By oborchers
Build and audit production-grade Python packages with best practices for project structure, tooling (pyproject.toml, Ruff, mypy), testing (pytest, CI matrices), CI/CD (GitHub Actions, trusted publishing), documentation (MkDocs, Diataxis), API design (sync/async, pluggy), packaging (wheels, sdists, cibuildwheel), versioning (SemVer, changelogs), security (Sigstore, Dependabot), and developer experience (one-command setup, Makefile).
Audit an entire Python package repository for best-practice compliance — systematically scans the codebase for structure, configuration, typing, testing, CI/CD, documentation, and security issues
Review the current Python package for best-practice violations — project structure, pyproject.toml, typing, testing, CI/CD, documentation, versioning, API design, packaging, security, and developer experience
This skill should be used when the user is designing a library's public API surface, defining __all__, organizing imports, creating an exception hierarchy, implementing async/sync dual APIs, adding plugin architecture (pluggy, entry points, protocols), applying progressive disclosure, choosing return types, naming methods, or reviewing backward compatibility. Covers __all__, underscore-prefixed modules, exception trees, httpx _BaseClient pattern, pluggy, entry points, Protocols, dependency injection, configuration patterns.
This skill should be used when the user is setting up GitHub Actions, configuring CI/CD pipelines, creating test matrices, enabling trusted publishing with OIDC, automating PyPI releases, adding Dependabot or Renovate, or configuring Sigstore attestations. Covers workflow architecture, lint/type-check/test/build/publish jobs, caching, concurrency, reusable workflows, SLSA provenance.
This skill should be used when the user is adding a CLI to a Python package, choosing between Click, Typer, and argparse, structuring cli.py or a cli/ directory, creating a __main__.py for python -m support, defining console script entry points, handling exit codes, or organizing subcommands. Covers framework selection, CLI module layout, __main__.py delegation pattern, exit code conventions, and subcommand organization.
This skill should be used when the user is configuring Ruff, setting up mypy, adding type hints, choosing between mypy and pyright, writing py.typed markers, modernizing type annotations (PEP 695/649), using TYPE_CHECKING, setting up pre-commit hooks, configuring ruff format, choosing lint rule sets, or reviewing code quality tooling. Covers Ruff rule sets, mypy strict mode, pyright, modern typing patterns, pre-commit configuration, formatting, and complexity thresholds.
This skill should be used when the user is writing a CONTRIBUTING.md, setting up developer onboarding, creating a Makefile or justfile, adding issue templates, adding PR templates, writing a README, creating a CODE_OF_CONDUCT.md, setting up CODEOWNERS, adding .editorconfig, configuring devcontainers, labeling good first issues, or building project community and governance. Covers one-command dev setup, task automation, contributor funnel, and community health files.
Uses power tools
Uses Bash, Write, or Edit tools
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Sign in to claimBased on adoption, maintenance, documentation, and repository signals. Not a security audit or endorsement.
No model invocation
Executes directly as bash, bypassing the AI model
No model invocation
Executes directly as bash, bypassing the AI model
93 skills, 15 commands, and 16 agents across 11 plugins. Opinionated, research-backed Claude Code plugins for building SaaS products that ship.

Designed for Claude Code and Cowork. Skills compatible with other AI assistants.
Building a form? Skills activate automatically.
Need an API review? /api-review
Auditing code quality? /pedantic-review
Researching a topic? /research "your question"
Stress-testing a plan? /stress-test path/to/plan.md
Compressing your CLAUDE.md? /compress path/to/file.md
If this project helps you, star the repo.
Generic AI gives you suggestions. fractional-cto gives you standards.
Each skill encodes a proven engineering principle (naming precision, API design patterns, cloud governance) and enforces it the moment Claude detects relevant work. You get the rigor of Stripe's API design, Nielsen Norman's usability research, and production cloud architecture baked into every session. No bookshelf required.
The skills are deliberately opinionated. They don't present five options and ask you to choose. They tell you what to do, cite why, and show you the code. If you disagree, edit the skill. It's just markdown.
Every plugin activates the moment your Claude session starts. A session hook fires, reads the plugin's skill index, and injects it into context. From that point on, Claude knows what principles exist and when to apply them.

Each plugin carries review checklists, good/bad pattern comparisons, working code examples, and a dedicated reviewer agent for deeper audits.
# Step 1: Add the marketplace
/plugin marketplace add oborchers/fractional-cto
# Step 2: Install individual plugins
/plugin install saas-design-principles@fractional-cto
/plugin install visual-design-principles@fractional-cto
/plugin install api-design-principles@fractional-cto
/plugin install cloud-foundation-principles@fractional-cto
/plugin install pedantic-coder@fractional-cto
/plugin install python-package@fractional-cto
/plugin install deep-research@fractional-cto
/plugin install structured-brainstorming@fractional-cto
/plugin install retell@fractional-cto
/plugin install stress-test@fractional-cto
/plugin install markdown-compressor@fractional-cto
The skills/*/SKILL.md files follow the universal skill format and work with any tool that reads it. Commands and agents are Claude-specific.
| Tool | How to use | What works |
|---|---|---|
| Gemini CLI | Copy skill folders to .gemini/skills/ | Skills only |
| OpenCode | Copy skill folders to .opencode/skills/ | Skills only |
| Cursor | Copy skill folders to .cursor/skills/ | Skills only |
| Codex CLI | Copy skill folders to .codex/skills/ | Skills only |
| Kiro | Copy skill folders to .kiro/skills/ | Skills only |
# Example: copy all skills for Gemini CLI (project-level)
for plugin in */; do
[ -d "$plugin/skills" ] && cp -r "$plugin/skills/"* .gemini/skills/ 2>/dev/null
done
claude --plugin-dir /path/to/fractional-cto/<plugin-name>
Research-backed SaaS design principles drawn from Linear, Stripe, Shopify Polaris, and Nielsen Norman Group research.
Skills (13):
npx claudepluginhub oborchers/fractional-cto --plugin python-packageStructured thinking methods that counteract LLM reasoning biases during problem exploration — first principles, inversion, constraint manipulation, perspective forcing, analogy search, and more, with user-gated parallel subagent exploration for deep dives
Adversarial plan review using red-team/blue-team agents -- generates what-if questions and grounds answers in plan artifacts with configurable tool scope
Transforms Claude Code conversation transcripts into polished, first-person blog posts through an interactive 5-stage pipeline — parse, triage, outline, draft, polish — with human editorial gates at every stage
Zero-tolerance code pedantry — naming precision, casing law, structural symmetry, import discipline, and the obsessive details that separate clean code from correct code
Research-backed, opinionated guidance for designing world-class RESTful APIs — routes, naming, errors, auth, caching, webhooks, and more, distilled from Stripe, GitHub, Twilio, Shopify, Google, and Microsoft
Python-specific validation, patterns, and expert agents
Opinionated Python 3.11+ engineering system. Establishes strong defaults (SOLID, typing policy, testing standards, code smell detection) and routes to specialist skills for TDD, CLI, web, data/science, and constrained environments.
Python technical specialists for Django, FastAPI, FastMCP, Celery, and testing
Python-specific development with type hints and idiomatic refactoring
Editorial "Python Pro" bundle for Claude Code from Antigravity Awesome Skills.
Modern Python development suite - testing, performance optimization, async patterns, and packaging