Summary

The repository has no CI enforcement for Python code quality. All existing languages (Markdown, PowerShell, YAML) have dedicated linting workflows called from the pr-validation.yml orchestrator. Adding a Python linting workflow with ruff closes this gap and satisfies the OSSF Best Practices coding_standards_enforced MUST criterion for silver badge compliance.

Context

The CI architecture uses reusable workflows stored at .github/workflows/.yml called by a pr-validation.yml orchestrator. Each reusable workflow accepts standard inputs like soft-fail (boolean, allows workflow to pass even if linting fails) and changed-files-only (boolean, scopes checks to files changed in the PR). This pattern was established through prior CI expansion work (#634, closed).

Ruff is the project's chosen Python linter and formatter, as configured in uv-projects.instructions.md and the Python coding standards. It provides both linting (ruff check) and format checking (ruff format --check) in a single fast tool.

This workflow has HIGH OSSF impact. Without CI-enforced linting for Python, adding Python as a supported language puts the coding_standards_enforced MUST criterion at risk, potentially affecting the silver badge.

Architecture: Multi-Skill Working Directory

The reusable workflow should accept a working-directory input parameter so the orchestrator can call it once per Python skill directory:

on:
  workflow_call:
    inputs:
      working-directory:
        type: string
        required: false
        default: ".github/skills/experimental/powerpoint"
      soft-fail:
        type: boolean
        required: false
        default: false
      changed-files-only:
        type: boolean
        required: false
        default: false

The orchestrator (pr-validation.yml) calls this workflow once per Python skill directory. When a second Python skill is added, the orchestrator gains another job pointing to that skill's directory, with no changes to the reusable workflow itself. Each skill's pyproject.toml contains its own [tool.ruff] configuration, so ruff discovers the correct settings when run in the skill's working directory.

Changes Required

The new workflow should follow the established reusable workflow pattern:

• Accept soft-fail, changed-files-only, and working-directory inputs
• Install uv and run uv sync --locked in the specified working directory for dependencies
• Run ruff check with appropriate configuration
• Run ruff format --check to verify formatting
• Output results in a structured format consistent with other linting workflows

Acceptance Criteria

• .github/workflows/python-lint.yml exists as a reusable workflow
• Workflow accepts soft-fail, changed-files-only, and working-directory standard inputs
• ruff check runs against Python files and reports violations
• ruff format --check verifies formatting compliance
• pr-validation.yml calls the new workflow as a job in the validation matrix
• Workflow passes when no Python files are changed (changed-files-only mode)
• Workflow correctly reports failures when ruff finds violations
• soft-fail mode allows the workflow to pass with warnings rather than failures
• Adding a new Python skill requires only a new orchestrator job entry, no workflow changes

OSSF Impact

Dependencies

• Benefits from uv being pre-installed (feat(devcontainer): Add Python development extensions and uv package manager #887, feat(ci): Add uv and Python package sync to copilot-setup-steps #888) but can install uv within the workflow itself
• Benefits from npm scripts (feat(scripts): Add npm run scripts for Python linting and testing #886) but can invoke ruff directly

Related

• PR feat(skills): add PowerPoint automation skill with YAML-driven deck generation #868 — PowerPoint automation skill (first Python skill)
• feat(ci): Add Python file extensions to copyright/SPDX header validation #883 — Copyright/SPDX header validation for Python
• feat(ci): Add Python to CodeQL analysis language matrix #884 — CodeQL Python integration
• feat(scripts): Add npm run scripts for Python linting and testing #886 — npm scripts for Python
• feat(skills): Mandate unit testing, extend CI coverage, and document language support process #634 — Prior CI coverage expansion work (closed)