API documentation

Applies Sun Lab conventions for generating API documentation HTML pages from source code docstrings using Sphinx, autodoc, Napoleon, and optionally Breathe/Doxygen for C++ code.

Scope

Covers:

• •Sphinx configuration (conf.py) for Python-only, C++-only, and hybrid projects
• •RST file structure (index.rst, welcome.rst, api.rst)
• •Doxygen configuration and Breathe integration for C++ code
• •tox.ini [testenv:docs] build environment setup
• •Makefile and make.bat wrappers
• •Documentation hosting URL conventions
• •Documentation dependency management via ataraxis-automation

Does not cover:

• •MCP server modules or shared asset libraries — these are consumed by AI agents, not end-users, and MUST NOT be included in API documentation
• •Writing Python docstrings or type annotations (see /python-style)
• •README file conventions (see /readme-style)
• •pyproject.toml dependency sections (see /pyproject-style)
• •General project structure or architecture (see /explore-codebase)

Documentation architecture

Project archetypes

Sun Lab projects follow one of three documentation archetypes based on language composition:

Directory structure

For the full project-level directory tree, invoke /project-layout. The documentation-specific layout within each project is:

project-root/
├── docs/
│   ├── Makefile              # Unix Sphinx wrapper (delegates to tox)
│   ├── make.bat              # Windows Sphinx wrapper
│   └── source/
│       ├── conf.py           # Sphinx configuration
│       ├── index.rst         # Main page with toctree
│       ├── welcome.rst       # Landing page content
│       └── api.rst           # API reference directives
├── Doxyfile                  # (C++ and hybrid projects only)
└── tox.ini                   # Contains [testenv:docs] build environment

C++ and hybrid projects additionally generate:

docs/source/doxygen/
└── xml/                      # Doxygen-generated XML consumed by Breathe

Extension stack

Python-only projects use these extensions in this exact order:

extensions = [
    'sphinx.ext.autodoc',
    'sphinx.ext.napoleon',
    'sphinx_click',
    'sphinx_autodoc_typehints',
]

C++-only projects use:

extensions = [
    'breathe',
]

Hybrid projects use all Python extensions plus breathe, inserted after sphinx_autodoc_typehints:

extensions = [
    'sphinx.ext.autodoc',
    'sphinx.ext.napoleon',
    'sphinx_click',
    'sphinx_autodoc_typehints',
    'breathe',
]

Ordering constraint: sphinx_click MUST appear before sphinx_autodoc_typehints. sphinx_autodoc_typehints imports the sphinx.ext.autodoc.mock submodule at load time, which shadows the mock function that sphinx_click needs. Loading sphinx_click first ensures it captures the correct function binding before the submodule shadowing occurs.

Documentation dependencies

All documentation dependencies are bundled as runtime dependencies of ataraxis-automation. Downstream projects include ataraxis-automation in their dev optional dependencies, which transitively provides all documentation tools. You MUST NOT add Sphinx or documentation dependencies directly to downstream project pyproject.toml files.

Workflow

Creating documentation from scratch

1. •

   Determine archetype: Identify whether the project is Python-only, C++-only, or hybrid based on the source code language composition.

2. •

   Create directory structure: Create docs/source/ directory and the Makefile wrappers. Read rst-templates.md for Makefile and make.bat templates.

3. •

   Generate conf.py: Read conf-py-templates.md and use the appropriate archetype template. Replace all placeholder values with project-specific information.

4. •

   Generate RST files: Read rst-templates.md and create index.rst, welcome.rst, and api.rst using the templates. Populate api.rst with the correct directives for the project's modules.

5. •

   Configure Doxygen (C++ and hybrid only): Read doxygen-reference.md and create a Doxyfile at the project root listing all C++ source files.

6. •

   Configure tox build: Add the [testenv:docs] section to tox.ini following the appropriate pattern for the archetype.

7. •

   Verify: Run through the verification checklist below.

Modifying existing documentation

1. •

   Read existing files: Read docs/source/conf.py, docs/source/api.rst, and any other files you intend to modify before making changes.

2. •

   Identify archetype: Check the extensions list in conf.py to determine the project archetype.

3. •

   Apply changes: Follow the conventions in this skill and the reference files. Common modifications include:

   • •Adding new Python modules to api.rst via automodule directives
   • •Adding new Click CLI groups to api.rst via click directives
   • •Adding new C++ source files to api.rst via doxygenfile directives (and to Doxyfile)
   • •Updating project metadata in conf.py and welcome.rst
4. •

   Verify: Run through the verification checklist below.

Key conventions

conf.py rules

• •Version extraction MUST use importlib_metadata.version() for Python and hybrid projects. C++-only projects hardcode the version string.
• •Copyright format: 'YEAR, Sun (NeuroAI) lab' where YEAR is the current year.
• •The templates_path and exclude_patterns fields are included but left at defaults (['_templates'] and [] respectively).
• •Napoleon is configured for Google-style docstrings only (napoleon_numpy_docstring = False).
• •All Napoleon and sphinx_autodoc_typehints settings MUST match the templates exactly. See conf-py-templates.md for the full settings.
• •The HTML theme is always furo. Furo provides built-in light/dark mode toggling with no additional extensions required.

api.rst rules

• •Each documented module or file gets its own RST section with an =-underlined heading.
• •Python modules use automodule with :members:, :undoc-members:, and :show-inheritance:.
• •Click CLI groups use click with :prog: set to the CLI entry point name and :nested: full.
• •C++ files use doxygenfile with :project: set to the project name.
• •Section headings MUST be descriptive names, not module paths (e.g., "Precision Timer" not "ataraxis_time.precision_timer.timer_class").
• •You MUST NOT add automodule directives for MCP server modules or shared asset modules. These components are designed for consumption by AI agents, not end-users, and do not belong in API documentation.

welcome.rst rules

• •Title format: Welcome to PROJECT_NAME API documentation page with matching = underline.
• •First paragraph: the bare project description — the same sentence used in all other canonical description locations for the project archetype (e.g., pyproject.toml, __init__.py, README.md, or library.json). No language or project name prefix.
• •Second paragraph: standard Ataraxis project attribution with Sun (NeuroAI) lab link.
• •Third paragraph: standard disclaimer that the site contains API docs only, with link to GitHub repository.
• •Footer: explicit RST link targets for the GitHub repo and Sun lab URLs.

tox.ini docs environment

For the complete tox.ini conventions and all other environment definitions, invoke /tox-config. /tox-config is the authoritative source; if any pattern here conflicts, /tox-config takes precedence. The docs-specific patterns are summarized here for convenience.

Python-only projects (no external Doxygen dependency):

[testenv:docs]
description =
    Builds the API documentation from source code docstrings using Sphinx. The result can be
    viewed by loading 'docs/build/html/index.html'.
depends = uninstall
commands =
    sphinx-build -b html -d docs/build/doctrees docs/source docs/build/html -j auto -v

C++ and hybrid projects add Doxygen before Sphinx:

[testenv:docs]
description =
    Builds the API documentation from source code docstrings using Doxygen, Breathe and Sphinx.
    The result can be viewed by loading 'docs/build/html/index.html'.
deps = ataraxis-automation==VERSION
depends = uninstall
allowlist_externals = doxygen
commands =
    doxygen Doxyfile
    sphinx-build -b html -d docs/build/doctrees docs/source docs/build/html -j auto -v

Rules:

• •The depends = uninstall ensures a clean environment state before building.
• •Downstream projects pin deps = ataraxis-automation==VERSION to the current release. The ataraxis-automation project itself omits this field since it IS ataraxis-automation.
• •The Sphinx build command MUST use -j auto for parallel building and -v for verbose output.
• •C++ and hybrid projects MUST add allowlist_externals = doxygen and run doxygen Doxyfile before the Sphinx build command.
• •C++-only projects use skip_install = true since there is no Python package to install. See doxygen-reference.md for the full tox pattern.

Hosting convention

Documentation is hosted on Netlify with standardized URLs:

https://PROJECT_NAME-api-docs.netlify.app/

This URL is declared in pyproject.toml under [project.urls] as the Documentation key.

Makefile and make.bat

These are standard Sphinx wrapper files. They are rarely used directly since builds are invoked via tox (tox -e docs). Use the exact templates from rst-templates.md when creating new projects.

Related skills

Proactive behavior

You should proactively offer to invoke this skill when:

• •Creating a new Sun Lab project that needs API documentation
• •Adding new Python modules or Click CLI commands that should appear in API docs
• •Adding C++ source files to a hybrid or C++ project
• •The user asks about Sphinx, autodoc, Breathe, Doxygen, or documentation generation

Verification checklist

You MUST verify your work against this checklist before submitting any documentation changes.

API Documentation Compliance:
- [ ] Documentation archetype correctly identified (Python-only, C++-only, or hybrid)
- [ ] Directory structure matches convention (docs/source/ with conf.py, index.rst, welcome.rst, api.rst)
- [ ] conf.py uses correct extension stack for the archetype
- [ ] conf.py uses correct extension ordering
- [ ] Version extracted via importlib_metadata (Python/hybrid) or hardcoded (C++-only)
- [ ] Copyright uses current year and 'Sun (NeuroAI) lab' format
- [ ] Napoleon configured for Google-style only (numpy disabled)
- [ ] All sphinx_autodoc_typehints settings present and correct (Python/hybrid)
- [ ] Breathe configuration present and correct (C++/hybrid)
- [ ] html_theme set to 'furo'
- [ ] index.rst includes welcome.rst and has toctree with api
- [ ] welcome.rst follows template with correct project name and description
- [ ] welcome.rst includes Sun lab and GitHub repository links
- [ ] api.rst uses automodule with :members:, :undoc-members:, :show-inheritance: (Python)
- [ ] api.rst uses click directive with :prog: and :nested: full (Click CLIs)
- [ ] api.rst uses doxygenfile with :project: (C++ files)
- [ ] api.rst section headings are descriptive, not module paths
- [ ] No MCP server or shared asset modules included in api.rst
- [ ] Doxyfile present at project root (C++/hybrid only)
- [ ] Doxyfile outputs to docs/source/doxygen with XML generation enabled
- [ ] tox.ini [testenv:docs] follows correct pattern for archetype
- [ ] tox.ini docs command uses -j auto -v flags
- [ ] Makefile and make.bat present in docs/
- [ ] No Sphinx dependencies added directly to downstream pyproject.toml
- [ ] Documentation URL follows https://PROJECT-api-docs.netlify.app/ convention