Add changelog entry for Implementation description field

Author: dsp-ant

docs/specification/draft/changelog.mdx

@@ -20,10 +20,11 @@ the previous revision, [2025-06-18](/specification/2025-06-18).
 
 ## Minor changes
 
-1. Clarify that servers must respond with HTTP 403 Forbidden for invalid Origin headers in Streamable HTTP transport. (PR [#1439](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/1439))
-2. Updated the [Security Best Practices guidance](https://modelcontextprotocol.io/specification/draft/basic/security_best_practices).
-3. Clarify that input validation errors should be returned as Tool Execution Errors rather than Protocol Errors to enable model self-correction ([SEP-1303](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/1303)).
-4. Support polling SSE streams by allowing servers to disconnect at will ([SEP-1699](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/1699)).
+1. Add optional `description` field to `Implementation` interface to align with MCP registry server.json format and provide human-readable context during initialization.
+2. Clarify that servers must respond with HTTP 403 Forbidden for invalid Origin headers in Streamable HTTP transport. (PR [#1439](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/1439))
+3. Updated the [Security Best Practices guidance](https://modelcontextprotocol.io/specification/draft/basic/security_best_practices).
+4. Clarify that input validation errors should be returned as Tool Execution Errors rather than Protocol Errors to enable model self-correction ([SEP-1303](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/1303)).
+5. Support polling SSE streams by allowing servers to disconnect at will ([SEP-1699](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/1699)).
 
 ## Other schema changes