fix(model-resolver): use numeric-aware version comparison for model alias resolution

src/agents/sessions/model-resolver.test.ts

@@ -4,7 +4,7 @@ import { describe, expect, it } from "vitest";
 import type { Model } from "../../llm/types.js";
 import { DEFAULT_MODEL, DEFAULT_PROVIDER } from "../defaults.js";
 import type { ModelRegistry } from "./model-registry.js";
-import { findInitialModel, restoreModelFromSession } from "./model-resolver.js";
+import { findInitialModel, parseModelPattern, restoreModelFromSession } from "./model-resolver.js";
 
 function model(provider: string, id: string): Model {
   return {
@@ -57,3 +57,15 @@ describe("model resolver fallback selection", () => {
     expect(result.model).toBe(firstAvailable);
   });
 });
+
+describe("parseModelPattern version sorting", () => {
+  it("selects the numerically highest version when aliases span double-digit minors", () => {
+    const models = [
+      model("anthropic", "claude-opus-4-9"),
+      model("anthropic", "claude-opus-4-10"),
+      model("anthropic", "claude-opus-4-11"),
+    ];
+    const result = parseModelPattern("opus", models);
+    expect(result.model?.id).toBe("claude-opus-4-11");
+  });
+});

src/agents/sessions/model-resolver.ts

@@ -116,11 +116,11 @@ function tryMatchModel(modelPattern: string, availableModels: Model[]): Model |
 
   if (aliases.length > 0) {
     // Prefer alias - if multiple aliases, pick the one that sorts highest
-    aliases.sort((a, b) => b.id.localeCompare(a.id));
+    aliases.sort((a, b) => b.id.localeCompare(a.id, undefined, { numeric: true }));
     return aliases[0];
   }
   // No alias found, pick latest dated version
-  datedVersions.sort((a, b) => b.id.localeCompare(a.id));
+  datedVersions.sort((a, b) => b.id.localeCompare(a.id, undefined, { numeric: true }));
   return datedVersions[0];
 }