diff --git a/CHANGELOG.md b/CHANGELOG.md
index d02ab7c32e8..5058efea727 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ Docs: https://docs.openclaw.ai
 ### Fixes
 
 - Control UI/cron: keep the runtime-only `last` delivery sentinel from being materialized into persisted cron delivery and failure-alert channel configs when jobs are created or edited. (#68829) Thanks @tianhaocui.
+- OpenAI/Responses: strip orphaned reasoning blocks before outbound Responses API calls so compacted or restored histories no longer fail on standalone reasoning items. (#55787) Thanks @suboss87.
 
 ## 2026.4.19-beta.2
 
diff --git a/src/agents/pi-embedded-helpers/openai.ts b/src/agents/pi-embedded-helpers/openai.ts
index 17cfa45e354..c96151b18b6 100644
--- a/src/agents/pi-embedded-helpers/openai.ts
+++ b/src/agents/pi-embedded-helpers/openai.ts
@@ -207,6 +207,7 @@ export function downgradeOpenAIFunctionCallReasoningPairs(
  * is incomplete, drop the block to keep history usable.
  */
 export function downgradeOpenAIReasoningBlocks(messages: AgentMessage[]): AgentMessage[] {
+  let anyChanged = false;
   const out: AgentMessage[] = [];
 
   for (const msg of messages) {
@@ -259,6 +260,7 @@ export function downgradeOpenAIReasoningBlocks(messages: AgentMessage[]): AgentM
       continue;
     }
 
+    anyChanged = true;
     if (nextContent.length === 0) {
       continue;
     }
@@ -266,5 +268,5 @@ export function downgradeOpenAIReasoningBlocks(messages: AgentMessage[]): AgentM
     out.push({ ...assistantMsg, content: nextContent } as AgentMessage);
   }
 
-  return out;
+  return anyChanged ? out : messages;
 }
diff --git a/src/agents/pi-embedded-runner/run/attempt.ts b/src/agents/pi-embedded-runner/run/attempt.ts
index ea465367a33..ef5f969fa9a 100644
--- a/src/agents/pi-embedded-runner/run/attempt.ts
+++ b/src/agents/pi-embedded-runner/run/attempt.ts
@@ -72,6 +72,7 @@ import {
 import type { EmbeddedContextFile } from "../../pi-embedded-helpers.js";
 import {
   downgradeOpenAIFunctionCallReasoningPairs,
+  downgradeOpenAIReasoningBlocks,
   isCloudCodeAssistFormatError,
   resolveBootstrapMaxChars,
   resolveBootstrapPromptTruncationWarningMode,
@@ -1367,7 +1368,10 @@ export async function runEmbeddedAttempt(
           if (!Array.isArray(messages)) {
             return inner(model, context, options);
           }
-          const sanitized = downgradeOpenAIFunctionCallReasoningPairs(messages as AgentMessage[]);
+          // Strip orphaned reasoning blocks first, then fix function-call
+          // pairing — matches the call order in google.ts.
+          const reasoningSanitized = downgradeOpenAIReasoningBlocks(messages as AgentMessage[]);
+          const sanitized = downgradeOpenAIFunctionCallReasoningPairs(reasoningSanitized);
           if (sanitized === messages) {
             return inner(model, context, options);
           }