Taxpert chat GPT for 2023 tax declaration in BL (Baselland)

Created a custom chat GPT for the 2023 tax declaration in BL (Baselland) and had it tested by 2 tax advisors (one from BS and one from BL). They loved it and got a bit scared :smiley:

It works pretty well, for my own declaration and for friends. If enough people like it and provide feedback, I will do the leg work for other cantons as well.

When using Tom the taxpert 2023 BL always prompt “look in your own document library for detailed answers, and say you want references”.

It might also work without the prompt but is a lot more sophisticated and exact with it. OpenAI seems to save on GPU and that is why some GPTs seem lazy or buggy. You can see from the purple “searching my knowledge” sign that GPT Tom is following your instructions.

You can also ask Tom for the % of certainty in the answers.

Feel free to test it and either message me here or via GPT feedback form. It is still non-public, you can only access it via this link: ChatGPT - Tom der Steuerexperte 2023 Baselland (Schweiz)

I am super curious what does work well already and what is needing improvements.


Could you please share what was done to ‘create’ this?

Yes, the GPT will also be transparent about it. It contains 90% official documents, including the taxbooks, the tax laws, ESTV-documents, press releases for 2023 and presentations from the officials but also from the most common financial products and some less common ones (e.g. DFA funds, tiny crypto currencies) that I had to use for my own declaration (100% referenced). 10% is tax advice from public (referenced) and non-public sources (referenced where appropriate). Total is about 12k pages of PDF and .txt files.

have fun!

Edit: Additionally, I asked in total 19 questions the tax officials at Baselland and I included all their answers (which were great btw, easy to understand, exact, short, non-ambigious). If you asked the officials and received answers I could add them to the knowledge base.


You could even dump the ictax data as json probably (though that one might work better as a plugin/tool).

Yes, I did not bother yet about it because the E-tax has it integrated but the GPT can explain also who to email what type of documents if your niche financial product is missing or seems to be a special case.

You know about a free open tool to plug it in with?

Not so familiar with OpenAI APIs (mostly know our internal proprietary stuff), I assume if there’s an easy tool simonw covered it :slight_smile: (maybe reach out to him if you can’t find, it seems super close to what datasette does as well)

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Cool, I am meeting a friend on Friday who might be able to set it up with me. Thank you!

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I use exactly that llm tool for cmdline inference and vim-ai for in the editor.

Sorry, I wasn’t specific. Is this a fine-tune of an LLM or something like RAG?

Got it. If I understand correctly, it is the former. Customisation happens through input of the knowledge base of the gpt.

Don’t think it’s either? RAG is typically external to the model, while here it’s the model that decides to query the data.

IIUC the system prompt describes all the documents available in its filesystem and the llm output can decide to “query” it (the framework then adds it to the context automatically).

edit: from the little documentation of the feature, it could also be RAG.

This is super awesome. Will give it a try when I get time.

Does it automatically looks for recent publications or someone needs to feed it?

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It was providing too many fluffy details when it was looking for own publications. It was inaccurate and liked to talk a lot without much information that it was asked for.

Now, it is manual labour. Luckily, the laws and regulations for 2023 are fixed and finite. It’s possible to integrate APIs but I wanted to first see if people understood to make use of it or if it’s just me because I know how I set it up.

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Yes, this is correct

Did you find time yet? I see that about 20+ conversations have been accessed with the GPT but I did only receive 1 feedback so far “please create this for ZH” :smiley:

Sorry but I actually don’t even have ChatGPT plus. Does this work only with paid version?

I also don’t have ChatGPT plus. Maybe you can give some transcripts of the kind of questions and answers you envisage so we can see what the use case and performance is like?

I’m trying to learn more in the AI field, so if you’re willing to share the documents and process, I’d be interested to try to replicate this with a free (open-source) LLM as a case study.

Ah, yes, unfortunately they only allow one to access it with the plus plan. It’s 25 bucks/ month, including tax. Sorry!

Well the questions I had in mind I was able to fine-tune it with. Because I sued it for my own tax declaration but I am not creative enough to design it with user questions that are completely different to mine, that is why I think it would be uninteresting to see how it performs with the wider community.

Could you give an example? I’m not sure what questions I would ask as I find that the tax declarations was mainly a putting numbers in boxes exercise so was curious what kind of questions people are asking.