Pi is already the lean option — four core tools and minimal context overhead. Its remaining cost levers are model choice (switch mid-session to cheap models for routine stretches) and session hygiene via branching and compaction.
Pi's 30+ provider support with mid-session switching makes 'cheap for routine, frontier for hard' a live command instead of a config project.
Session branching lets you explore without dragging the full history forward; compaction keeps long-lived sessions from becoming token barges.
Pi's core is lean; extension sprawl is where hidden calls creep in. Know what each installed extension sends and when.
The provider-agnostic tactics (prompt caching, retry budgets, batch APIs) are in the general playbook.
Per request, usually — minimal tool definitions and lean context mean less fixed overhead. Total cost still tracks how you use it: model choice and session length dominate, same as anywhere.
A value model as default with mid-session escalation for hard moments — or a flat-rate endpoint in models.json if Pi is your daily driver, which removes the question entirely.
The structural version of all of this: run Pi on a flat monthly price with unlimited tokens, and the bill stops being a variable to manage. 2-minute Pi setup → · Best models for Pi →