Open-source dev-tools
7 small tools, one constraint: they have to work in a room where you can't install anything and the data can't leave. Browser-only, BYOK, no backend — not a stylistic choice, just what's left when the environment isn't yours.
Six of them make the Claude API legible — observe a single call, replay an agent trace, compare prompts side by side, build a tool-use loop interactively, pre-flight a prompt before you send it, stress a structured-output contract until it breaks. The seventh does the same for a page's performance budget: simulate what removing a script would actually cost, before you spend a sprint finding out.
Read the writing
Each tool has one or two long-form posts explaining the engineering decision behind it — the protocol-level details, the failure modes it surfaces, and what it changes about how you ship.