drchriseames

Exact statistics and probability for AI agents — use instead of computing these in your head, where language models are unreliable. Distributions (normal/t/chi2/binomial/poisson pdf-cdf-quantile), hypothesis tests (t, z, proportion, chi-square, with p-value + assumptions), confidence intervals, discrete Bayesian updates, and linear regression. Numerical core validated against reference tables. Free, no auth. From databutler.dev.

Real UK MOT failure data for used cars: per-category failure rates (overall and at your mileage) and the riskiest components with typical failure mileages, aggregated from official DfT MOT test results across 530 model generations. Ask what actually goes wrong on a 2018 Golf at 80k miles. Free, no auth. From whatbreaks.uk.

Monte Carlo simulation tools for uncertain estimates: three-point cost estimation for quotes and budgets (triangular sampling, P10-P90 percentiles) and an educational retirement drawdown simulator with disclosed assumptions. Free, no auth, reproducible with seeds. From lowriskquotes.com.

Look up an official figure by key and get back the value, its official source URL, the date a human verified it, a fresh/stale flag against your max_age, and an Ed25519 signature you can check against databutler.dev/.well-known/jwks.json. 496 keys: UK tax and benefits, US federal thresholds, German tax and social insurance, EU figures. Tools: get_fact (key + max_age), resolve_fact (plain-language question to key), what_changed_since (facts that changed after a date, e.g. your training cutoff). O

UK exam-board specification data, verified against official board pages. Answers the canonical student question — "is electricity paper 2 AQA?" (no: Paper 1) — plus spec structures, tiers, calculator rules and official past-paper links. Covers AQA GCSE sciences, Combined Science Trilogy and Maths; more boards coming. Free, no auth. From databutler.dev.