDB SDK; not a generic Mongo tool. Use it when you're putting an LLM in front of a DocumentDB workload.

Four claims, each tied to a positioning decision:

• Microsoft-official → audience + registry positioning.
• for AI agents → AI/agent-first framing.
• secured by Microsoft Entra → security as differentiator.
• Not a replacement for the SDK; not a generic Mongo tool → scope + audience.

Acceptance criteria

• Final statement is one sentence, ≤ 50 words.
• Used consistently in README, repo About, aka.ms/documentDBMCPToolkit, partner-registry submission.
• Approved by PM and a brand reviewer.

Depends on

• All four Positioning Decisions.