$ 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

1 of 74 harnesses · sorted by stars

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