diff --git a/packages/core/src/session/generate-node.ts b/packages/core/src/session/generate-node.ts
index f26e2847c2..96804fc57f 100644
--- a/packages/core/src/session/generate-node.ts
+++ b/packages/core/src/session/generate-node.ts
@@ -74,7 +74,6 @@ export const layer = Layer.effect(
             system: contextEvent.system,
             messages: contextEvent.messages,
             tools: hookedTools,
-            toolChoice: "none",
           }),
         )
         yield* Effect.logInfo("session generation usage diagnostic", { usage: response.usage })
diff --git a/packages/core/test/session-generate.test.ts b/packages/core/test/session-generate.test.ts
index 98e7aedc0c..e78f41bdac 100644
--- a/packages/core/test/session-generate.test.ts
+++ b/packages/core/test/session-generate.test.ts
@@ -301,7 +301,7 @@ it.effect("generates from fresh settled Session context without durable mutation
       ),
     ).toEqual(["Settled partial answer"])
     expect(requests[0]?.tools).toMatchObject([{ name: "lookup", description: "Hooked lookup" }])
-    expect(requests[0]?.toolChoice).toMatchObject({ type: "none" })
+    expect(requests[0]?.toolChoice).toBeUndefined()
     expect(yield* durableState(db, sessionID)).toEqual(before)
   }),
 )