Port model field to CustomAgentConfig from reference implementation

.lastmerge

@@ -1 +1 @@
-e20f5bef125860accb30c60d1b35109371a77f16
+d0eb531e9ff58ea61f406caa9426f498f6485026

pom.xml

@@ -94,7 +94,7 @@
             reference-impl-sync workflow and deal with the subsequent
             PR.
         -->
-        <readonly-copilot-sdk-ref-impl-version-from-lastmerge-file-updated-by-reference-impl-sync>^1.0.48</readonly-copilot-sdk-ref-impl-version-from-lastmerge-file-updated-by-reference-impl-sync>
+        <readonly-copilot-sdk-ref-impl-version-from-lastmerge-file-updated-by-reference-impl-sync>^1.0.49-1</readonly-copilot-sdk-ref-impl-version-from-lastmerge-file-updated-by-reference-impl-sync>
 
     </properties>
 

scripts/codegen/package.json

@@ -7,7 +7,7 @@
     "generate:java": "tsx java.ts"
   },
   "dependencies": {
-    "@github/copilot": "^1.0.48",
+    "@github/copilot": "^1.0.49-1",
     "json-schema": "^0.4.0",
     "tsx": "^4.20.6"
   }

src/main/java/com/github/copilot/sdk/json/CustomAgentConfig.java

@@ -60,6 +60,9 @@ public class CustomAgentConfig {
     @JsonProperty("skills")
     private List<String> skills;
 
+    @JsonProperty("model")
+    private String model;
+
     /**
      * Gets the unique identifier name for this agent.
      *
@@ -255,4 +258,29 @@ public CustomAgentConfig setSkills(List<String> skills) {
         this.skills = skills;
         return this;
     }
+
+    /**
+     * Gets the model identifier for this agent.
+     *
+     * @return the model identifier (e.g. "claude-haiku-4.5"), or {@code null} if
+     *         not set
+     */
+    public String getModel() {
+        return model;
+    }
+
+    /**
+     * Sets the model identifier for this agent.
+     * <p>
+     * When set, the runtime will attempt to use this model for the agent, falling
+     * back to the parent session model if unavailable.
+     *
+     * @param model
+     *            the model identifier (e.g. "claude-haiku-4.5")
+     * @return this config for method chaining
+     */
+    public CustomAgentConfig setModel(String model) {
+        this.model = model;
+        return this;
+    }
 }