THE LEDGER — Cost Basis & Trading Records OS Brain

$49.00
◆ cost_basis.py · the number your return needs

THE LEDGER — Cost Basis & Trading Records OS Brain

For the records you will need and do not have. One orchestrator plus ten specialists that compute cost basis across disposals, reconcile transactions across venues, and build the trail before a deadline rather than during one.

What makes it different

Most people reconstruct their trading year in the week the return is due, from exchange exports that no longer reconcile, for venues that have since closed. The basis script takes your transaction history and computes realised gains under FIFO, LIFO and weighted average, showing the difference between them — which is frequently large, and which may or may not be a choice you are allowed to make depending on where you live. Doing this in January rather than deadline week is the whole difference between a calculation and an archaeology project.

It ships working code, not just prompts cost_basis.py

Computes realised gains under FIFO, LIFO and weighted average from a transaction ledger, shows the difference each method produces, and flags every disposal with a missing or unmatched acquisition record. Every OS Brain in this drop carries its own executable component, so the judgement calls stay with you and the arithmetic stops being a matter of opinion. Runs anywhere Python runs, and the specialists still work on their own if you never open it.

Say it in plain words — it works out the rest

"Tax return is due"→ full pipeline, reconcile first
"Which method do I use?"→ 03 · often not your choice
"The exchange shut down"→ 05 · reconstruct from what remains
"I moved coins between wallets"→ 04 · transfers are not disposals
"I have no records at all"→ 02 · start from the chain and the bank

Inside · orchestrator + 10 specialists

01The Transaction SetEverything, every venue
02Reconstructing GapsWhen the export is gone
03Method SelectionFIFO, LIFO, average
04Transfers and DisposalsThe distinction that matters
05Venue FailureExchanges that no longer exist
06Fees and CostsWhat is deductible
07Realised and UnrealisedKeeping them apart
08The TrailEvidence that survives a question
09Ongoing CaptureSo next year is easy
10Records LedgerThe archive itself

Where it refuses to skip ahead

  • No calculation on an incomplete set — a basis computed from partial records is confidently wrong.
  • Transfers are not disposals — mislabelling them is the most common and most expensive error in the category.
  • Method is not a free choice everywhere — several jurisdictions mandate one, and picking the favourable one anyway creates a problem.
  • No number filed without professional review — this prepares the working. It does not file it and it does not sign it.
Works in all 7 channels
1Any chatupload the zip
2Claude Projectsadd as knowledge
3ChatGPT / GPTsknowledge files
4Gemini Gemsknowledge files
5Claude Codeskills folder
6Agent frameworkssystem instruction
7Paste-onlydegrades gracefully
The habit it is really selling: capture transactions monthly, so the annual job becomes twenty minutes instead of a weekend. Single-seat license. This is a record-keeping and calculation tool and explicitly not tax advice — cost basis rules, permitted methods and reporting obligations vary substantially by jurisdiction and change often. Have an accountant review the output before anything is filed.
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