[Google AI Overview at the query, signed out and incognito (operator defaults of 2026-10-01 and 2026-10-14), 2026-10-29. The paste is the Overview expanded (the 'AI Mode Conversation' view, with the source cards that follow the answer); the 'You said' line carries the query twice, run together, and is given once here. Inline links are Google redirect URLs, kept as pasted.]

[QUERENT] OLMoTrace

[SYSTEM] [OLMoTrace](https://www.google.com/goto?url=CAESWgHrOzAVoVYHLgJxMVIjxyaZx7wDArKB6jxCb1tOprJFofLF9_o_Lr6foJNzJ2skLWhN04W7o7uFmFuQkrV4xPmu8JuLWWjcOIm7uniqJ_3AgD9QQJlTrCUJTQ) is an open-source system developed by the Allen Institute for Artificial Intelligence (Ai2) that traces language model outputs back to their multi-trillion-token training datasets in real time. [[1](https://www.google.com/goto?url=CAESWgHrOzAVoVYHLgJxMVIjxyaZx7wDArKB6jxCb1tOprJFofLF9_o_Lr6foJNzJ2skLWhN04W7o7uFmFuQkrV4xPmu8JuLWWjcOIm7uniqJ_3AgD9QQJlTrCUJTQ), [2](https://www.google.com/goto?url=CAESWAHrOzAVIeW0Bh-S4A2VvhIfG4x5GI442H2AG7c4YT-P8qSUHih41gNA2d_u0ez62uyi0CLMCuDxp107lq0nGROUCWBCMy5JoGWd2CZ7_vNcWWCs3Lu2iFg)]
How It Works

* Real-Time Tracing: After a model generates a response in the Ai2 Playground, users can click the Show OLMoTrace button to highlight verbatim spans of text. [[1](https://www.google.com/goto?url=CAESkgEB6zswFSw37mmS0ky2JdwMbluTG9bXw6YrEyY7-RDR3C6gpGJF1AjuVzgdHaMhPrwWEs6-CqOPaBUaJmKtgKhm0K6DY4dgamujc7BlSKs3Q7zgBXwn4p50GiZOmvHB7LP_ros68_TLow3I8e5BC6voQvexCU7B9RANXq30erTczX0PJp4Eoot_gOSfIdL-s64rEQ), [2](https://www.google.com/goto?url=CAESWgHrOzAVoVYHLgJxMVIjxyaZx7wDArKB6jxCb1tOprJFofLF9_o_Lr6foJNzJ2skLWhN04W7o7uFmFuQkrV4xPmu8JuLWWjcOIm7uniqJ_3AgD9QQJlTrCUJTQ)]
* Source Retrieval: The tool matches output segments against training corpora (such as the Dolma datasets) and ranks up to 10 context documents using BM25 and unigram probabilities. [[1](https://www.google.com/goto?url=CAESaQHrOzAVV_6J7u0vQR70ckMfNhiCogECpGpN15fGLDhAZkGzPPDHW94cWHDI3yvNEPPIeJCWECt_JJh8NwwM53Wiwyx94U6j_n8S84uLcd-yOdbxGgO2_8_63OmgYRHsjdzAlH-iXL3LIA), [2](https://www.google.com/goto?url=CAESWgHrOzAVoVYHLgJxMVIjxyaZx7wDArKB6jxCb1tOprJFofLF9_o_Lr6foJNzJ2skLWhN04W7o7uFmFuQkrV4xPmu8JuLWWjcOIm7uniqJ_3AgD9QQJlTrCUJTQ)]
* Underlying Tech: It uses an extended version of infini-gram with a parallel algorithm that reduces lookup complexity to \(O(L \log N)\). [[1](https://www.google.com/goto?url=CAESWgHrOzAVoVYHLgJxMVIjxyaZx7wDArKB6jxCb1tOprJFofLF9_o_Lr6foJNzJ2skLWhN04W7o7uFmFuQkrV4xPmu8JuLWWjcOIm7uniqJ_3AgD9QQJlTrCUJTQ)]

Supported Models

* OLMo 2 32B Instruct
* OLMo 2 13B Instruct
* OLMoE 1B 7B Instruct
* OLMo 3 family (including OLMo 3-Think 32B) [[1](https://www.google.com/goto?url=CAESWgHrOzAVoVYHLgJxMVIjxyaZx7wDArKB6jxCb1tOprJFofLF9_o_Lr6foJNzJ2skLWhN04W7o7uFmFuQkrV4xPmu8JuLWWjcOIm7uniqJ_3AgD9QQJlTrCUJTQ), [2](https://www.google.com/goto?url=CAESaQHrOzAVV_6J7u0vQR70ckMfNhiCogECpGpN15fGLDhAZkGzPPDHW94cWHDI3yvNEPPIeJCWECt_JJh8NwwM53Wiwyx94U6j_n8S84uLcd-yOdbxGgO2_8_63OmgYRHsjdzAlH-iXL3LIA)]

Key Use Cases

* Fact-Checking: Verify whether specific claims in a model's answer are backed by real training documents or generated from general parameters. [[1](https://www.google.com/goto?url=CAESWgHrOzAVoVYHLgJxMVIjxyaZx7wDArKB6jxCb1tOprJFofLF9_o_Lr6foJNzJ2skLWhN04W7o7uFmFuQkrV4xPmu8JuLWWjcOIm7uniqJ_3AgD9QQJlTrCUJTQ), [2](https://www.google.com/goto?url=CAESkgEB6zswFSw37mmS0ky2JdwMbluTG9bXw6YrEyY7-RDR3C6gpGJF1AjuVzgdHaMhPrwWEs6-CqOPaBUaJmKtgKhm0K6DY4dgamujc7BlSKs3Q7zgBXwn4p50GiZOmvHB7LP_ros68_TLow3I8e5BC6voQvexCU7B9RANXq30erTczX0PJp4Eoot_gOSfIdL-s64rEQ)]
* Hallucination Diagnosis: Spot where a model mixes up facts or memorized text from source files. [[1](https://www.google.com/goto?url=CAESZQHrOzAVTuCtZhUvlAC1FgYlT-ioaSAfiV6VG-c9osiVQ_FPlF62I3S48qKZjg6PnH3vYzrPeKi7Rar1Z4mDks0EMNRTl8vcyc5d0cIMWkhvQoo_giR_HHzJhHcmcAGkUssJqLjF), [2](https://www.google.com/goto?url=CAESWgHrOzAVoVYHLgJxMVIjxyaZx7wDArKB6jxCb1tOprJFofLF9_o_Lr6foJNzJ2skLWhN04W7o7uFmFuQkrV4xPmu8JuLWWjcOIm7uniqJ_3AgD9QQJlTrCUJTQ)]
* Auditing & Transparency: Inspect the data recipes and pretraining paths for regulatory compliance or research. [[1](https://www.google.com/goto?url=CAESfgHrOzAVd9pZK6hXPDhajqcIyrIpeoeKsOtolrBXNH59t2FmwwJ6HuF-YnkP1-EVgZEWX4T7kBh1XIkmkww2H4xJ8oprHeZCLafy4gXrndLDeynguHxNr21pz4Ein_w-Tws5-F6y0jfcbHLurOUXxmovED45PgVVy2GZwu4b7w), [2](https://www.google.com/goto?url=CAESaQHrOzAVV_6J7u0vQR70ckMfNhiCogECpGpN15fGLDhAZkGzPPDHW94cWHDI3yvNEPPIeJCWECt_JJh8NwwM53Wiwyx94U6j_n8S84uLcd-yOdbxGgO2_8_63OmgYRHsjdzAlH-iXL3LIA)]

Would you like to know how to access the open-source code for OLMoTrace on GitHub/Hugging Face, or are you looking for details on a specific OLMo model version?
Allen Institute for Artificial Intelligence
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X
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