Shuriken vs Agentastic (2026)

We make Shuriken. We tried to be fair; corrections welcome at office@shuriken.sh.

Quick answer#

Agentastic is a strong pick if you work on a Mac (macOS 14 Sonoma or later) and want a free, polished multi-agent IDE with cloud sandboxes on Modal, Fly or Vercel and long-running manager agents. Shuriken fits if you need a desktop app on Windows or Linux, run several Claude or ChatGPT accounts and want chats to move between them at the limit, or want one MCP sign-in that works on every device.

Much is the same. Both put each agent in its own git worktree. Both have a built-in browser where you click an element and send it to the agent: Agentastic calls it Design Mode, Shuriken calls the button Design. Both reach your phone, Agentastic through an iPhone app in TestFlight and Shuriken through the web app at app.shuriken.sh. They differ on where agents can run (Agentastic has managed sandboxes, Shuriken doesn't), on accounts (Shuriken pools them), and on Windows and Linux, where only Shuriken has a desktop app.

At a glance#

Agentastic's column comes from its home page and FAQ, read on 22 October 2026.

What Agentastic does well#

Free, with no sign-up. That's the headline on its FAQ, and it's a generous one. You bring your own agent subscriptions or API keys and pay the vendors directly. An Agentastic account is only needed for its relay and sharing features.

Design Mode. Click any element in a real Chromium window and its HTML, CSS and a cropped screenshot go into the agent's prompt. It's one of the best ideas in this category, and we liked it enough to build our own take (more below).

Cloud and remote targets. Agents can run on any dev server over SSH, or on Modal, Fly and Vercel Sandbox, and sessions keep going after your Mac sleeps. If you'd rather not keep your own machines awake, that's a real advantage.

Container isolation. Besides worktrees, Agentastic can isolate work in Docker or Apple containers. That's stronger isolation than a worktree alone gives you.

Manager Agents. Long-horizon agents that turn a metric or spec into objectives and steer worker agents over days. Shuriken doesn't do this. It's a harness: it runs your agents and keeps them going, and our own experiments in that direction aren't ready (what a harness is).

A native Mac app. If you live on macOS and like apps that feel like macOS, Agentastic is built for you.

Where Shuriken is different#

Windows and Linux are first-class#

Agentastic's desktop app needs macOS 14 or later; on Windows you get its CLI through WSL. Shuriken's desktop app runs natively on Windows 10 and 11 (x64) and on Linux as an AppImage or .deb, on x64 and Arm. You can also add a headless Shuriken server on Linux, macOS or Windows from the app, and it installs and checks the agent CLIs for you.

If your team is half Mac, half Windows, or your best machine is a Linux box under the desk, that matters more than any feature row.

Your accounts work as a pool#

This is the reason Shuriken exists. You add every subscription sign-in and API key you own as a source: several Claude accounts, ChatGPT for Codex, Gemini, Copilot and more. When the one in use reaches your switch point (99% by default, adjustable from 50% to 100%) or the provider reports a limit, your chats move to the source with the most room. A Claude Code chat moves on its next request, subagents included; other agents move when their turn ends. API keys can be a last resort, if you turn that on (it's off by default): they take over only once every subscription is out, and a spend cap per fallback run ($25 by default, across every key the run uses) stops them there.

On top of that, session limits start an idle Claude account's 5-hour window with one tiny background request, once per window, so its limit comes back early. Your chats stay where they are. See source switching and session limits.

We didn't find anything like this on agentastic.dev. Only use accounts you own and are entitled to use; providers' terms may not allow sharing a subscription sign-in.

MCP sign-ins once, everywhere#

Agentastic's plugins follow an agent to SSH hosts and containers, which is neat. Shuriken's angle is different: you keep one list of MCP servers for every project, assign each to all projects or chosen ones, and sign in once. The sign-in belongs to the server, not to your AI account, so switching accounts or devices never asks again, and it travels sealed between your devices. There are 57 ready-made connectors, from GitHub and Linear to Sentry and Figma. See Global MCPs.

Design mode: point at the page#

Shuriken's built-in browser shows your running app beside the chat. Press Design and the strip under it says "Click the part of the page you want to change. Shift-click for several." Then type the change and press Send; Esc picks another element. The agent gets each element's details and a cropped screenshot. Shuriken 5.1 added two things. Dictate a note lets you say the change instead of typing it, and while the agent is busy, Send becomes Queue message. Agents drive the same tab you see, and password fields never leave the page. The walkthrough is in point at the page, and the browser page has the rest.

Voice works everywhere else too: your speech is turned into text on your own computer by NVIDIA Parakeet by default (or live by ElevenLabs, AssemblyAI or another provider on your own key), and you can paste text mid-sentence to have it land where you were.

Your phone, Android included#

Agentastic's iPhone app is in TestFlight. Shuriken's phone option today is the web app at app.shuriken.sh, on any phone browser, installable to the home screen: every chat, the queue, Changes and voice. Native iOS and Android apps are planned for November 2026.

What you give up#

Shuriken has no managed cloud sandboxes and no Docker or Apple container isolation. Agents run on machines you own, one worktree per chat. We chose that because it keeps your code and chats on your hardware, with our cloud relaying only sealed messages. The cost is that a Mac, PC or server of yours has to be switched on. Shuriken also isn't free without limits: Free stops at two sources and two linked devices, and a third of either needs Pro.

Pricing#

Agentastic is free. Its FAQ says: "Free without limits. No sign-up required. No strings attached. We don't charge for the agents." You pay Anthropic, OpenAI or Google for the agents themselves.

Shuriken prices are in euros, VAT included for EU consumers. Free is €0 with no card: two sources, two linked devices, every agent, switching, session limits, global MCPs, the browser with Design mode, voice and the phone web app. Pro is €49 a month or €490 a year (2 months free) and removes the source and device limits. Details on pricing.

Shuriken never bills model usage either. Your agents run on your own plans and keys.

Which should you choose?#

• Mac only, want cloud sandboxes or manager agents, want it free: Agentastic.
• Windows or Linux, or a mix: Shuriken.
• Several Claude or ChatGPT accounts and tired of logging in and out: Shuriken.
• Want to follow agents from an Android phone today: Shuriken's web app.

If you're weighing other Mac apps too, our Shuriken vs Superset page covers the closest feature twin. To try Shuriken on your own machines, download it here.