Plan Marshall Plugin - Python Domain

Domain manifest skill providing Python development capabilities to plan-marshall workflows.

Enforcement

Execution mode: Extension manifest; modify only via Extension API contract.

Prohibited actions:

• Do not modify extension.py without updating this manifest documentation
• Do not bypass ExtensionBase inheritance for domain registration
• Do not hardcode skill paths; use bundle notation

Constraints:

• Extension must implement get_skill_domains() from ExtensionBase
• Axis-C edge derivation is opted into by multiple inheritance (Extension(ExtensionBase, DerivationResolverBase)); derive_edges() must stay a pure function of its arguments — no filesystem access, no subprocess
• Domain identity must match the bundle name convention (python)
• Profile-based skill organization must align with plugin.json registration

Purpose

Declares the Python domain configuration including:

• Domain identity (key: python)
• Profile-based skill organization (core, implementation, module_testing, quality)
• Module applicability detection based on Python build systems

Configuration

All configuration is in extension.py, which implements two axes of the Extension API.

Axis-A (ExtensionBase):

• get_skill_domains() - Domain metadata with profiles
• applies_to_module() - Check Python applicability via build systems and .py files
• provides_triage() - Returns pm-dev-python:ext-triage-python
• provides_arch_gate() - Returns the import-linter arch-gate tool binding (pm-dev-python:arch-gate-python)
• provides_file_globs() - Declares the Python source glob (['**/*.py']) seeded into skill_domains.python.file_globs for domain detection; contributes no build.map route

Axis-C (DerivationResolverBase, opted into by multiple inheritance):

• derivation_resolver_id() - Returns the stable provenance id python, stamped onto every edge this resolver produces
• derive_edges() - Pure join over the component_refs field module discovery materializes, selecting only import entries. The four markdown reference kinds belong to the sibling markdown resolver on pm-plugin-development. Unresolved targets, unknown endpoints, and self-edges are suppressed and reported as aggregated notes[] entries — one per category with a count and a bounded sample. The method performs no file I/O and runs no subprocess, and imports nothing from the bundle that materializes the field
• derivation_file_patterns() - Declares the file patterns this resolver derives from (['**/*.py']). Descriptive metadata rendered by the resolver-configuration menu, never a filter: activation is bound by resolver id in the machine-local derivation_resolvers section, not by matching a file

Detection

This domain is applicable when:

• python is listed in the module's build_systems
• .py files are found in source or test paths

Detection gates skill loading, not resolver registration. The Axis-C resolver is discovered unconditionally: discover_derivation_resolvers() iterates discover_all_extensions(), which returns every extension regardless of whether it applies to the current project, and applies no skill_domains filter. The applicability rules above therefore have no bearing on whether the python resolver runs — a project with no active Python domain still gets its edges. See ext-point-derivation-resolver.md § Discovery.

Build operations (pyprojectx execution, parsing, discovery) are provided by plan-marshall:build-pyproject, not this bundle.

Integration

This manifest is read by:

• skill-domains get-available - Lists available domains
• skill-domains configure - Applies domain configuration to marshal.json
• marshall-steward wizard - Domain selection during project setup