From 46bf210e048a6ad7a7bddb6b97f6ee91191545eb Mon Sep 17 00:00:00 2001
From: Ty Sabs <tysabs@gmail.com>
Date: Mon, 16 Feb 2026 16:40:17 -0600
Subject: [PATCH] fix: always drop orphaned OpenAI reasoning blocks in session
 history

downgradeOpenAIReasoningBlocks was only called on model change, but
orphaned reasoning items (e.g. from an aborted stream) can exist without
a model switch and cause a 400 from the OpenAI Responses API.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 .../pi-embedded-runner.sanitize-session-history.test.ts    | 4 ++--
 src/agents/pi-embedded-runner/google.ts                    | 7 +++----
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/src/agents/pi-embedded-runner.sanitize-session-history.test.ts b/src/agents/pi-embedded-runner.sanitize-session-history.test.ts
index de10ae674..97358da85 100644
--- a/src/agents/pi-embedded-runner.sanitize-session-history.test.ts
+++ b/src/agents/pi-embedded-runner.sanitize-session-history.test.ts
@@ -204,7 +204,7 @@ describe("sanitizeSessionHistory", () => {
     expect(result.map((msg) => msg.role)).toEqual(["user"]);
   });
 
-  it("does not downgrade openai reasoning when the model has not changed", async () => {
+  it("downgrades orphaned openai reasoning even when the model has not changed", async () => {
     const sessionEntries = [
       makeModelSnapshotEntry({
         provider: "openai",
@@ -222,7 +222,7 @@ describe("sanitizeSessionHistory", () => {
       sessionManager,
     });
 
-    expect(result).toEqual(messages);
+    expect(result).toEqual([]);
   });
 
   it("downgrades openai reasoning only when the model changes", async () => {
diff --git a/src/agents/pi-embedded-runner/google.ts b/src/agents/pi-embedded-runner/google.ts
index 868db5983..0293cd5d2 100644
--- a/src/agents/pi-embedded-runner/google.ts
+++ b/src/agents/pi-embedded-runner/google.ts
@@ -457,10 +457,9 @@ export async function sanitizeSessionHistory(params: {
         modelId: params.modelId,
       })
     : false;
-  const sanitizedOpenAI =
-    isOpenAIResponsesApi && modelChanged
-      ? downgradeOpenAIReasoningBlocks(sanitizedToolResults)
-      : sanitizedToolResults;
+  const sanitizedOpenAI = isOpenAIResponsesApi
+    ? downgradeOpenAIReasoningBlocks(sanitizedToolResults)
+    : sanitizedToolResults;
 
   if (hasSnapshot && (!priorSnapshot || modelChanged)) {
     appendModelSnapshot(params.sessionManager, {