what i learned building agent skills that admit what they can't check

agent skills moved to a neutral foundation this week, which felt like a good moment to write up the set i've been building

HousingWizard is a free MIT set of agent skills that put an AI assistant on the home buyer's side. it covers due diligence notes, money limits, offers, inspection requests, contract review, closing, renovation, and a floor plan to quantities to quote package flow. install:

npx skills add daniel1001a/HousingWizard

the rules i held it to

home buying is a place where a confident wrong answer costs real money, so i wrote the rules before the features

1. every output ends with a "This tool cannot check" section. it lists what a person still has to verify
2. it never makes up a number. the default price book is empty, so nothing gets priced without a sourced quote
3. floor plan quantities stay UNCONFIRMED until you confirm the overlay, and --require-confirmed refuses to write anything that isn't
4. every quantity in the takeoff carries a rule ID and JSON pointers back to where it came from
5. the per trade quote packages (scope.md, quantities.csv, assumptions.md) have no prices in them, so contractor quotes are comparable
6. NYC permit answers include a citation, URL, and the date it was read
7. plain Python 3, no dependencies, and the scripts send nothing anywhere

what i learned

writing the "cannot check" section was harder than writing the features. you have to actually know where your tool stops

an empty default is a feature. it felt weird to ship a price book with nothing in it, but it's the only way i could promise no invented prices

plain files beat a service here. people can read exactly what the agent is told before they install it

honest limits

it's early. it has been tested on fixtures, not real floor plans. permit rules are NYC only. it isn't legal, financial, or inspection advice

repo: https://github.com/daniel1001a/HousingWizard

if you build skills too, i'd love to hear how you handle the "what can't this check" part