Foundry vocabulary

crucible/state names its lifecycle after a foundry: you Forge a definition, Quench it solid, Cast instances, and Fire events at them. The metaphor is load-bearing: each verb marks a real boundary between mutable authoring, an immutable definition, and a running instance.

Lifecycle verbs

Verb	Signature (shape)	What it does	When to call it
Forge	Forge[S,E,C]("name") *Builder	Opens a mutable builder. Declare states, transitions, and register named behavior (.Guard, .Action, .Reducer, .Service, .Actor).	Once, at the start of defining a machine.
Temper	b.Temper() []Diagnostic	Optional, non-failing lint/diagnostics pass over the builder. Returns findings; never panics, never freezes.	Before Quench, when you want to surface reachability or wiring warnings.
Quench	b.Quench() *Machine	Freezes the builder into an immutable *Machine. Panics on misconfiguration (unknown states, dangling refs).	Once, when the definition is complete. The *Machine is safe to share across goroutines.
Cast	m.Cast(entity, opts...) *Instance	Creates a running *Instance seeded with your context entity (by value).	Per entity you want to track. Cheap; cast freely.
Fire	inst.Fire(ctx, event, opts...) FireResult	Advances the instance. Returns FireResult{NewState, Effects, Trace, Err}. Performs no IO; effects are data.	Every time an event arrives.
Assay	m.Assay(state, entity, opts...) error	Verifies that an externally-built entity is legally in a given state, running the relevant guards. FailFast by default; Aggregate() collects all violations.	When an entity is reconstructed from storage or another system and you need to trust its state.

Plain verbs

Not everything earns a metaphor. These read literally:

Verb	Signature (shape)	What it does
PlanPath	m.PlanPath(from, to, entity, opts...) ([]E, error)	Computes a sequence of events that would drive an entity from one state to another.
Trace	(field on FireResult)	The ordered record of what happened during a Fire: transitions, guards, regions.
ToJSON / LoadFromJSON	m.ToJSON() / LoadFromJSON[S,E,C](b)	Round-trip the canonical IR losslessly to and from JSON.
ToMermaid / ToDOT	m.ToMermaid() / m.ToDOT()	Render the machine as a diagram for docs or inspection.

A typical session uses Forge → (Temper) → Quench once, then Cast and Fire many times, with Assay at the edges where entities cross trust boundaries.