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
Block's Rust-built, Apache-2.0 general engineering agent — now stewarded by the Linux Foundation's Agentic AI Foundation — distinguished by the deepest MCP integration in the ecosystem (70+ extensions, can also act as an MCP server) and shareable YAML 'Recipes' that scaled agent workflows to 60% of Block.
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.