Claude filled the organizer and found a depreciation
Alex Willen had Claude Code fill a tax organizer, with Claude in Chrome typing into the CPA's site. Claude found a goodwill depreciation the CPA confirmed.
Done with Claude CodeAdvanced
This is a public report, not advice from Skatteetaten, NAV, Altinn or an accountant. Check figures, deadlines and decisions against the original.
What was done
On 05 March 2026 Alex Willen writes in The Automated Operator that his CPA sends an organizer embedded in a website, with no downloadable PDF. He had Claude in Chrome walk the form and make JSON of the fields, gave that to Claude Code to fill in, and had Claude in Chrome type it back. The first pass took something like 15-20 minutes and cut off partway through page 7. He did two pages at a time. He hit a usage limit at page 12. After the limit reset, Claude in Chrome finished. He gave it three pages at a time. After his own review he writes that it nailed everything. It was missing items including his daughter's SSN. He then asked Claude to review the 2024 return against the source documents. The first answer said everything looked fine, then admitted the documents had not been compared. In plan mode it worked for ten minutes and said the CPA had missed a depreciation. Willen buys brands and can deduct 1/15 of the purchase price each year. The CPA replied yes, and that they will start depreciating the goodwill from 2025. Later the CPA said he would amend the filing. Willen also asked for advice on a SEP-IRA. Claude first said up to 25% of the income from each single-member LLC. ChatGPT said the math was closer to 20%. Claude agreed. Claude then filled in brokerage forms. Willen printed the signature pages, signed them and scanned them. A later attempt to recreate the whole 2024 return was contaminated: Claude Code still had the numbers in a markdown file and in CLAUDE.md after he deleted the return itself. An isolated folder with memory off finished in about an hour. The fetched text stops before he writes how that run compared.
How it went
The organizer matched what he checked on the site. The CPA confirmed the depreciation and later said he would amend the filing. The comparison of the isolated 2024 run is not in the text that was fetched.
Worth knowing
Check the original. The page is cut off before the last comparison. The depreciation is not stated in currency. 25% was corrected to closer to 20%. Claude in Chrome would not take JSON as a file, only images, so he pasted the text.
How to do it
- Have the browser agent list the fields in [form] as JSON.
- Have the coding agent fill only what it finds in [document-folder], and say what is missing.
- Read every field on the site yourself before anything is filed.
Try it with Claude Code
Read the fields in [form] and fill only what you find in [document-folder]. List what is missing. Do not type into the CPA site, do not file, and do not pay until I say yes.
Replace text in brackets with your own.
Done when. The fields have been read against the documents, and nothing has been filed or paid unless you said yes.
Safety rule. The agent does not file the return and does not pay. You read the figures and you sign.
Read the original
Read the original · The Automated Operator ·