Best AI Agent Frameworks Tools

Frameworks for building and orchestrating agentic LLM applications: tool use, multi-agent workflows, memory, planning, and evaluation.

AI agent frameworks provide the building blocks for constructing applications that combine large language models with tool use, memory, planning, and multi-agent coordination. They abstract common patterns such as retrieval-augmented generation, tool invocation, and workflow orchestration, allowing developers to focus on domain logic. Both open-source and commercial options exist, ranging from lightweight libraries to hosted platforms that add monitoring, scaling, and evaluation services. Selection typically depends on factors like community support, extensibility, licensing, and integration with existing infrastructure.

Top Open Source AI Agent Frameworks platforms

View all 20+ open-source options
Browser Use logo

Browser Use

LLM-driven, stealth-enabled browser automation with cloud scaling

Stars
79,825
License
MIT
Last commit
1 day ago
PythonActive
CrewAI logo

CrewAI

Lightning‑fast Python framework for autonomous multi‑agent automation

Stars
45,341
License
MIT
Last commit
23 hours ago
PythonActive
Composio logo

Composio

Unified SDKs to empower AI agents with real‑world tools

Stars
27,308
License
MIT
Last commit
14 hours ago
TypeScriptActive
smolagents logo

smolagents

Run sandboxed code agents with minimal code and any LLM

Stars
25,795
License
Apache-2.0
Last commit
21 hours ago
PythonActive
LangGraph logo

LangGraph

Orchestrate resilient, stateful language agents with graph‑based workflows

Stars
25,777
License
MIT
Last commit
21 hours ago
PythonActive
Mastra logo

Mastra

TypeScript framework for building scalable AI agents and workflows

Stars
21,771
License
Last commit
15 hours ago
TypeScriptActive
Most starred project
79,825★

LLM-driven, stealth-enabled browser automation with cloud scaling

Recently updated
13 hours ago

Skyvern automates browser-based tasks using LLMs and computer vision, eliminating brittle selectors. Deploy locally or via Skyvern Cloud, with Python and TypeScript SDKs for seamless integration.

Dominant language
Python • 8 projects

Expect a strong Python presence among maintained projects.

What to evaluate

  1. 01Extensibility and Plug-in Architecture

    Assess whether the framework supports easy addition of custom tools, memory stores, and planners, and whether it offers a clear API for extending core functionality.

  2. 02Multi-Agent Coordination

    Evaluate built-in support for orchestrating multiple agents, including message passing, role assignment, and conflict resolution mechanisms.

  3. 03Evaluation and Monitoring Capabilities

    Look for features that enable systematic testing, performance metrics, and runtime monitoring of agent behavior, especially for commercial SaaS offerings.

  4. 04Community and Documentation

    Consider the size of the contributor base, frequency of releases, and quality of tutorials or reference implementations.

  5. 05Deployment Flexibility

    Check if the framework can be deployed on-premises, in containers, or as a managed service, and whether it integrates with common cloud AI stacks.

Common capabilities

Most tools in this category support these baseline capabilities.

  • LLM integration layer
  • Tool invocation API
  • Memory management (short-term, long-term)
  • Planning and task decomposition
  • Multi-agent orchestration engine
  • Retrieval-augmented generation support
  • Evaluation harness for agent runs
  • Extensible plug-in system
  • Logging and observability hooks
  • Support for both open-source and SaaS deployment

Leading AI Agent Frameworks SaaS platforms

CrewAI logo

CrewAI

Multi-agent automation framework & studio to build and run AI crews

AI Agent Frameworks
Alternatives tracked
15 alternatives
LangGraph logo

LangGraph

Open-source framework for building stateful, long-running AI agents

AI Agent Frameworks
Alternatives tracked
14 alternatives
Relevance AI logo

Relevance AI

No-code platform to build a team of AI agents with rich integrations

AI Agent Frameworks
Alternatives tracked
16 alternatives
Most compared product
10+ open-source alternatives

Relevance AI helps ops and GTM teams assemble an 'AI workforce'—customizable agents with templates and automations that plug into your stack (Zapier, Snowflake, and more) to research, create, and execute tasks across workflows.

Leading hosted platforms

Frequently replaced when teams want private deployments and lower TCO.

Typical usage patterns

  1. 01Tool-Augmented Question Answering

    Agents retrieve external data via APIs or databases, combine it with LLM reasoning, and return enriched answers.

  2. 02Workflow Automation

    Sequences of agents perform discrete steps-data extraction, transformation, validation-automating complex business processes.

  3. 03Collaborative Decision Support

    Multiple specialized agents propose alternatives, critique each other's suggestions, and converge on a recommendation.

  4. 04Dynamic Code Generation

    Agents generate, test, and iterate code snippets, leveraging tool execution environments to validate outputs.

  5. 05Customer Service Orchestration

    A front-line conversational agent routes queries to domain-specific agents (billing, technical support) and aggregates responses.

Frequent questions

What distinguishes an AI agent framework from a standard LLM library?

An AI agent framework adds orchestration, tool use, memory, and planning capabilities on top of raw LLM calls, enabling more autonomous and interactive applications.

Can I use open-source frameworks for commercial products?

Yes, most open-source projects are released under permissive licenses, but you should review the specific license (e.g., MIT, Apache) to ensure compliance.

How do SaaS agent platforms differ from self-hosted options?

SaaS platforms typically provide managed hosting, built-in monitoring, and scaling, while self-hosted frameworks require you to provision infrastructure but offer greater control.

What role does memory play in agentic applications?

Memory stores context across turns, allowing agents to reference prior interactions, maintain state, and improve continuity in multi-step tasks.

Is it possible to combine multiple agents in a single workflow?

Yes, most frameworks support multi-agent workflows where agents can pass messages, delegate subtasks, and aggregate results.

How is evaluation of agent behavior typically performed?

Frameworks often include test harnesses, logging, and metrics (e.g., success rate, latency) that let developers benchmark and iterate on agent performance.