fix(openai): skip reasoning items in Responses API replay - #181
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March 19, 2026 15:17
When Store is enabled, replaying reasoning items (OfReasoning) in the Responses API input causes a validation error: Item 'rs_xxx' of type 'reasoning' was provided without its required following item. The API stores reasoning server-side and cannot pair a reconstructed reasoning item with the output item that originally followed it. The fix skips reasoning parts during replay, letting the conversation continue with visible assistant content (text / tool calls).
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…#23297) ## Problem When `Store: true` is set for OpenAI Responses API calls (the new default), multi-turn conversations with reasoning models fail on the second message: ``` stream response: bad request: Item 'rs_xxx' of type 'reasoning' was provided without its required following item. ``` The fantasy library was reconstructing full `OfReasoning` input items (with encrypted content and summary) when replaying assistant messages. The API cannot pair these reconstructed reasoning items with the output items that originally followed them because the output items are sent as plain `OfMessage` without server-side IDs. ## Fix Updates the fantasy dependency (`kylecarbs/fantasy@cj/go1.25`) to skip reasoning parts during conversation replay in `toResponsesPrompt`. With `Store` enabled, the API already has the reasoning persisted server-side — it doesn't need to be replayed in the input. Fantasy PR: charmbracelet/fantasy#181 ## Testing Adds `TestOpenAIReasoningRoundTrip` integration test that: 1. Sends a query to `o4-mini` (reasoning model with `Store: true`) 2. Verifies reasoning content is persisted 3. Sends a follow-up message — this was the failing step 4. Verifies the follow-up completes successfully Requires `OPENAI_API_KEY` env var to run.
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Thank you again @kylecarbs!
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…let#181) When Store is enabled, replaying reasoning items (OfReasoning) in the Responses API input causes a validation error: Item 'rs_xxx' of type 'reasoning' was provided without its required following item. The API stores reasoning server-side and cannot pair a reconstructed reasoning item with the output item that originally followed it. The fix skips reasoning parts during replay, letting the conversation continue with visible assistant content (text / tool calls).
taigrr
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Apr 25, 2026
…let#181) When Store is enabled, replaying reasoning items (OfReasoning) in the Responses API input causes a validation error: Item 'rs_xxx' of type 'reasoning' was provided without its required following item. The API stores reasoning server-side and cannot pair a reconstructed reasoning item with the output item that originally followed it. The fix skips reasoning parts during replay, letting the conversation continue with visible assistant content (text / tool calls).
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When Store is enabled, replaying reasoning items (OfReasoning) in the Responses API input causes a validation error:
Item 'rs_xxx' of type 'reasoning' was provided without its
required following item.
The API stores reasoning server-side and cannot pair a reconstructed reasoning item with the output item that originally followed it. The fix skips reasoning parts during replay, letting the conversation continue with visible assistant content (text / tool calls).
CONTRIBUTING.md.