From 12a26630fc5f7ba523cf42b80ca22c9968b122c8 Mon Sep 17 00:00:00 2001
From: Synxneuos <codexbt1@gmail.com>
Date: Fri, 18 Sep 2026 01:45:56 +0530
Subject: [PATCH] fix(llm): restore id field in stateless reasoning replay
 items

PR #34027 introduced a type alias OpenAIResponsesReasoningReplay = Omit<OpenAIResponsesReasoningInput, 'id'> and built the replay object without the id field. The Azure/OpenAI Responses API requires that reasoning items carrying encrypted_content also carry a matching id, so omitting it causes HTTP 400 invalid_payload on continuation turns.

Fixes:
- Remove the Omit alias so OpenAIResponsesReasoningReplay is OpenAIResponsesReasoningInput
- Add id: reasoning.id to the replay object literal in lowerMessages
- Make id required (Schema.String) in OpenAIResponsesReasoningItem schema
- Update the join-summary test to assert id is present
- Add regression test proving the id is forwarded in the lowered input

Closes #49574
---
 .../llm/src/protocols/openai-responses.ts     |  5 ++-
 .../test/provider/openai-responses.test.ts    | 41 +++++++++++++++++++
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/packages/llm/src/protocols/openai-responses.ts b/packages/llm/src/protocols/openai-responses.ts
index 4936d31c921b..076fbb0d10dc 100644
--- a/packages/llm/src/protocols/openai-responses.ts
+++ b/packages/llm/src/protocols/openai-responses.ts
@@ -55,7 +55,7 @@ const OpenAIResponsesReasoningSummaryText = Schema.Struct({
 
 const OpenAIResponsesReasoningItem = Schema.Struct({
   type: Schema.tag("reasoning"),
-  id: Schema.optionalKey(Schema.String),
+  id: Schema.String,
   summary: Schema.Array(OpenAIResponsesReasoningSummaryText),
   encrypted_content: optionalNull(Schema.String),
 })
@@ -103,7 +103,7 @@ type OpenAIResponsesReasoningInput = {
   summary: Array<{ type: "summary_text"; text: string }>
   encrypted_content?: string | null
 }
-type OpenAIResponsesReasoningReplay = Omit<OpenAIResponsesReasoningInput, "id">
+type OpenAIResponsesReasoningReplay = OpenAIResponsesReasoningInput
 
 const OpenAIResponsesTool = Schema.Struct({
   type: Schema.tag("function"),
@@ -400,6 +400,7 @@ const lowerMessages = Effect.fn("OpenAIResponses.lowerMessages")(function* (requ
           }
           const replay = {
             type: reasoning.type,
+            id: reasoning.id,
             summary: reasoning.summary,
             encrypted_content: reasoning.encrypted_content,
           }
diff --git a/packages/llm/test/provider/openai-responses.test.ts b/packages/llm/test/provider/openai-responses.test.ts
index cd8bad51af47..97f4764a6b17 100644
--- a/packages/llm/test/provider/openai-responses.test.ts
+++ b/packages/llm/test/provider/openai-responses.test.ts
@@ -1091,6 +1091,7 @@ describe("OpenAI Responses route", () => {
       expect(prepared.body.input).toEqual([
         {
           type: "reasoning",
+          id: "rs_1",
           encrypted_content: "encrypted-state",
           summary: [
             { type: "summary_text", text: "First" },
@@ -1469,4 +1470,44 @@ describe("OpenAI Responses route", () => {
       expect(error.message).toContain("HTTP 400")
     }),
   )
+  it.effect("includes id in stateless reasoning replay item", () =>
+    Effect.gen(function* () {
+      // Regression for the bug introduced by PR #34027: the replay object
+      // built in lowerMessages explicitly omitted id via the Omit type alias,
+      // causing HTTP 400 from the Responses API when encrypted_content was
+      // present (the API requires id and encrypted_content as a matched pair).
+      const prepared = yield* LLMClient.prepare<OpenAIResponses.OpenAIResponsesBody>(
+        LLM.request({
+          id: "req_reasoning_replay_id",
+          model,
+          messages: [
+            Message.assistant([
+              {
+                type: "reasoning",
+                text: "I considered the question carefully.",
+                providerMetadata: {
+                  openai: {
+                    itemId: "rs_abc123",
+                    reasoningEncryptedContent: "encrypted-abc123",
+                  },
+                },
+              },
+            ]),
+          ],
+          providerOptions: { openai: { store: false } },
+        }),
+      )
+
+      const reasoningItem = prepared.body.input.find(
+        (item) => "type" in item && item.type === "reasoning",
+      )
+      expect(reasoningItem).toBeDefined()
+      expect(reasoningItem).toEqual({
+        type: "reasoning",
+        id: "rs_abc123",
+        encrypted_content: "encrypted-abc123",
+        summary: [{ type: "summary_text", text: "I considered the question carefully." }],
+      })
+    }),
+  )
 })