The 23 Best AI Agent Open Source Tools for Your Problem in 2026

OpenCode, Sim AI, Letta Agent, Munder Difflin, treg, OpenBot by CopilotKit, MangoTart, Claude Skills Directory, Photon, AgentGit are strong paid/free AI Agent Open Source options for common problems.

OpenCode

OpenCode is an open source AI coding agent that helps you write code in your terminal, IDE, or desktop.

opencode.ai

Anomaly

05.0

Sim AI

Sim is an open-source AI workspace for building, deploying, and managing AI agents with 1,000+ integrations and every major LLM.

sim.ai

Sim

🇨🇦Canada

05.0

Letta Agent

Letta is an AI research lab building self-improving agents with persistent memory, identity, and continual learning.

letta.com

Letta

🇺🇸United States

05.0

Munder Difflin

Free, open-source multi-agent harness that creates 24/7 digital clones of you and your team.

munderdiffl.in

Munder Difflin

05.0

treg

treg is an open-source tool catalog for AI agents, providing one key to access 2,630 API endpoints across 47 providers.

treg.to

treg

05.0

OpenBot by CopilotKit

Enterprise-ready frontend stack for building agent-native applications that connect any AI agent to any user surface.

copilotkit.ai

Tawkit

05.0

MangoTart

A dedicated computer for AI agents with Hermes preinstalled, persistent browser, local console, and recovery controls on hardware you own.

mangot.art

MangoTart

🇸🇬Singapore

05.0

Claude Skills Directory

A curated directory of agent skills and workflows for Claude, Claude Code, Codex & Cursor — browse, download, and contribute in minutes.

claudeskills.club

2026 Claude Skills Directory. Built for the Claude Co

05.0

Photon

Open-source framework that connects AI agents to iMessage, WhatsApp, Telegram, Slack, Discord, SMS/RCS, and more.

photon.codes

Photon

05.0

AgentGit

AgentGit is version control for AI agent sessions, letting teams track, share, and manage agent workspaces.

agent-git.com

Einsia

🇸🇬Singapore

05.0

Agent AFK

The open-source coding agent you don’t have to watch. Start a task and walk away.

agentafk.com

Agent AFK

05.0

Polygres

Polygres turns the Postgres you already run into internal search for AI agents.

polygres.com

Polygres

05.0

Omnara

Omnara is an open-source platform providing a single API for building durable, secure agents, as an alternative to Claude Managed Agents.

omnara.com

Omnara

05.0

InitRunner

Open-source CLI to define AI agents as YAML and run them from the terminal.

initrunner.ai

InitRunner

🇨🇭Switzerland

05.0

Chirpz AI

An applied AI lab solving agent engineering, building tools for reliable and observable AI agents.

chirpz.ai

Chirpz AI

05.0

AdminForth

Agent-first open-source admin panel framework for building robust back-office panels with full code control.

adminforth.dev

AdminForth

05.0

nexu

nexu is an open-source OpenClaw desktop app for Feishu, offering one-minute setup, local data, and multi-model support.

nexu.io

Nexu

05.0

Skillry

Skillry is a curated library of Agent Skills for Claude Code, Codex, Cursor and other AI coding agents.

skillry.dev

Skillry

05.0

Agenta

Agenta is the open-source workspace for building, evaluating, and shipping AI agents and automations.

agenta.ai

Agenta

05.0

heyCLI

heyCLI translates natural language into Linux commands, acting as your copilot for the command line.

heycli.com

05.0

Pinokio

1-click launch any open-source app.

pinokio.computer

Pinokio

05.0

ClawDaddy

Managed hosting for AI agents, deploy OpenClaw or Hermes on private servers in minutes.

clawdaddy.run

🇺🇸United States

05.0

Plasma AI

Plasma AI builds infrastructure for intelligence at scale, turning agent fleets into coordinated workforces.

plasma.ai

Plasma AI

🇺🇸United States

05.0