Glossary
Defined terms before they become assumptions.
This page is the vocabulary floor for the learner path. If a path stage assumes a term, it must have already been introduced or be defined here.
- Specification
A statement of what a system, product, or workflow is meant to be or do. It may include prose, diagrams, code, policies, examples, and checkable contract structure.
foundation
- Authoritative sources
The prose requirements, diagrams, source code, policies, and standards that own the truth. Varro should reflect these sources, not replace them.
foundation
- Source of truth
The artifact that wins when two surfaces disagree. In this course, source artifacts outrank Varro pages, agent answers, and caller preferences.
foundation
- Checkable contract
A specification structure that a tool can validate and reject. The point is not more prose; the point is a contract that can fail when it is wrong.
Varro
- Varro
The governed specification layer that turns source-backed system structure into a checkable VSL contract.
Varro
- VSL
Varro Specification Language: the language used to describe systems, types, fields, enums, actions, workflows, routes, context, and runtime settings.
Varro
- System
The top-level VSL container for a governed domain. It names the mission, authority, maturity, context, type model, behavior, and surfaces.
VSL construct
- Type
A named record shape made of typed fields. In VSL, types describe data shape and do not own behavior.
VSL construct
- Field
A named value inside a type, with a kind and a required or optional presence rule.
VSL construct
- Enum
A closed set of allowed values. New values are not silently accepted at use sites.
VSL construct
- Action
A governed operation that can change state. It carries inputs, risk, and lowering information, and is run under preview-by-default.
VSL construct
- Query
A read contract that declares what information can be asked for and which authority it reads from. A query does not mutate state.
VSL construct
- Workflow
An ordered sequence of governed steps. The order is part of the contract.
VSL construct
- Route
A named address in the governed Helios resource space. It is not just an HTTP endpoint label.
surface
- View
A declared way to render or project a selected part of system state.
surface
- Context
The governed resource root that anchors how routes, views, and runtime surfaces are resolved.
surface
- Runtime
The configured execution environment and settings that govern how a checked contract is hosted and operated.
surface
- Compile
The VSL lowering step that produces a typed downstream artifact for a named target.
surface
- Helios
The build and run engine that ingests the checked contract, generates operational surfaces, and hosts governed runtime services.
build/run layer
- Live system
The running governed system after a checked contract has been built, deployed, and connected to services and data.
runtime
- Agent surface
A product, API, tutor, dashboard, CLI, or AI-agent interface that consumes the governed system without becoming the source of truth.
runtime
- Authority stack
The ordering rule for disagreements: authoritative sources first, Varro as the window, callers and agents last.
governance
- Preview-by-default
The safety principle that governed actions describe their effects before committing them. Execution is explicit rather than accidental.
governance
- Maturity
A rung in the specification lifecycle, such as draft, checked, bound, or hardened.
governance
- Crystallisation
The hardening path from loose intent to more formal and checked artifacts, described here with phases such as Plasma, Gas, Liquid, Solid, and Crystal.
governance
- Lean
A theorem-proving environment used in the broader hardening story. In this course it appears as part of the Crystal/proof end of the model, not as a prerequisite for starting Varro.
proof layer