extension-api/
├── SKILL.md                        # This file
├── scripts/
│   ├── extension_base.py           # ExtensionBase ABC, canonical commands
│   ├── extension_discovery.py      # Extension discovery, loading, aggregation
│   ├── build_discover.py           # Module discovery, path building
│   ├── build_result.py             # Log file creation, result construction
│   └── build_parse.py              # Issue structures, warning filtering
└── standards/
    ├── extension-contract.md       # Extension API contract
    ├── canonical-commands.md       # Command vocabulary and resolution
    ├── config-callback.md          # Project configuration callback
    ├── build-base-libs.md          # Base library API reference (optional)
    ├── build-execution.md          # Execution patterns (optional)
    ├── build-return.md             # Return value structure (optional)
    ├── build-project-structure.md  # Module discovery output (optional)
    └── architecture-overview.md    # System architecture (optional)

# Apply config_defaults() callback for all extensions
python3 .plan/execute-script.py plan-marshall:extension-api:extension_discovery apply-config-defaults

status	success
extensions_called	3
extensions_skipped	2
errors_count	0

import sys
from pathlib import Path

# Add extension-api scripts to path
extension_api_path = Path(__file__).parent.parent.parent / "extension-api" / "scripts"
sys.path.insert(0, str(extension_api_path))

from extension_discovery import (
    discover_all_extensions,
    discover_project_modules,
    get_build_systems_from_extensions,
    get_skill_domains_from_extensions,
    apply_config_defaults,
)

from build_discover import (
    discover_descriptors,
    build_module_base,
    find_readme,
)

from build_result import (
    create_log_file,
    success_result,
    error_result,
)

from build_parse import (
    Issue,
    filter_warnings,
    partition_issues,
)

from extension_base import (
    CMD_CLEAN,             # "clean"
    CMD_COMPILE,           # "compile"
    CMD_TEST_COMPILE,      # "test-compile"
    CMD_MODULE_TESTS,      # "module-tests"
    CMD_INTEGRATION_TESTS, # "integration-tests"
    CMD_COVERAGE,          # "coverage"
    CMD_BENCHMARK,         # "benchmark"
    CMD_QUALITY_GATE,      # "quality-gate"
    CMD_VERIFY,            # "verify"
    CMD_INSTALL,           # "install"
    CMD_CLEAN_INSTALL,     # "clean-install"
    CMD_PACKAGE,           # "package"
    ALL_CANONICAL_COMMANDS,
    PROFILE_PATTERNS,      # Profile ID to canonical mapping (for internal use)
)

#!/usr/bin/env python3
"""Extension API for {bundle-name} bundle."""

from pathlib import Path
from extension_base import ExtensionBase


class Extension(ExtensionBase):
    """Extension for {bundle-name} bundle."""

    def get_skill_domains(self) -> dict:
        """Domain metadata for skill loading."""
        return {
            "domain": {
                "key": "domain-key",
                "name": "Domain Name",
                "description": "Domain description"
            },
            "profiles": {
                "core": {"defaults": [], "optionals": []},
                "implementation": {"defaults": [], "optionals": []},
                "testing": {"defaults": [], "optionals": []},
                "quality": {"defaults": [], "optionals": []}
            }
        }

    def discover_modules(self, project_root: str) -> list:
        """Discover modules in the project.

        Returns list of module dicts with:
        - name, build_systems, paths, metadata, packages, dependencies, stats, commands
        """
        # Find descriptors
        from build_discover import discover_descriptors, build_module_base
        descriptors = discover_descriptors(project_root, "descriptor-file")

        modules = []
        for desc_path in descriptors:
            base = build_module_base(project_root, desc_path)
            # Enrich with extension-specific metadata, stats, commands
            modules.append({
                "name": base.name,
                "build_systems": ["my-build-system"],
                "paths": base.paths.to_dict(),
                "metadata": {},
                "packages": {},
                "dependencies": [],
                "stats": {"source_files": 0, "test_files": 0},
                "commands": self._resolve_commands(base)
            })
        return modules