The Coding Agent Harness Directory (August 2026)
Published August 22, 2026 · by the AQ team
This is a directory of coding agent harnesses and the tools that orchestrate them, checked against each vendor's own site in August 2026. It covers four shapes: CLIs built by model labs, open-source model-neutral harnesses, desktop apps that run several harnesses in parallel, and cloud platforms that run agents on hosted machines. It also lists what shut down or was replaced this year, the part every static awesome-list gets wrong: two well-known entries died in February 2026 alone. For the definition of the term, read what is a coding harness; for a decision framework, read how to choose one. This page is the map.
How to read this directory
Four facets separate these tools better than feature lists:
- Execution locus. Where the agent runs: your laptop, a VM you own, or the vendor's cloud. This decides who holds your code and credentials.
- Model access. A subscription sign-in (Claude, ChatGPT), your own API keys, or local open-weight models.
- Multiplayer access. Whether a second person can see or join a running session.
- Persistence. Whether the session survives a closed laptop or a reboot.
CLIs from the model labs
Each lab now ships its own harness, tuned for its own models. All of these run locally in your terminal by default, so persistence is your problem (see keeping sessions alive past a closed laptop).
| Harness | Built by | Model access | Notes (as of August 2026) |
|---|---|---|---|
| Claude Code | Anthropic | Claude Pro/Max plan, Team/Enterprise premium seat, or API key | Terminal, IDE extensions, desktop app, and the web at claude.ai/code; macOS, Linux, Windows |
| Codex CLI | OpenAI | ChatGPT plan sign-in or API key | Open-source terminal agent; one account also covers Codex in ChatGPT, the editor, and the cloud |
| Antigravity CLI | Google account plans | The agy command; replaced Gemini CLI, which Google shut down for free, Pro, and Ultra users on June 18, 2026; multi-agent by default, with skills, hooks, and MCP support | |
| Grok Build | xAI | SuperGrok or X Premium Plus subscription | Announced May 25, 2026 as an early beta; open-source TUI in Rust, with plan mode, headless CI use, and editor embedding over ACP |
| Kimi Code CLI | Moonshot AI | Kimi models by default; other compatible providers configurable | MIT-licensed TypeScript agent with built-in coder, explore, and plan subagents; succeeds the earlier kimi-cli |
| Amp | Amp (ampcode.com) | Amp account | Runs on the web, in the terminal, and on a phone; threads run in orbs, per-thread machines billed by the minute, and workspace members can join a thread while it runs; see AQ vs Amp |
Open-source, model-neutral harnesses
These decouple the harness from the model vendor: bring an API key, a subscription, or a locally served open-weight model.
| Harness | Shape | Notes (as of August 2026) |
|---|---|---|
| OpenCode | Terminal, IDE, or desktop app | Connects to any provider with your own keys, including local models; optional OpenCode Go subscription ($5 first month, then $10 per month) for hosted open-source models |
| Pi | Minimal terminal harness | Ships four tools and a system prompt under 1,000 tokens; everything else arrives as extensions, skills, and packages shared over npm or git |
| Aider | Terminal pair programmer | Among the oldest harnesses still in wide use; connects to most LLMs including local ones and git-commits every change |
| Goose | Local agent framework | Started at Block, now under the Agentic AI Foundation; model-configurable, extends through MCP |
| OpenHands | CLI, browser client, and agent server | MIT-licensed and model-agnostic; runs locally, self-hosted, or on its managed cloud |
Desktop apps that run harnesses in parallel
These are orchestrators rather than harnesses: they run the stock CLIs side by side on your machine, usually one git worktree per task. This layer, the harness of harnesses, is where churn is fastest.
| Tool | Platforms | Notes (as of August 2026) |
|---|---|---|
| Conductor | macOS | Runs Claude Code, Codex, Cursor, and OpenCode in parallel, each workspace in its own worktree |
| Emdash | macOS, Windows, Linux | Free and open source (YC W26); one worktree per task, works with 25+ CLI agents |
| Superset | Desktop | Pitches running 100+ parallel coding agents on your machine |
| Proliferate | Desktop, self-hostable | Open-source IDE for Claude Code, Codex, and OpenCode; runs agents in parallel, locally or in the cloud |
| Xirp | Web dashboard over local sessions | Spotify's vendor-neutral agentic development environment, opened as a free public beta on August 10, 2026; manages Claude Code, Codex, and Gemini CLI sessions, one working tree per session |
| Vibe Kanban | Desktop, open source | Kanban board over parallel agents with automatic worktrees; sunsetting as a company, continuing as community-maintained open source |
Cloud platforms that run agents on hosted machines
Here execution moves off your machine: the vendor provisions a sandbox, runs the agent, and hands back a pull request.
| Platform | Vendor | Notes (as of August 2026) |
|---|---|---|
| Claude Code on the web | Anthropic | Claude Code sessions in Anthropic-managed sandboxes, at claude.ai/code |
| Codex cloud | OpenAI | Runs many tasks in parallel, each in its own cloud sandbox preloaded with your repository |
| Cursor cloud agents | Cursor | Agents in isolated VMs; hand a CLI conversation to the cloud by prefixing a message with an ampersand, resume on web or mobile |
| Copilot coding agent | GitHub | Assign an issue to Copilot; it boots a GitHub Actions VM, writes the code, and opens a PR |
| Devin | Cognition | Autonomous engineer with a sandboxed VM per session; runs many tasks in parallel |
| Warp Oz | Warp | Launched February 2026; cloud agents in Docker sandboxes, driven by Claude Code, Codex, or Warp's own harness |
| Superconductor | Superconductor | Cloud workspace running Claude Code, Codex, Pi, Amp, and others in parallel, with previews and one-click PRs from phone or desktop |
Gone this year: the churn a directory has to track
This market retires tools faster than lists update. Status checked on each vendor's own site in August 2026:
- Terragon shut down on February 9, 2026; its own docs now point users at Claude Code on the web.
- Crystal was deprecated on February 26, 2026 and receives no further updates; its maker, Stravu, ships Nimbalyst as the successor.
- Gemini CLI was shut down for free, Pro, and Ultra users on June 18, 2026, replaced by the Antigravity CLI.
- kimi-cli was succeeded by Kimi Code CLI, which migrates its configuration and sessions.
- Vibe Kanban is sunsetting as a product and continuing as community-maintained open source.
One adjacent entry worth knowing: qm, the MIT-licensed multiplayer agent harness Y Combinator open-sourced in July 2026, gives every employee a work agent over Slack and the web, driven by Pi, OpenCode, Codex, or Claude Code at its core. It is a company-wide work harness rather than a coding harness, and a sign of where the vocabulary is heading.
The facet the directory keeps surfacing: who sees the work
Scan the tables and a pattern shows: nearly everything local is single-player, and nearly everything multiplayer runs on the vendor's cloud. The default matters: a July 2026 LeadDev analysis of 25,264 agent-generated pull requests across 2,361 popular GitHub repositories found that in 79 percent of agentic PRs the same developer both reviewed and modified the agent's contribution, and only about one in eight workflows involved multiple humans. When a session is invisible, the only reviewable artifact is the diff, and the person closest to the diff is the person who prompted it. The missing quadrant, multiplayer sessions on infrastructure you own, is what multiplayer coding agents names.
Where AQ fits
AQ is the multiplayer coding harness where engineering teams run AI coding agents like Claude Code and Codex together: shared live terminals, a code editor, and app previews, in your own cloud. In this directory's facets, AQ sits in that missing quadrant. It is not another harness: agents run as the real CLIs (Claude Code, Codex, Cursor Agent, Kimi, Grok, or plain shells) in persistent tmux sessions on your team's VM, streamed live to the browser. Sessions survive a closed laptop and resume from any device, each workspace gets one isolated git worktree, and teammates open the same workspace and watch the same live session (typing into someone else's terminal happens only after its owner approves a control request in one click; visibility is owner-managed, team-visible or private and shared with specific people).
Model access stays as the tables describe: each engineer signs into the CLIs with their own Claude or OpenAI account, and AQ never marks up model usage. Agents commit, push, and open PRs with per-user GitHub auth, every workspace can serve a live dev-server preview with links that are viewable without an account, and Linear issues become workspaces by labeling them ai-task, with a human starting the agent, never an auto-launch.
Pricing is two plans: Free is a personal sandbox for one person (AQ creates a private machine in an isolated network, nothing to install, no time limit), and Team is $50 per user per month in early access (standard $200, billed monthly), covering VMs you connect from your own cloud or a dedicated always-on AQ-managed VM in its own isolated network, with your rate locked for your first 12 months.
Plainly: pick any harness from the tables above, or several. AQ is the layer that makes whichever ones your team picks persistent, isolated, and visible to more than one person, without moving execution into someone else's cloud.
Frequently asked questions
What is a coding agent harness?
The software wrapped around a language model that turns it into a working coding agent: the system prompt, tool definitions, context management, execution loop, and failure handling. Claude Code, Codex CLI, OpenCode, and Pi are all harnesses; the model underneath supplies the reasoning. The glossary page covers the term in depth, including why the same model scores differently in different harnesses.
Which coding agent harnesses are open source?
As of August 2026: Codex CLI, OpenCode, Pi, Aider, Goose, OpenHands, Kimi Code CLI, and Grok Build among the harnesses themselves, plus Emdash, Proliferate, and Vibe Kanban among the tools that orchestrate them. Claude Code, Amp, and the cloud platforms (Devin, Warp Oz, Superconductor) are proprietary. Open source here usually means the harness code; the frontier models it drives remain hosted APIs unless you serve open-weight models yourself.
Which coding agent tools shut down or were replaced in 2026?
Terragon shut down on February 9, 2026, and Crystal was deprecated on February 26, 2026 (its maker now ships Nimbalyst). Google shut down Gemini CLI for free, Pro, and Ultra users on June 18, 2026, replacing it with the Antigravity CLI, and Moonshot AI succeeded kimi-cli with Kimi Code CLI. Vibe Kanban is sunsetting as a company and continuing as community-maintained open source. Check the vendor's own site before adopting anything in this category.
Can I run multiple harnesses against the same repository?
Yes, and it is increasingly the norm rather than the exception. The safe pattern is one git worktree per session, so parallel agents never edit the same checkout: desktop orchestrators like Conductor and Emdash automate exactly that on one machine, and AQ does it on a team VM, where each workspace is an isolated worktree and any CLI can run inside it. Keep shared instruction files (CLAUDE.md, AGENTS.md) consistent across the harnesses you use.
Which coding harness should I choose?
Start from your model access: an Anthropic subscription points at Claude Code, a ChatGPT plan at Codex CLI, own keys or local models at OpenCode or Pi. Then run a small bake-off on your own repository rather than trusting benchmarks, because scores are earned by a model and harness pairing, not a model. The chooser guide walks the full decision, and treats the harness as a per-engineer pick you revisit as models change.