Writing

Technical notes on actuarial modelling. Written to stay useful, not to stay current.

• Build vs buy after the cost collapse

  The cost of building a production-grade actuarial engine has collapsed. The cost of trusting one has not. What that asymmetry means for insurers weighing bespoke models against commercial suites.

  modelling strategy · validation · build vs buy

• Building an engine with an agent crew

  How one person directs software-writing agents to production-grade output: specifications, review gates, regression fingerprints, and the unglamorous discipline in between.

  engineering practice · agents · validation

• The whole rulebook, at the speed of a question

  A worked pattern for asking questions of long regulatory texts: retrieval over public rules, the failure modes that matter, and the checks that catch them.

  regulation · retrieval · engineering practice

• Reviewing a model with an agent: a working method

  A repeatable method for independent model review with machine assistance: what to hand the machine, what to keep for yourself, and where the traps are.

  model review · validation · agents

• Why I build in the open

  Twenty years of building models insurers could not open; the tools that finally made the alternative buildable by one person; and why the engines are free.

  open source · modelling strategy · motive