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
Anthropic's terminal-native agentic coding tool and the category-defining harness, distinguished by its layered extensibility model (CLAUDE.md memory, Agent Skills, subagents, hooks, plugins, MCP) plus permission modes, checkpoints, and optional sandboxing, available from CLI/IDE/desktop/web with an Agent SDK for building on top.
Google's fully open-source (Apache-2.0) terminal agent with a generous free tier, distinguished by built-in Google Search grounding, an extensions ecosystem bundling prompts/MCP servers/commands, GEMINI.md context files, checkpointing, and real-time voice mode.
YC-backed autonomous software engineer that picks up tickets from GitHub/Jira/Linear and opens tested PRs end-to-end across CLI, desktop, VS Code and cloud, distinguished by its own in-house Lumen model family (including on-device Scout and air-gapped sovereign variants for regulated industries like HSBC/NatWest/BAE) and the April 2026 'Swarm' feature for parallel long-horizon agents; credit-based seats at $20 (Hobby) and $200 (Professional).