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Harnesses

Author
Tom Rochette
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Created: / Updated: / Status: in progress / Readability: 3 / 6 minutes read (~1071 words)
agents 48 harnesses 35
Table of Contents

The terminal and CLI agents that carry the model into your repository: the platform benchmarks, the provider entrants, and the minimal, self-extensible, and foundation-governed outliers.

  • aider - the pre-agentic BYOK pair-programmer, cheapest precise-edit tool, development stalled since May 2026.
  • Amp - Sourcegraph-spun-out agent whose orbs keep working after you close the laptop, free on your own compute, subscriptions, or keys since September 13.
  • Ante - Antigma Labs’ ~15MB Rust harness with an embedded llama.cpp engine, offline GGUF or 12+ cloud providers, footprint as the product.
  • Atomic Agent - AtomicBot-ai’s MIT local-first harness over its own TurboQuant llama.cpp fork, grammar-constrained tool calls and Fusion worker pool built so small models survive long runs.
  • AutoDev - Phodal’s MPL-2.0 Kotlin Multiplatform agent platform, five agents and nine subagents across IDEA, VS Code, CLI, web, and mobile, Xiuper 3.0 still alpha under a one-person bus factor.
  • Avante.nvim - the Apache-2.0 Neovim plugin running a Cursor-style agentic loop in the editor with bring-your-own providers, 18.2k stars and a 300-point launch thread behind it.
  • Bullet - TryBullet’s closed-source YC S26 latency bet, free today, with a published 479-of-500 SWE-bench run.
  • Claude Code - Anthropic’s everywhere-at-once harness, the platform benchmark and the token-cost cautionary tale.
  • Cline - the open-source agent that outgrew its VS Code extension into CLI, kanban, and SDK, 5.5 million installs deep.
  • Codex - OpenAI’s ChatGPT-included agent, the Apache-2.0 big-lab CLI individuals can still just run.
  • Command Code - the ex-Langbase closed harness whose taste-1 model learns your conventions, credit plans from $1 a month built on open models.
  • Copilot CLI - GitHub’s proprietary terminal agent included in every Copilot plan, first-party GitHub.com reach, preview sandboxes, multi-model credits.
  • Crush - Charm’s Go-and-LSP terminal agent, FSL-licensed, from the original OpenCode repo.
  • DeepSeek Harness - DeepSeek’s everything-is-a-plugin harness, 247.8k stars as of 2026-10-12, MIT, prerelease-only at dsh-v0.2.1-alpha.2.
  • Exo - the MIT self-modification bet, a harness the agent can rewrite at runtime, cheapest measured harness at $1.05 per task.
  • fx - Vercel Labs’ ~6 MiB Zig harness built to be embedded, the first agent-as-a-dependency bet.
  • Gemini CLI - Google’s open-source terminal agent, superseded for individuals by Antigravity CLI in June 2026.
  • goose - Block’s Rust agent turned Linux Foundation project, the field’s first foundation-governed harness.
  • gptme - the 2023-vintage MIT terminal agent, the category’s oldest codebase, whose git-based persistent-agent layer and cross-harness memory make it the autonomous-coworker bet.
  • Grok Build - SpaceXAI’s Apache-2.0 Rust TUI agent, open-sourced to a 590-point thread, monorepo-synced releases, the wire-level privacy analysis attached.
  • jcode - Solo Systems’ Rust harness for parallel agents, RAM floor, native memory and swarm, self-dev included.
  • Juggler - Julian Storer’s AGPL Go GUI agent, conversations as branchable trees with every tool call inspectable.
  • Junie - JetBrains’ plan-first agent with BYOK, IDE-grade grounding, and a free on-device Local mode for Mac.
  • Kilo Code - the Cline-and-Roo feature-merge under MIT, subagents through cloud tasks bundled in, Anaconda’s since July 2026.
  • Kimi Code - Moonshot AI’s terminal agent tuned for its own challenger-priced models, subagents through ACP in one Node.js CLI.
  • LongHorizon-Harness - Alibaba DreamX’s MIT audited computer-use loop wrapping Claude Code, Codex, OpenCode, and DeepSeek Harness as backends, quiet since its August paper.
  • MiMo Code - Xiaomi’s MIT OpenCode fork, a terminal agent built around checkpointed memory and goal-verified long-horizon runs, priced on cheap MiMo tokens.
  • Mini-SWE-agent - the SWE-bench team’s roughly-100-line Python baseline harness, 11.6 million PyPI downloads a month, the project its own parent repository now supersedes SWE-agent with.
  • Nanocoder - the Nano Collective’s community-built local-first agent, MIT via npm with the widest documented local-engine list, funded by sponsors instead of a company.
  • Oh My Pi - Stencil Labs’ batteries-included Pi fork with LSP and a real debugger wired into the loop, 35.2k stars past its frozen-core parent.
  • Omnigent - Databricks’ Apache-2.0 meta-harness wrapping Claude Code, Codex, Cursor, OpenCode, Pi, and custom YAML agents behind one API, with policies, sandboxes, and live session sharing.
  • OmO - the source-available 70k-star terminal agent on its senpi Pi fork (memory, CodeMode, ultracode, Herdr DAG side pane), the scale-versus-trust test case with a custom per-portion license and an AI-persona maintainer.
  • OneCLI - the YC S26 Apache-2.0 team harness where a credential gateway injects secrets per request, so agents never hold them.
  • Open Interpreter - a 2026 Rust fork of Codex CLI emulating provider harnesses for cheap open-weight models like Kimi K3 and GLM.
  • OpenCode - the MIT, provider-neutral harness with the leanest measured token baseline.
  • OpenHands - the renamed OpenDevin platform bet, sandboxed code-shell-browser agents you can self-host.
  • Pi - Earendil’s minimal, self-extensible harness, a frozen core plus your TypeScript extensions, MCP arriving as a built-in extension in the v0.99 line.
  • Qwen Code - Alibaba’s Gemini CLI fork and open-weights showcase, its OAuth free tier discontinued April 2026.
  • Unreal Agent - Unreal Labs’ async-first MIT Go harness, background tool calls as the cost thesis, exo-class traction at day three.
  • Warp Agent CLI - Warp’s terminal agent unbundled into any terminal, model routing, cloud agents, and orchestration behind its credit meter.
  • ZCode - Z.ai’s official GLM workbench, caught silently uploading whole workspaces in September 2026 and open-sourced three days later as a flattened dump.
  • Zerostack - the solo GPL-3.0 Rust agent, 26 MB binary and ~16 MB RAM, subagents, worktrees, hooks, MCP behind compile flags.

Its members are compared on shared rows in the Harness Feature Matrix.

Changes
#

  • 2026-08-22 - Added aider.
  • 2026-08-22 - Added Amp.
  • 2026-08-22 - Added Claude Code.
  • 2026-08-22 - Added Codex.
  • 2026-08-22 - Added Crush.
  • 2026-08-22 - Added Gemini CLI.
  • 2026-08-22 - Added Junie.
  • 2026-08-22 - Added OpenCode.
  • 2026-08-24 - Added Cline.
  • 2026-08-24 - Added goose.
  • 2026-08-24 - Added Qwen Code.
  • 2026-08-27 - Added Kilo Code.
  • 2026-08-27 - Added OpenHands.
  • 2026-08-29 - Added fx.
  • 2026-08-30 - Added Ante.
  • 2026-08-30 - Added Bullet.
  • 2026-08-30 - Added DeepSeek Harness.
  • 2026-08-30 - Added jcode.
  • 2026-08-30 - Added Juggler.
  • 2026-08-30 - Added OneCLI.
  • 2026-08-30 - Added Pi.
  • 2026-08-30 - Added Warp Agent CLI.
  • 2026-08-30 - Added Zerostack.
  • 2026-09-05 - Added Exo.
  • 2026-09-05 - Added Kimi Code.
  • 2026-09-12 - Added Grok Build.
  • 2026-09-21 - Added ZCode.
  • 2026-09-25 - Added Unreal Agent.
  • 2026-09-27 - Added Open Interpreter.
  • 2026-09-27 - Added MiMo Code.
  • 2026-10-05 - Added Command Code.
  • 2026-10-05 - Added Copilot CLI.
  • 2026-10-06 - Added Omnigent.
  • 2026-10-08 - Added Nanocoder.
  • 2026-10-10 - Added Mini-SWE-agent.
  • 2026-10-10 - Added Oh My Pi.
  • 2026-10-10 - Added Atomic Agent.
  • 2026-10-13 - Added Avante.nvim.
  • 2026-10-13 - Added OmO.
  • 2026-10-13 - Added AutoDev.
  • 2026-10-13 - Added gptme.
  • 2026-10-13 - Added LongHorizon-Harness.