Best Open Source LLM for Langraph Agent

Posted by geekyrahulvk@reddit | LocalLLaMA | View on Reddit | 8 comments

Hi Community,

I am looking for an open source LLM preferably under 30B to power my agent. My agent workflow includes around 4-5 tool calls. I have tested multiple models but so far only found Qwen3 14b to be acceptable. Most other models hallucinate after the first or second tool call.

I wanted to get the community’s opinion on whether there was any another model i can try out ?

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Bohdanowicz@reddit

I use qwen3 vl 30b a3b instuct with no issues. Also non vl instruct.

120tps for vl, higher for non vl.

I find the qwen models react well to cot prompts with instruct.

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lly0571@reddit

GPT-OSS-20B might be slightly better than Qwen3-30B-A3B-2507 for tool calls, but worse for world knowledge. Maybe you can try that model.

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geekyrahulvk@reddit (OP)

I was reading through the OpenAI cookbook and noticed that OpenAI recommends a specific tool format for the oss models which seems to be different from the default used while defining tools in lang chain and langraph.

Is that something to be taken into consideration ?

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lly0571@reddit

GPT-OSS deployed with vLLM works with langchain.agent or regualar OpenAI chat completion API for Function Calling. I think vLLM handles the Harmony chat format.

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geekyrahulvk@reddit (OP)

Tried gpt-oss 20b and it is working perfectly for my use case. Thank you

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Ilivemkrr@reddit

If only for tool calling you can tries xlam series or some fine tuning tool calling model: https://huggingface.co/collections/beyoru/agent-rc

https://huggingface.co/collections/Salesforce/xlam-models

https://huggingface.co/Team-ACE/ToolACE-8B

My current company take small model below 10B for agent tasks and it still pretty good until now

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geekyrahulvk@reddit (OP)

Thank you for this suggestion. I will try this out

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geekyrahulvk@reddit (OP)

Thanks everyone.

I tried the gpt-oss 20b and it is perfect for my use case. I am satisfied with it’s tool calling ability as well as it able to call around 4-5 tools without any issues in my workflow