AI · alternatives · 2026
24 alternatives to Zenith: sota harness for normal models to beat Fable on FrontierSWE
Zenith is our long-running agent harness. On Frontier SWE — seventeen of the hardest public long-horizon software-engineering tasks we know of — Zenith took GPT-5.5 from 5th place to 1st, ahead of Claude Fable, by building the right harness around the model instead of swapping in a bigger one.
Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes. Prices are shown for the 3 we have checked on their own sites, 3 of them free or with a free tier.
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HarnessRouter Community Editionfree tier, from $20/mo▲397Open-source unified interface for agent harnesses
Aug 2026 · harnessrouter.ai · its alternatives →
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Harness by Autonomousfree tier, from $149/mo▲295Every coding agent, every machine, one command center.
9d ago · autonomous.ai · its alternatives →
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A few days ago I found myself trying out GLM 5.2 and was really positively impressed. The capabilities and security I was getting from this LLM are similar to those I've gotten from models like Claude or GPT, and this really surprised me. But then I thought, "I wonder how it would work on a normal computer like mine," and above all, "I wonder if it would work without going into OOM on a computer like mine." So I started working with the help of agents to test this possibility. I started converting the model to int4, understanding MTP usage, and if possible implementing DSA for long context.…
Jul 2026 · github.com · its alternatives →
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Powers faster, efficient reasoning for long-running agents
Jun 2026 · developer.nvidia.com · its alternatives →
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GPT-6 Sol & Luna▲350Frontier AI intelligence, now at half the price
Sep 2026 · openai.com · its alternatives →
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A lightweight, single-binary coding agent harness written in Go. Anthropic, OpenAI, Kimi, DeepSeek, Google Gemini, Ollama, managed llama.cpp models, five built-in tools, three run modes, extensions in any language, and a built-in Telegram bridge.
May 2026 · zot.sh · its alternatives →
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Same model. Similar pass rates. 17.5x cost differences across 12 harness configurations.
Sep 2026 · frontierharness.org · its alternatives →
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DeepSeek Harness▲169Composable agent harness where everything is a plugin
Aug 2026 · github.com · its alternatives →
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Hey HN, We got tired of browser frameworks restricting the LLM, so we removed the framework and gave the LLM maximum freedom to do whatever it's trained on. We gave the harness the ability to self correct and add new tools if the LLM wants (is pre-trained on) that. Our Browser Use library is tens of thousands of lines of deterministic heuristics wrapping Chrome (CDP websocket). Element extractors, click helpers, target managemenet (SUPER painful), watchdogs (crash handling, file downloads, alerts), cross origin iframes (if you want to click on an element you have to switch the target first,…
Apr 2026 · github.com · its alternatives →
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Hey Hacker News! Launching gptengineer.app into beta today. It's like Claude Artifacts, but: - you can edit the code in your fav IDE (two-way github sync) - installs npm packages - automatically picks up build and runtime errors and fixes them - very fast, built with rust The full stack capabilities are built on supabase (prefer to not have to handle auth + user data at this point so this is owned by the user) The seed for this project was an open source experiment, posted about that previously here: https://news.ycombinator.com/item?id=36422730 Would love feedback if you give…
2024 · gptengineer.app · its alternatives →
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MiniMax M2.5▲194The first open model to beat Sonnet made for productivity
Feb 2026 · minimax.io · its alternatives →
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Viberia▲146Hey HN, This is my take on the agent harness. Everything on an isometric map. Agents are grouped into "buildings" that run in a sequence or a loop; e.g., the CodeForge has an agent that writes a PRD, another one that implements, and a third that reviews. Everything is customizable, you build your own buildings/teams however you want. It's a Tauri app, really light (about 8x less energy than the closest competitor I benchmarked, so it actually runs from a coffee shop on battery). It's macOS only for now, but ping me if you are willing to test the Windows or Linux version. I've been…
May 2026 · getviberia.com · its alternatives →
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Hey HN! Wanted to show our open source agent harness called Gambit. If you’re not familiar, agent harnesses are sort of like an operating system for an agent... they handle tool calling, planning, context window management, and don’t require as much developer orchestration. Normally you might see an agent orchestration framework pipeline like: compute -> compute -> compute -> LLM -> compute -> compute -> LLM we invert this so with an agent harness, it’s more like: LLM -> LLM -> LLM -> compute -> LLM -> LLM -> compute -> LLM Essentially you describe each agent in either a self contained…
Jan 2026 · github.com · its alternatives →
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Hi I'm Dan from Elodin, making an open source real-time capable flight software simulation. For AI Grand Prix contestants, the wait for the Round 1 virtual qualifier simulation has been grueling. If you’re competing, check out our simulation harness to tide you over, built to match the published competition constraints and message format. It runs against real Betaflight, which we learned requires at least 1000 sensor samples per second to run real-time correctly. The competition warranted introducing a new feature to generate the camera sensor directly in the simulation loop. Typically…
May 2026 · elodin.systems · its alternatives →
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Axis One▲78I’ve been building a small hardware box that runs local LLMs like Mistral, Qwen and Llama, and exposes an OpenAI compatible API on your local network. There’s no cloud, no login system and no telemetry. I built it because a lot of small firms want ChatGPTbstyle tools but can’t use cloud AI for privacy or compliance reasons, and most don’t want to deal with GPU servers, drivers, Docker or model configs. The aim is to make local AI feel as simple as plugging in a router. Right now the box boots into a very simple web UI where you choose a model and start using it. The API follows the OpenAI…
Nov 2025 · axis-one-psi.vercel.app · its alternatives →
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Agent Browser▲149I've built a browser agent harness that outperforms Browser Code on their own benchmark (BU Bench v1), on success rate, speed and cost. Browser Agent: 88% success rate, $5.37, 32,694 seconds Browser Code: 78% success rate, $8.34, 47,970 seconds For browser agents to become ubiquitous, they need to be faster, cheaper, and more reliable. The harness was built with token efficiency in mind (and uses 91% fewer tokens than Browser Code) to reduce the compute and VRAM budget necessary to fine tune a small, specialised model. Because browser agent inference is intermittent, a small specialised…
Mar 2026 · github.com · its alternatives →
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Hey HN! We are building HarnessRouter, a canonical API for running Codex, Claude Code, Hermes, and other managed agent harnesses as your product backend. Before building HarnessRouter, I used to build our own agent harness for our products. I tried LangGraph, agent SDKs from different vendors, pydantic, LLM tool use / function call, and so on. It's a very heavy lifting engineering effort, and I am disappointed about the agent deliveries compared to what Codex, CC can deliver. That changed my mindset. The frontier labs and famous open source communities are already putting so much…
Aug 2026 · github.com · its alternatives →
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A collection of open-source TypeScript tools by @enmanuelmag. heimdall-mcp for MCP proxy telemetry. agent-harness-kit for multi-agent orchestration.
May 2026 · ahk.cardor.dev · its alternatives →
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Qwen-3.7 Max▲10Cross harness foundation model for long running tasks
May 2026 · qwen.ai · its alternatives →
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2023 · samueltate.com · its alternatives →
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Hey HN. I built an AI agent harness over the past few months and I'm open sourcing it today. Some context on why. I've been building with Claude Code daily using this harness. It orchestrates multiple AI agents as a team, with a dashboard, chat, kanban board, the works. I used it to build a full SaaS product (MyUpMonitor, https://myupmonitor.com) in about 24 hours of focused coding. Then yesterday Anthropic announced Mythos and decided to keep it behind closed doors. Meanwhile I'm paying for Claude and I can't access their best model. I don't think that is nice at all... So I'm…
Apr 2026 · github.com · its alternatives →
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Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →