The seven Agent primitives

Learn the complete compositional language for Agent judgment, durable history, time, delegation, and volume.

Constal’s Agent language has exactly seven primitives, in this canonical order: turn, ledger, commit, await, spawn, map, and reduce. The first five let an Agent exercise judgment across history, time, and delegated work. The final two let the same program operate over data larger than one invocation.

The language

Primitive	Meaning
`turn`	Exercise judgment through a pinned Model, optionally offering governed Tools
`ledger`	Read, page, branch, or truncate durable history
`commit`	Establish a durable fact, result, checkpoint, delivery, or compensation point
`await`	Suspend until authenticated external input or a declared deadline arrives
`spawn`	Delegate bounded work to a registered, independently durable subtask
`map`	Apply registered work across partitioned, content-addressed data
`reduce`	Deterministically combine partitioned results, globally or by key

These words are deliberately orthogonal. turn decides; ledger remembers; commit makes truth durable; await crosses human or external time; spawn introduces bounded independent work; map distributes volume; and reduce brings that volume back together.

Contracts

ctx.turn(spec)
ctx.ledger.view(name, options)
ctx.ledger.page(cursor)
ctx.ledger.branch(fact)
ctx.ledger.truncate(fact)
ctx.commit(value, options)
ctx.await(label, options)
ctx.spawn(task, input, options)
ctx.map(partitionFn, input, options)
ctx.reduce(foldFn, input, options)

Several operations return durable Handles. A Handle has one stable identity and one terminal outcome; derived joins such as all, select, and race compose Handles without adding runtime primitives.

What is not an eighth primitive

ctx.invoke() and ctx.invokeAsync() cross the governed Resource boundary. ctx.step() records a replay-safe local memoization boundary. Tools expose selected Resource capabilities to a Model. Policy grants or denies authority. Channels translate communication. Credentials supply secret material only to authorized integrations. These are essential runtime boundaries and supporting mechanisms, but none adds another word to the Agent language.

ReAct, planners, supervisors, retries, approvals, transcripts, memory-backed behavior, and final-answer conventions are compositions. See From primitives to production for the patterns.