diff --git a/.changeset/next-turn-models-type.md b/.changeset/next-turn-models-type.md
new file mode 100644
index 00000000..987b83d3
--- /dev/null
+++ b/.changeset/next-turn-models-type.md
@@ -0,0 +1,5 @@
+---
+'@openrouter/agent': patch
+---
+
+Type `NextTurnParamsContext.models` as `NonNullable<models.ResponsesRequest['models']>` instead of a hand-written `string[]`. It now follows the SDK's generated request type: `string[]` today, and reason-gated fallback entries once the SDK spec regenerates. With the current SDK there is no type change.
diff --git a/packages/agent/src/lib/tool-types.ts b/packages/agent/src/lib/tool-types.ts
index 90ce6671..8c10a87f 100644
--- a/packages/agent/src/lib/tool-types.ts
+++ b/packages/agent/src/lib/tool-types.ts
@@ -300,8 +300,12 @@ export type NextTurnParamsContext = {
   toolChoice: models.ResponsesRequest['toolChoice'];
   /** Current model selection */
   model: string;
-  /** Current models array */
-  models: string[];
+  /**
+   * Current models array (fallback model IDs, or reason-gated fallback
+   * entries once the SDK spec includes them). Derived from the SDK request
+   * type so it tracks the generated shape.
+   */
+  models: NonNullable<models.ResponsesRequest['models']>;
   /** Current temperature */
   temperature: number | null;
   /** Current maxOutputTokens */