HarnessRouter

Handling cost control at the agent level is tricky—does HarnessRouter allow setting strict token/cost caps per request or per user?

The agent-session model is what I'd want to understand before building on top of this. When Claude Code or Codex stops mid-task to wait on a tool call or user permission, does HarnessRouter maintain the in-flight state for that run, or does the app need to handle the resume logic itself? Curious how recovery actually looks when a long-running agent crosses a timeout or drops a connection.

one api across agents is a nice pitch but it also means you're now the single point of failure for every app that plugs in. if HarnessRouter itself has an outage or a rate-limit issue on your end, does traffic fail over to hitting the underlying provider directly, or does the whole integration just go down with you? curious how much of the reliability story is actually in your hands vs still tied to whichever agent is behind the call that day.

Huge congratulations to the team! The orchestration and sandbox management headache is real, so this feels super timely.

Love the infrastructure angle.Curious—do you think the long-term moat is access to many models, or helping developers choose the right one automatically?

Congrats on the launch @renchu_song - I've actually been looking for a product like this for months. Glad someone has finally done it. Looking forward to trying it out!

Congrats on the launch Richard!

the eval-suite-gates-the-switch answer to Brandon above is a genuinely satisfying answer, more concrete than most vendor-lock-in claims I see here. question on that - are those eval suites something your team builds and maintains centrally per vertical, or can a customer plug in their own rubric and test cases for their specific use case before they trust a harness swap in production?

@renchu_song Epic launch! One question I had while looking through it: what is the most common mistake teams make when they try to build multi-agent infrastructure on their own before using something like HarnessRouter?

One API across agents solves the problem every team hits by month three, getting locked into a single vendor's agent right when a better one ships. Smart wedge. The place this gets sticky is evals and observability. Whoever owns routing is best positioned to tell me which agent wins for which task, and per-task performance data turns you from a router into the layer teams cannot rip out.

@renchu_song Congratulations!

neat landing page and easy to understand explanation. tho, one question comes to mind: Since different harnesses output varying artifact formats, how does HarnessRouter enforce a consistent schema when returning structured results back to the host app?

Not being locked into one harness is the claim I'd want to poke at, since swapping Claude Code for Codex with one line of config sounds simple, but different harnesses often disagree in how they interpret the same instructions, how they handle tool permissions, and what kind of output they naturally produce. If someone builds their AGENTS.md and their whole prompting approach tuned around Claude Code's habits, does switching the config line actually give equivalent results with Codex, or does it quietly need a rewrite of the instructions to get the same quality out of a different underlying agent.

Also, on the healthcare compliance use case specifically, running sandboxed agents against real operational and patient adjacent data raises the obvious question of where that data physically lives during a run and after it finishes. Is anything retained on your infrastructure once a task completes, or does everything get destroyed with the sandbox, since that is usually the first thing a healthcare compliance team will ask before they trust a third party backend with their data.

Hey Product Hunters,We're the HarnessRouter team. Building an AI agent backend yourself takes months: a sandbox per run, agent runtime, tool orchestration, files and artifacts, sessions and streaming, retries and timeouts, permissions, cost controls. And the upgrades, fixes, and maintenance never stop.So we built HarnessRouter: bring the world's best AI agents into your app, with one API. Codex, Claude Code, Hermes, and more, running as your product's backend.Here's what people are already building with HarnessRouter as their backend:🎬 A cutting-edge AI video marketing startup uses HarnessRouter to drive their content generation loop, producing human-level viral video content. 🏥 A top medical research institution uses HarnessRouter to build an academic brain that connects all their operational data into a unified agent plane. ✅ A leading healthcare compliance company uses HarnessRouter to bake human domain expertise into agent skills, saving their customers hundreds of hours of labor.What HarnessRouter does: your app sends a task through one API, HarnessRouter runs it using Codex, Claude Code, Hermes, and soon more, then sends back finished work: code, files, videos, games.How you use it：1. Drop our AGENTS.md into Cursor or Claude Code2. Describe your idea, for example: "Build a founder launch-video app: users drop a logo and an idea, get a launch video."3. Add your API key. Ship.What happens behind the scenes: each task runs inside its own sandbox, traced step by step, so you can see exactly what the agent did. What comes back is structured and renderable, not just a chat reply: reviewable diffs, generated files, images, confirmations of real tool actions. And you're not locked into one harness. Claude Code today, Codex tomorrow, swappable with one line of config, and flexible enough to run thousands of harnesses concurrently.Free during a 7-day trial. Would love for you to try it and tell us what your app should build. Reading every comment today. 🙏