> ## Documentation Index
> Fetch the complete documentation index at: https://enact-465fb1fc.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Key Changes

This document lists changes made to the Model Context Protocol (MCP) specification since
the previous revision, [2025-11-25](/specification/2025-11-25.md).

## Major changes

N/A

## Minor changes

1. Add `extensions` field to `ClientCapabilities` and `ServerCapabilities` to support optional [extensions](/extensions.md) beyond the core protocol.

## Other schema changes

N/A

## Governance and process updates

N/A

## Process changes

1. Formalize PR-based SEP workflow with markdown files in `seps/` directory, PR-derived numbering, sponsor responsibilities, and status management via PR labels ([SEP-1850](https://github.com/modelcontextprotocol/specification/pull/1850)).

## Full changelog

For a complete list of all changes that have been made since the last protocol revision,
[see GitHub](https://github.com/modelcontextprotocol/specification/compare/2025-11-25...draft).


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