Buy-side origination tooling
- Problem
- Weeks of research and drafting on every mandate.
- Built
- Market map, screening, sourced research and draft approach letters in one app. Partners review and sign.
- Result
- Research time cut to a fraction. Judgement unchanged, by design.
Python · Claude API · model per task · cited sources · cost logging · tests
How it works
The flow
- Map the market
- Screen on the numbers
- Team picks targets
- Research each target
- Draft the letter
- Check every fact
- Partner edits and signs
SoftwareA person decides
Design choices
- Engines before screens. Each tool was proven from the command line before it got a page, and the page calls that tested engine, so the screen cannot drift from what was tested.
- The right model for each job. Haiku reads websites and filings, Sonnet writes the analysis, Opus writes the letter, all set from one list.
- Source everything. Every claim carries its source and a confidence level. A checker traces every name and number in a letter back to the research before a partner sees it.
- Refuse rather than bluff. Paid services are checked before a run, and a run that cannot succeed will not start. Every call is costed and logged.
How I tested it
- 23 offline checks, each proved by breaking the code on purpose: 150+ deliberate breaks, every one caught.
- A root-cause review of three months of runs: 31 findings, 29 fixed.
- Success reported weekly against a 99% target, where a wrong letter counts as a failure.
- About 49,000 lines of Python, about 8,000 of them tests. Sole builder, working with Claude Code.
Version one
A nine-stage pipeline for a UK search fund, with three human review gates. It took 200 companies through ownership checks, scoring, sourced research and drafted messages in 10 to 12 hours for about £80, against roughly 300 a week by three people by hand. About 61,000 lines of Python, with about 1,360 tests.