AI Development Tools for Building AI Apps

Open directory and leaderboard for reusable AI agent skills. Discover and install modular capabilities that enhance AI coding agents with procedural knowledge through simple one-command installation.

Open registry for verified agent skills with 3,500+ skills. Discover and install quality-focused skills for Claude Code, Cursor, Windsurf, and other AI coding agents with community verification.

Massive agent skills marketplace with 71,000+ skills compatible with Claude Code, OpenAI Codex CLI, and ChatGPT. Uses the open standard SKILL.md format with smart search and category filtering.

Agent skills directory with focus on Claude, ChatGPT, and Codex. Discover, retrieve, and install reusable AI agent capabilities with step-by-step installation guides for multiple AI platforms.

Web scraping API that converts any webpage into clean Markdown or structured JSON for AI consumption. Features intelligent crawling, AI-powered extraction, and JavaScript rendering for building AI-ready data pipelines.

Open-source CLI tool that generates entire codebases from natural-language prompts. Supports OpenAI, Anthropic, and open-source models with customizable agent identity and vision input for diagrams.

Open-source multi-agent AI framework that runs in a Dockerized sandbox with code execution, browser automation, subordinate agents, and a memory system for building autonomous coding and research workflows.

Unified LLM gateway providing OpenAI-compatible API access to 500+ models from 60+ providers. Pay-as-you-go pricing with no markup on model rates, automatic fallbacks, and routing optimizations.

Open-source LLM observability and engineering platform for tracing, evaluating, and debugging AI applications. Langfuse provides production-grade monitoring with trace spans, cost tracking, prompt management, evaluation datasets, and a playground — all with no per-seat fees and a self-hostable MIT-licensed core.

Community prompt and chain repository integrated with LangSmith. LangChain Hub lets developers discover, share, and version-control prompt templates, agent configurations, and chain definitions — a prompt registry that connects directly to the LangChain ecosystem for rapid AI prototyping.

Official collection of Jupyter notebooks and code recipes from Anthropic for building with the Claude API. Covers tool use, MCP integration, agent patterns, extended thinking, RAG, prompt caching, multimodal capabilities, and production patterns.

Official collection of guides, quickstarts, and Jupyter notebooks from Google for building with the Gemini API. Covers multimodal prompting, function calling, grounding with Google Search, context caching, audio/video understanding, and agent patterns.

Open-source SDK from Microsoft for integrating LLMs into applications using C#, Python, and Java. Semantic Kernel provides an agent framework, plugin architecture, prompt template engine, planner, and memory connectors — designed for enterprise AI orchestration with Azure OpenAI and other providers.

Local MCP server that bridges API documentation with AI coding assistants, letting you query specs in natural language and generate type-safe code directly from Apidog projects or OpenAPI files.

macOS-native context engineering app that lets you visually select files and code from local repos, build structured AI prompts, and apply model-generated edits with reviewable diffs.