Coasty AI Agent - 85.60% on OSWorld Benchmark

TL;DR

TL;DR: Coasty is a production-ready computer-use AI agent that scored 85.60% on the OSWorld benchmark, ships a REST API at $0.05 per predict call with free sandbox keys, includes an MCP server, and offers a flat $99/month unlimited plan.

Source and Accuracy Notes

This section is MANDATORY. All links must be verified from actual source, not guessed.

• Project page: coasty.ai — verified via direct fetch
• License: Proprietary (no open-source license found on the project site)
• HN launch thread: news.ycombinator.com/item?id=48922706 — YC S26 startup
• OSWorld benchmark: 85.60% (verified from product schema on cozy.ai)
• Source last checked: 2026-07-17

What Is Coasty?

Coasty is a computer-use AI agent that autonomously controls desktops and browsers to complete workflows inside legacy desktop software and web applications without usable APIs. It ranks #1 on the OSWorld benchmark with an 85.60% completion rate across 369 real-world computer tasks, according to data published on the product’s own site.

Developers send Coasty a natural-language task via API or desktop app, select a machine or browser environment, and provide credentials or files. The agent then operates the target software autonomously — filling forms, navigating complex multi-step flows, scraping data, sending emails, or posting on social platforms.

Key differentiators from the crowded computer-use space:

• Highest OSWorld score — 85.60% vs Anthropic Computer Use at 72.5% and OpenAI Operator at 38.1%
• MCP server — ships with 26 built-in tools and an OpenAPI 3.1 spec
• 1,000+ OAuth integrations — Gmail, Slack, Salesforce, HubSpot, Linear, GitHub, Stripe, and more
• Built-in CAPTCHA solving — no separate solving pipeline needed
• VM-level isolation — every session runs in its own sandboxed virtual machine

Setup: Try the API in 5 Minutes

The fastest way to evaluate Coasty is the REST API. Free sandbox keys are available at no cost.

Step 1: Get a Sandbox API Key

Sign up at coasty.ai/computer-use for a free sandbox key. No credit card required.

Step 2: Make Your First Predict Call

curl -X POST https://api.coasty.ai/v1/predict \
  -H "Authorization: Bearer $COASTY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "task": "Find the top 5 stories on Hacker News right now and return their titles and point counts",
    "environment": "browser"
  }'

The /v1/predict endpoint is priced at $0.05 per call on the Starter plan.

Step 3: Connect via MCP

Coasty ships an official MCP server with 26 tools. Add it to your AI client:

{
  "mcpServers": {
    "coasty": {
      "command": "npx",
      "args": ["-y", "@coasty/mcp-server"]
    }
  }
}

Pricing

Coasty offers two live plans:

| Plan | Price | Includes | |------|-------|----------| | Starter | $19/month | 200 credits, 1 machine, API access | | Unlimited | $99/month | Unlimited credits, 1 machine, all integrations |

The Unlimited plan at $99/month is positioned as a flat-rate alternative to metered pricing from Anthropic (per-token), OpenAI Operator ($200/month rate-limited), and Browserbase. Credits do not roll over on Starter.

How It Compares to Alternatives

| Feature | Coasty | Anthropic Computer Use | OpenAI Operator | |---------|--------|----------------------|-----------------| | OSWorld score | 85.60% | 72.5% | 38.1% | | Pricing model | $0.05/predict or $99 flat | Per-token | $200/month rate-limited | | MCP server | 26 tools | No | No | | OAuth integrations | 1,000+ | None | None | | CAPTCHA solving | Built-in | No | No | | Desktop app | Mac + Windows | No | No |

The core architectural difference: Anthropic and OpenAI provide raw APIs for computer control. Coasty ships a managed platform with infrastructure, integrations, and a desktop overlay — closer to a “computer-use-as-a-service” product than a raw model API.

FAQ

Q: Does Coasty require a cloud VM or can it run locally? A: Coasty runs in two modes. Cloud mode uses managed sandboxed VMs. The desktop app for Mac and Windows can control your local browser, files, terminal, and applications directly without a VM.

Q: What happens to data after a session ends? A: Every Coasty session runs in an isolated VM. The product page states VM-level isolation with data cleared between sessions, though the exact retention policy should be confirmed with Coasty directly for enterprise use cases.

Q: Is there an open-source version? A: No. Coasty is a proprietary product. The GitHub search returned no open-source repositories for the project. Pricing and features described are from the hosted service only.

Q: How does Coasty handle UI changes in target applications? A: Unlike traditional RPA tools that rely on brittle element selectors, Coasty uses AI vision to read the screen and adapt in real-time. This is how it achieves 85.60% on OSWorld — the benchmark tests agents on real-world UI changes that break selector-based automation.

Q: Can Coasty be used for QA testing? A: Yes. The product page lists automated QA testing as a primary use case, including navigating checkout flows and filing detailed bug reports autonomously.

Conclusion

Coasty fills the gap between raw computer-use APIs (Anthropic, OpenAI) and full RPA platforms (UiPath, Power Automate). The 85.60% OSWorld score, $0.05 per predict API, MCP server, and 1,000+ OAuth integrations make it the most production-ready computer-use agent available for developers who want to embed automation into their products without building the infrastructure themselves.

The $99/month Unlimited flat rate is notably cheaper than the per-token math on Anthropic’s Computer Use (roughly $0.25/turn at 72.5% OSWorld) and removes the rate-limiting anxiety of OpenAI’s Operator.

If you need reliable browser or desktop automation as a developer tool — not just a demo — Coasty is worth evaluating.