requires mashin

requires mashin

Declare the minimum Mashin language version required to compile and run this machine. If the runtime’s language version is lower than the declared requirement, compilation fails with a clear error rather than producing confusing parse or runtime failures from unsupported syntax.

This is a pre-machine directive: it appears before the machine keyword, at the top of the file (alongside written in if present).

When to use

Use requires mashin when your machine uses syntax or features introduced in a specific language version. This is especially important for:

• Machines published to the registry (krates) that will be consumed by users on different runtime versions
• Machines using recently added syntax (e.g., defines added in 0.28.0, has agency added in 0.25.0)
• Shared libraries or templates that need to communicate their minimum requirements

For machines used only within your own project, requires mashin is optional since you control the runtime version. For published krates, it is recommended.

Syntax

requires mashin ">=0.28.0"

The version string follows semver conventions. Supported operators:

Operator	Example	Meaning
>=	">=0.28.0"	This version or newer
>	">0.27.0"	Strictly newer than this version
~>	"~>0.28"	Compatible with 0.28.x (any patch version)
(bare)	"0.28.0"	Exactly this version

Examples

Basic version requirement

requires mashin ">=0.28.0"

machine data_transformer
  defines
    normalize(text) => text.trim().toLowerCase()

  accepts
    input as text, is required

  implements
    compute result
      {normalized: normalize(input.input)}

With locale directive

When both written in and requires mashin are present, either can come first. Both are pre-machine directives:

written in french
requires mashin ">=0.27.0"

machine classificateur
  accepte
    message en tant que texte, est requis

  implemente
    calcule resultat
      {traite: vrai}

Published krate with version requirement

requires mashin ">=0.25.0"

machine my_agent "My Agent"

has agency

achieves
  goal "Assist users with their tasks"

accepts
  request as text, is required

responds with
  response as text

implements
  ask handle, using: "anthropic:claude-sonnet-4-6"
    with task "Handle this request: ${input.request}"
    returns
      response as text

Implementation status

The requires mashin directive is parsed and compiled, but the runtime does not currently enforce version compatibility at execution time. Version checking happens at parse time: if the parser encounters requires mashin with a version higher than the current parser’s language version, it emits a compilation error.

Governance

requires mashin has no governance implications. It is a compile-time constraint, not a runtime behavior. No ledger events are produced.

Translations

Language	Keyword
English	requires mashin
Spanish	requiere mashin
French	requiert mashin
German	erfordert mashin
Japanese	mashin必須
Chinese	需要mashin
Korean	마신 필요

See also

• uses - Dependency declarations (machine-level, vs. this language-level)
• written in - Locale directive (also a pre-machine directive)