Prompt engineering is becoming programming.

Why prompt engineering is turning into software engineering: the deterministic shell, the probabilistic core, and what can be declared at all.

Read this first if your team debates prompts in review meetings: it replaces that discussion with a boundary you can hold people to.

Six control-flow patterns from chaining to agents, and a map of twenty programming principles translated into prompt systems.

Use it to challenge any proposal that starts with the word agent, and to compare running cost between patterns before committing.

Declare the result instead of every step: typed structures between stages, contracts per module, and explicit permission boundaries.

This is the part that makes handover, vendor contracts and definition of done enforceable rather than negotiated.

A declared lifecycle for the model, transaction semantics for agent actions, eval-driven development and natural language as source code.

The operational core: how to bound cost, recover from partial failure, and know whether a change actually improved quality.

Distributed-systems problems, evaluator loops as feedback controllers, persistent state, and routing work to the cheapest reliable executor.

Read before approving a multi-agent architecture or a self-repairing loop, both of which look cheap and rarely are.

Human approval before irreversible actions, a fully declared prompt loop, and the destination: specification-driven probabilistic software engineering.

The governance and reporting layer: what to approve personally, and how to measure progress that survives the next model.