Merge pull request modelcontextprotocol#1817 from modelcontextprotocol/add-description-to-implementation

Add description field to Implementation interface

Author: bhosmer-ant

docs/specification/draft/basic/lifecycle.mdx

@@ -83,6 +83,7 @@ The client **MUST** initiate this phase by sending an `initialize` request conta
       "name": "ExampleClient",
       "title": "Example Client Display Name",
       "version": "1.0.0",
+      "description": "An example MCP client application",
       "icons": [
         {
           "src": "https://example.com/icon.png",
@@ -130,6 +131,7 @@ The server **MUST** respond with its own capabilities and information:
       "name": "ExampleServer",
       "title": "Example Server Display Name",
       "version": "1.0.0",
+      "description": "An example MCP server providing tools and resources",
       "icons": [
         {
           "src": "https://example.com/server-icon.svg",

docs/specification/draft/changelog.mdx

@@ -21,10 +21,11 @@ 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
 

docs/specification/draft/schema.mdx

@@ -543,6 +543,15 @@ export interface BaseMetadata {
 export interface Implementation extends BaseMetadata, Icons {
   version: string;
 
+  /**
+   * An optional human-readable description of what this implementation does.
+   *
+   * This can be used by clients or servers to provide context about their purpose
+   * and capabilities. For example, a server might describe the types of resources
+   * or tools it provides, while a client might describe its intended use case.
+   */
+  description?: string;
+
   /**
    * An optional URL of the website for this implementation.
    *