fix(ai): keep stateless hosted tool results and tolerate WS keepalives

Two stream/parse fidelity fixes from the openai-node behavioral audit:

- store:false hosted tool results with json/text/error payloads emitted
  no input items at all, so the tool outcome disappeared from the
  conversation. Degrade them to their text form in the synthetic user
  message alongside the existing content path.
- WebSocket keepalive frames arriving before response.created tripped
  the channel ordering guard and failed the exchange. Treat them as
  stateless pass-through frames.

packages/ai/src/protocols/open-responses-channel.ts

@@ -112,6 +112,8 @@ const driver = (options: Options, body: string): WebSocketChannelDriver => {
           responseID = created
           return { type: "frame", frame }
         }
+        // Keepalives carry no response state and may arrive before response.created.
+        if (event.type === "keepalive") return { type: "frame", frame }
         if (!responseID)
           return yield* ProviderShared.eventError(
             options.id,

packages/ai/src/protocols/open-responses.ts

@@ -582,8 +582,13 @@ const lowerMessages = Effect.fn("OpenResponses.lowerMessages")(function* (reques
           const id = itemID(part.providerMetadata, providerMetadataKey)
           if (store !== false && id && !hostedToolReferences.has(id))
             input.push({ type: "item_reference", id })
-          if (store === false && part.result.type === "content") {
-            const content: ReadonlyArray<Content> = part.result.value
+          if (store === false) {
+            // The server is not storing this exchange, so the tool outcome has to
+            // travel in the input. Non-content results degrade to their text form.
+            const content: ReadonlyArray<Content> =
+              part.result.type === "content"
+                ? part.result.value
+                : [{ type: "text", text: ProviderShared.toolResultText(part) }]
             input.push({
               role: "user",
               content: yield* Effect.forEach(content, (item) =>

packages/ai/test/provider/openai-responses.test.ts

@@ -394,6 +394,38 @@ describe("OpenAI Responses route", () => {
     }),
   )
 
+  it.effect("tolerates keepalive frames before response.created", () =>
+    Effect.gen(function* () {
+      const webSocket = WebSocketTransport.makeDirect({
+        open: () =>
+          Effect.succeed({
+            sendText: () => Effect.void,
+            messages: Stream.fromArray([
+              ProviderShared.encodeJson({ type: "keepalive", sequence_number: 0 }),
+              ProviderShared.encodeJson({ type: "response.created", response: { id: "resp_alive" } }),
+              ProviderShared.encodeJson({
+                type: "response.completed",
+                response: { id: "resp_alive", usage: { input_tokens: 1, output_tokens: 1 } },
+              }),
+            ]),
+            close: Effect.void,
+          }),
+      })
+      const deps = Layer.succeed(
+        RequestExecutor.Service,
+        RequestExecutor.Service.of({ execute: () => Effect.die("unexpected HTTP request") }),
+      )
+      const model = OpenAI.configure({ baseURL: "https://api.openai.test/v1/", apiKey: "test" }).responses(
+        "gpt-4.1-mini",
+      )
+
+      const response = yield* LLMClient.generate(LLM.request({ model, prompt: "hi" }), { webSocket }).pipe(
+        Effect.provide(LLMClient.layer.pipe(Layer.provide(deps))),
+      )
+      expect(response.finishReason?.normalized).toBe("stop")
+    }),
+  )
+
   it.effect("continues a tool call with only the new tool output", () =>
     Effect.gen(function* () {
       const firstRequest = {
@@ -2272,6 +2304,44 @@ describe("OpenAI Responses route", () => {
     }),
   )
 
+  it.effect("continues stateless hosted tool results with their text form", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model,
+          messages: [
+            Message.user("Search."),
+            Message.assistant([
+              ToolCallPart.make({
+                id: "ws_1",
+                name: "web_search",
+                input: { query: "effect 4" },
+                providerExecuted: true,
+                providerMetadata: { openai: { itemId: "ws_1" } },
+              }),
+              {
+                type: "tool-result",
+                id: "ws_1",
+                name: "web_search",
+                result: { type: "json", value: { type: "web_search_call", id: "ws_1", status: "completed" } },
+                providerExecuted: true,
+                providerMetadata: { openai: { itemId: "ws_1" } },
+              },
+            ]),
+            Message.user("Continue."),
+          ],
+          providerOptions: { store: false },
+        }),
+      )
+
+      expect(prepared.body.input).toEqual([
+        { role: "user", content: [{ type: "input_text", text: "Search." }] },
+        { role: "user", content: [{ type: "input_text", text: '{"type":"web_search_call","id":"ws_1","status":"completed"}' }] },
+        { role: "user", content: [{ type: "input_text", text: "Continue." }] },
+      ])
+    }),
+  )
+
   it.effect("continues stateless hosted image generation with the generated image", () =>
     Effect.gen(function* () {
       const imageTool = OpenAI.imageGeneration({ action: "edit" })