Add optional model description to ModelInfo

docs/protocol/schema.mdx

@@ -1714,6 +1714,9 @@ Information about a selectable model.
 <ResponseField name="_meta" type={"object"}>
   Extension point for implementations
 </ResponseField>
+<ResponseField name="description" type={"string | null"}>
+  Optional description of the model.
+</ResponseField>
 <ResponseField name="modelId" type={<a href="#modelid">ModelId</a>} required>
   Unique identifier for the model.
 </ResponseField>

rust/agent.rs

@@ -590,6 +590,9 @@ pub struct ModelInfo {
     pub model_id: ModelId,
     /// Human-readable name of the model.
     pub name: String,
+    /// Optional description of the model.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub description: Option<String>,
     /// Extension point for implementations
     #[serde(skip_serializing_if = "Option::is_none", rename = "_meta")]
     pub meta: Option<serde_json::Value>,

schema/schema.json

@@ -1036,6 +1036,10 @@
         "_meta": {
           "description": "Extension point for implementations"
         },
+        "description": {
+          "description": "Optional description of the model.",
+          "type": ["string", "null"]
+        },
         "modelId": {
           "$ref": "#/$defs/ModelId",
           "description": "Unique identifier for the model."

typescript/schema.ts

@@ -1369,6 +1369,10 @@ export interface ModelInfo {
   _meta?: {
     [k: string]: unknown;
   };
+  /**
+   * Optional description of the model.
+   */
+  description?: string | null;
   /**
    * Unique identifier for the model.
    */
@@ -2135,6 +2139,7 @@ export const promptCapabilitiesSchema = z.object({
 /** @internal */
 export const modelInfoSchema = z.object({
   _meta: z.record(z.unknown()).optional(),
+  description: z.string().optional().nullable(),
   modelId: z.string(),
   name: z.string(),
 });