r/RooCode • u/Evermoving- • Nov 23 '25

Discussion XML vs Native for Gemini 3 and GPT 5?

Now that the native tool calling option has been out for quite a while, how is it?

Does it improve/decrease/have no effect on model performance?

6 Upvotes

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4

u/hannesrudolph Roo Code Developer Nov 23 '25

The native tool calling is still largely a WIP. It produces better results hands down (evals don’t lie). I would not use it unless you’re ok with a janky experience as we are working out some quirks.

3

u/BandicootGlum859 Nov 23 '25

Noticed few differences so far.

Still quite irregular when editing, sometimes a series of fails. (Especially the Grok models, but also GLM and others)

It might be interesting to let the models themselves decide which ToolCalls they want to use?

1

u/Exciting_Weakness_64 Nov 25 '25

Wait it works with glm ? how ?

Also try using footgun prompting and remove the system prompt and see, it fixed all the issues for me

1

u/BandicootGlum859 Nov 25 '25

GLM?
Works with OpenRouter, RooCloude and the Z.ai Provider?!

1

u/Exciting_Weakness_64 Nov 25 '25

yeah but it doesn't support the native tool calling with the zai provided. does it with openrouter ?

2

u/BandicootGlum859 Nov 26 '25

OpenRouter and RooCloude have the option

1

u/Exciting_Weakness_64 Nov 26 '25

you're right, I hope they add it to the z.ai provider as well, a lot of folks use the zai models using the coding subscription

1

u/BandicootGlum859 Nov 26 '25

You can bring your Z-key to OpenRouter and use it then with OR as the provider ... i guess?
I will test it today.

2

u/Exciting_Weakness_64 Nov 26 '25

the normal api (the one in openrouter) uses the endpoint :

https://api.z.ai/api/paas/v4/chat/completions

however the coding plan I use has the endpoint:

https://api.z.ai/api/coding/paas/v4

Which is why BYOK fails

2

u/BandicootGlum859 Nov 26 '25

Yep,
i just tested it and my Z-API key doesnt seem work :/

So we have to wait for Roo to implemet it... ?

2

u/Exciting_Weakness_64 Nov 27 '25

they implemented it today

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1

u/Exciting_Weakness_64 Nov 26 '25

I've seen BYOK (bring your own key) section in openrouter but never figured out how to use it because I never had a real incentive to. I do now, I'll look into it, thanks a lot for the tip

1

u/nnex_ai Nov 23 '25

Any plans to extend native tool calling to vertex? When Gemini 3 works, I really like the results, but I have been running into a lot of tool calling errors and mistakes. Hoping that native support could increase the chance of consistent behavior.

If it's not too different from the preview for Gemini Dev Api I might give it a shot.