$ find your agent harness

A curated, verified, cross-vendor directory of AI agent harnesses — the runtime scaffolding that turns a model into an agent.

74 harnesses profiled · 9-axis capability schema · last verified 2026-07-08

10 of 74 harnesses · sorted by stars

OpenHands · All Hands AI / OpenHands

79,895 · high

Formerly OpenDevin, the leading open-source autonomous software-engineering platform: Docker-sandboxed agents that write code, run commands, browse, and open PRs, with a production agent SDK hitting 72% on SWE-bench Verified (Claude Sonnet 4.5) and its own broader OpenHands Index benchmark launched Jan 2026.

OSS coding harnessesopen-sourcefreemium✓ mcp✓ skills✓ local modelscontainer

CrewAI · CrewAI Inc.

55,117 · high

MIT-licensed Python framework (~55k stars) for role-based multi-agent 'Crews' plus event-driven 'Flows', with unified memory, hierarchical delegation, and a commercial AMP cloud platform (free tier, Pro from ~$25/mo, enterprise) that CrewAI says powered ~2B agentic executions in the year to January 2026.

Runtimes & SDKsopen-sourcefreemium✓ mcp✓ local modelsoptional

Mastra · Mastra (Gatsby founders)

25,927 · high

The leading TypeScript agent framework (Apache 2.0 core since July 2025; some enterprise features commercial) offering agents, type-safe workflows with suspend/resume human-in-the-loop, memory, a unified router to 3,300+ models across ~94 providers, guardrails/scorers/tracing, Mastra Studio for interactive testing, and file-based agent definitions added July 2026.

Runtimes & SDKsopen-sourcefreemium✓ mcp✓ local models

Letta · Letta (formerly MemGPT, UC Berkeley spinout)

23,701 · high

Apache-2.0 platform for stateful agents descended from MemGPT, distinguished by tiered self-editing memory persisted in a database (core memory in-context, archival out-of-context) plus 2026 research on git-based 'Context Repositories' and memory-native RL; in 2026 the company is consolidating around Letta Code, an open, model-agnostic memory-first coding agent harness (LettaBot archived May 2026 and folded in as Channels).

Runtimes & SDKsopen-sourcefreemium✓ mcp✓ local modelsoptional

Amp · Sourcegraph

high

Sourcegraph's opinionated no-model-picker coding agent (CLI + VS Code extension), distinguished by curated multi-model design with specialized subagents (Oracle for reasoning, Librarian for library research), Toolboxes (UNIX-script custom tools), skills with bundled MCP servers, and an ad-supported free mode alongside zero-markup pay-as-you-go credits.

Vendor CLI agentsproprietaryfreemium✓ mcp✓ skills

Cursor (Agent mode) · Anysphere

high

VS Code-fork AI IDE whose Agent mode plus in-house Composer models, Background/Cloud Agents (isolated cloud VMs that report back as PRs), hooks, skills, and an agent SDK make it the most fully-built-out commercial agentic IDE; Composer 2 scored 61.7% on Terminal-Bench 2.0 and Composer 2.5 79.8% on SWE-bench Multilingual (SWE-bench Verified not reported).

IDE & desktopproprietaryfreemium✓ mcp✓ skillsoptional

Manus · Butterfly Effect Pte Ltd (Singapore; ex-Monica)

high

The viral general-purpose autonomous agent that plans and executes multi-step tasks in a cloud VM (browsing, code, docs, slides), notable for Wide Research parallel sub-agents and for Meta's $2B acquisition being blocked by China's NDRC in April 2026.

General / computer-useproprietaryfreemiumcloud-remote

Genspark Super Agent (+ Genspark Claw) · Genspark (MainFunc Inc.)

medium

Credit-based all-in-one 'AI employee' workspace whose Super Agent mixes multiple frontier models with 80+ tools to produce slides, sheets, sites, and calls, and whose 2026 'Genspark Claw' gives each user a persistent cloud computer commandable from WhatsApp/Telegram/Slack/Teams.

General / computer-useproprietaryfreemiumcloud-remote

Runner H · H Company (Paris)

medium

Cloud web-agent from DeepMind-alumni startup H Company ($220M seed) that orchestrates sub-agents over its own Holo vision-language action models (92.2% WebVoyager at ~$0.13/task via open-sourced Surfer-H), with Holo 3 in 2026 targeting any-UI enterprise automation.

General / computer-useproprietaryfreemium✓ local modelscloud-remote

Perplexity's Chromium-based agentic browser (free on all four platforms since April 2026) whose sidebar assistant reads pages and tabs and executes web tasks in the user's own browser, extended by 'Personal Computer' on Mac to local file editing, local computer use, and voice orchestration.

General / computer-useproprietaryfreemium
harnesses.sh — the agent harness directory