Building agentic AI, from first principles to the frontier.
Notes and guides on building software that plans, calls tools, verifies its own work, and ships to real users.
431 entries · 6 parts · 26 chapters · Updated 2026-08-21
The Agentic AI Field Guide
Everything else
Concepts
AI & agentic AI explained — plain-language entries for newcomers and intermediates.
Deep-Dives
Engineering fundamentals — architectures, memory, RAG, protocols, tools, reasoning, training, multi-agent.
Playbooks
Applied recipes for building agents in specific domains and roles.
Operations
How to run agents in production — evals, observability, cost, safety, governance.
AI Blog
Long-form posts, comparisons, and field notes from the agentic frontier.
From the blog
Stripe bought the meter, not the router
A payments company paid a reported $7 billion for the layer that counts AI usage, seven months after buying the layer that invoices it. Routing was never the scarce asset — the scarce asset is one normalised record of what every model call cost and who it was for, and if that record lives in your request path you are paying a percentage on every step your agents take.
Latest
- 2026-08-21Two AI Blog posts on Stripe buying the AI meter rather than the router and on which text-to-speech number actually decides a phone call, plus three pages on AI gateways, online experiments and collections agents
- 2026-08-20Two AI Blog posts on what a search API’s price unit really buys and on Gemini Spark moving into your own Chrome profile, plus three pages on ambient authority, eval-set maintenance and accounts-payable agents
- 2026-08-19Two AI Blog posts on the isolation technology under every agent sandbox and on why your eval metric picks your prompt optimizer, plus three pages on documentation agents, field-service dispatch and free-tier economics