Workflow vs agent
A workflow is a fixed path; an agent chooses its path. Start with workflows and only graduate to agency where the branching is real. Most “agent” problems are workflow problems wearing a costume.
Tool design
Tools are the agent’s hands. Name them clearly, scope them tightly, and return structured results. A great tool surface beats a clever prompt every time.
Context engineering
Give the model exactly what it needs and nothing it doesn’t. Retrieval, not a dump. The skill is curation under a token budget.
Evaluation harnesses
If you can’t measure it, you can’t trust it in production. Build the eval before you build the agent; let red cases drive the design.