Build production-ready Node.js backend services with Express/Fastify, implementing middleware patterns, error handling, authentication, database integration, and API design best practices. Use when creating Node.js servers, REST APIs, GraphQL backends, or microservices architectures.
Create distributable Python packages with proper project structure, setup.py/pyproject.toml, and publishing to PyPI. Use when packaging Python libraries, creating CLI tools, or distributing Python code.
Master the uv package manager for fast Python dependency management, virtual environments, and modern Python project workflows. Use when setting up Python projects, managing dependencies, or optimizing Python development workflows with uv.
Master Python asyncio, concurrent programming, and async/await patterns for high-performance applications. Use when building async APIs, concurrent systems, or I/O-bound applications requiring non-blocking operations.
Python design patterns including KISS, Separation of Concerns, Single Responsibility, and composition over inheritance. Use this skill when designing a new service or component from scratch and choosing how to layer responsibilities, when refactoring a God class or monolithic function that has grown too large, when deciding whether to add a new abstraction or live with duplication, when evaluating a pull request for structural issues like tight coupling or leaking internal types, when choosing between inheritance and composition for a new class hierarchy, or when a codebase is becoming hard to test because of entangled I/O and business logic.
Python error handling patterns including input validation, exception hierarchies, and partial failure handling. Use when implementing validation logic, designing exception strategies, handling batch processing failures, or building robust APIs.
Python resilience patterns including automatic retries, exponential backoff, timeouts, and fault-tolerant decorators. Use when adding retry logic, implementing timeouts, building fault-tolerant services, or handling transient failures.
Python configuration management via environment variables and typed settings. Use when externalizing config, setting up pydantic-settings, managing secrets, or implementing environment-specific behavior.
Python project organization, module architecture, and public API design. Use when setting up new projects, organizing modules, defining public interfaces with __all__, or planning directory layouts.
Python background job patterns including task queues, workers, and event-driven architecture. Use when implementing async task processing, job queues, long-running operations, or decoupling work from request/response cycles.
Python resource management with context managers, cleanup patterns, and streaming. Use when managing connections, file handles, implementing cleanup logic, or building streaming responses with accumulated state.
Migrate Backstage plugins from Material-UI (MUI) to Backstage UI (BUI). Use this skill when migrating components, updating imports, replacing styling patterns, or converting MUI components to their BUI equivalents.
Call REST APIs from Python, parse JSON responses, and report the useful fields back to the user.
Use the existing Python execution tools as a scratchpad for calculations, data transformation, and quick script-based validation.
Describe the ideal layout of a Remix application, including canonical directories, route ownership, naming conventions, and file locations on disk. When asked to bootstrap that layout in a new directory, run the bundled TypeScript script.
Create or align a package in the Remix monorepo to match existing package conventions. Use when adding a brand new package under packages/, or when fixing an existing package's structure, test setup, TypeScript/build config, code style, and README layout to match the rest of Remix 3.
Create or update Remix repo change files under `packages/*/.changes`. Use when a user asks for release notes, a change file, a missing changelog entry, a prerelease note, or an update to existing unpublished release notes.
Publish a placeholder npm package at version 0.0.0 so package names are reserved and npm OIDC permissions can be configured before CI publishing. Use when creating a brand-new package that is not ready for full release.
Write or rewrite package README files in the style used by the Remix repository. Use when drafting a new package README, revising an existing README, or reviewing README structure, examples, installation instructions, and section ordering for Remix packages.
Ingestion pipeline architecture overview and convention reference. Use when you need a quick orientation to the pipeline framework or want to know which doctor agent to use for a specific concern.
Plan and execute incremental product isolation migrations to a facade plus contract layer in PostHog, following the Visual review architecture. Use when a product still exposes internals (models/logic/views) across boundaries and needs a safe, multi-PR migration toward contracts.py + facade/api.py + presentation separation.
Guide for exposing PostHog product endpoints as MCP tools. Use when creating new or updating API endpoints, adding MCP tool definitions, scaffolding YAML configs, or writing serializers with good descriptions. Covers the full pipeline from Django serializer to generated TypeScript tool handler.
Use when editing, reviewing, or auditing DRF viewsets and serializers in PostHog. Triggers on files in posthog/api/, products/*/backend/api/, products/*/backend/presentation/, or any file importing rest_framework serializers or viewsets. Covers OpenAPI spec quality, field typing, schema annotations, and DRF best practices that flow through the type pipeline to generated TypeScript types and MCP tools.
Build Shopify apps, extensions, themes using GraphQL Admin API, Shopify CLI, Polaris UI, and Liquid.
