Anthropic API
Claude API access for long-context reasoning, coding, tools, and enterprise-safe AI apps.
LLM Providers & APIs
Paid4.8
§ Recipe
Build an AI agent from scratch.
Most agent tutorials are toys. A real agent has memory, tool use, guardrails, and observability. This is the stack that survives week two, not just the launch tweet.
Serious scale
Reasoning engine
01Claude's tool-calling and long-context behavior is the most reliable substrate for agents that need to reason over documents and invoke tools in sequence without going off the rails.
Orchestration framework
02LangChain
The most popular framework for building LLM applications — chains, agents, and RAG made easy.
AI AgentsOpen source4.4Batteries-included patterns for chains, memory, retries, and tool routing. You'll outgrow it — but it saves six weeks of scaffolding you don't want to write.
RAG layer
03LlamaIndex
Data framework and managed services for RAG, agents, document parsing, and knowledge apps.
AI AgentsFreemium4.3If your agent needs to know your data, LlamaIndex is the fastest path from documents to a production retrieval pipeline. Better defaults than rolling your own.
Tool access
04Composio
MCP gateway and integration layer connecting agents to 1,000+ toolkits with managed auth.
MCP & Skills PlatformsFreemium4.2Instead of writing OAuth flows for every third-party integration, Composio gives your agent 200+ pre-wired tools. You go from GitHub-Slack-Notion in a day.
Multi-agent coordination
05CrewAI
Multi-agent framework and platform for orchestrating role-based AI crews.
AI AgentsOpen source4.3When one agent isn't enough. CrewAI's role-based coordination beats hand-rolled message passing when you need researcher-plus-writer-plus-reviewer workflows.
Inference for sub-tasks
06Groq
Ultra-fast LLM inference for chat, agents, audio, and open model workloads.
LLM Providers & APIsFreemium4.5For the low-stakes reasoning inside the loop — classification, routing, summarization — Groq's LPU inference is 10x cheaper and 5x faster than frontier model calls. Use it everywhere it's good enough.