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Domains

Domains are namespaces for concepts and pipes within a bundle. Every bundle declares exactly one domain in its header, and all concepts and pipes in that bundle belong to that domain.

What Domains Are For

Domains serve two purposes:

  1. Organization — group related concepts and pipes under a meaningful name. A domain like legal.contracts tells you what the bundle is about.
  2. Namespacing — prevent naming collisions. Two bundles in different domains can define concepts or pipes with the same name without conflict.

Declaring a Domain

The domain field in the bundle header sets the namespace:

domain = "legal.contracts"

Everything in this file — every concept and every pipe — belongs to legal.contracts.

Hierarchical Domains

Domains can be hierarchical, using . as the separator:

legal
legal.contracts
legal.contracts.shareholder

This allows natural organization of complex knowledge areas. A large package covering legal methods might structure its domains as a tree:

  • legal — general legal concepts and utilities
  • legal.contracts — contract-specific methods
  • legal.contracts.shareholder — shareholder agreement specifics

The hierarchy is purely organizational. There is no implicit scope or inheritance between parent and child domains. legal.contracts does not automatically have access to concepts defined in legal. If a bundle in legal.contracts needs a concept from legal, it uses an explicit domain-qualified reference — the same as any other cross-domain reference.

Domain Naming Rules

  • A domain code is one or more snake_case segments separated by ..
  • Each segment must match [a-z][a-z0-9_]*.
  • Recommended depth: 1–3 levels.
  • Recommended segment length: 1–4 words.

Reserved Domains

Three domain names are reserved and cannot be used as the first segment of any user-defined domain:

Domain Purpose
native Built-in concept types (Text, Image, Document, etc.).
mthds Reserved for the MTHDS standard.
pipelex Reserved for the reference implementation.

For example, native.custom and pipelex.utils are invalid domain names.

Same Domain Across Bundles

Within a single package, multiple bundles can share the same domain. When they do, their concepts and pipes merge into a single namespace:

my-package/
├── METHODS.toml
├── general_legal.mthds       # domain = "legal"
└── legal_utils.mthds         # domain = "legal"

Both files contribute concepts and pipes to the legal domain. If both files define a concept ContractClause, that is a conflict — an error at load time.

Domains Across Packages

Two packages can both declare domain = "recruitment". Their concepts and pipes are completely independent — there is no merging of namespaces across packages. The package boundary is the true isolation boundary.

This means recruitment.CandidateProfile from Package A and recruitment.CandidateProfile from Package B are different things. To use something from another package, you must qualify the reference with the package alias (see Namespace Resolution).

The domain name remains valuable for discovery: searching for "all packages in the recruitment domain" is a meaningful query. But discovery does not merge namespaces.

See Also