Prototype fast, ship safe

We’re in an upgrade cycle. New models, new specs, new primitives every quarter. In this environment, speed is table stakes — but speed without safety is just churn.

Here’s the pattern that worked repeatedly.

1) Prototype in days, not weeks

  • Use the smallest workable scope: a single path, a single data source, a single user action.
  • Build the “ugly vertical”: logging, toggles, metrics from day one so the prototype is demo‑able and measurable.
  • Keep the code disposable. You’re testing a behavior, not writing a framework.

Outcome: product can react to a real thing, not a deck.

2) Evaluate like a product

  • Define success criteria you can measure this week: CTR, dwell time, task completion, quality rubrics.
  • Run side‑by‑side with a baseline; capture deltas on real‑ish traffic.
  • Keep a curated eval set of 100–200 examples that reflect the problem slice.

Outcome: decisions are evidence‑based and legible to non‑engineers.

3) Add guardrails as soon as it’s interesting

  • Refusals for sensitive content; rate limits and timeouts; circuit breakers for dependencies.
  • Caching: product cache (repeat answers) + outage cache (stale‑acceptable answers).
  • Rollout plan with a crisp kill switch.

Outcome: you’re fast and trustworthy.

4) Productionize the parts that survive

  • Separate the prompt/policy layer from the application logic and UI style.
  • Turn one‑off scripts into versioned components with changelogs.
  • Invest in clear oncall docs: alerts, playbooks, owners.

Outcome: iteration gets faster over time instead of slower.

5) Culture: celebrate boring wins

Boring engineering is how you go fast on purpose. Launches that don’t wake anyone up at 3am are a competitive advantage.


A checklist I keep around

  • Scope is one flow, one persona
  • Metrics + logs from day one
  • Eval set + baseline comparison
  • Guardrails: refusals, limits, cache, kill switch
  • Rollout plan in the PR description
  • Ownership, runbook, and post‑launch bake time

The tech will change. The feedback loop is the product.