# Langsmith Playground: No generation chunks were returned

**URL:** <https://forum.langchain.com/t/langsmith-playground-no-generation-chunks-were-returned/2195>\
**Category:** LangSmith Product Help\
**Created:** [November 13, 2025, 12:10pm UTC](https://forum.langchain.com/t/langsmith-playground-no-generation-chunks-were-returned/2195 "2025-11-13T12:10:54Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![betazeng](https://avatars.discourse-cdn.com/v4/letter/b/258eb7/32.png) [@betazeng](https://forum.langchain.com/u/betazeng)\
**Post date:** [November 13, 2025, 12:10pm UTC](https://forum.langchain.com/t/langsmith-playground-no-generation-chunks-were-returned/2195/1 "2025-11-13T12:10:54Z")

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I am using langsmith playground to debug my prompt. I use OpenAI compatiable Endpoint, and set my apikey in browser. When I start running, I got error as below:

**ValueError(‘No generation chunks were returned’)Traceback (most recent call last):  
File “/usr/lib/python3.11/site-packages/langchain\_core/runnables/base.py”, line 2383, in \_atransform\_stream\_with\_config  
File “/usr/lib/python3.11/site-packages/langchain\_core/runnables/base.py”, line 3443, in \_atransform  
File “/usr/lib/python3.11/site-packages/langchain\_core/runnables/base.py”, line 5718, in atransform  
File “/usr/lib/python3.11/site-packages/langchain\_core/runnables/base.py”, line 1578, in atransform  
File “/usr/lib/python3.11/site-packages/langchain\_core/language\_models/chat\_models.py”, line 709, in astream  
ValueError: No generation chunks were returned**

PS:

1. My base\_url belongs to the company’s intranet.

2. My api\_key is definitely correct, because it works perfectly fine for me using the ChatOpenAI() SDK.

3. I deploy a local server used “langraph dev“, get a studio to use langsmith playground

4. this is my config:

What could be causing the request to fail?