You want a computer use agent that works like a human on real desktops, browsers, and terminals. The Coasty Computer Use API lets you pick the model that fits your budget and control needs. v3 is a simple, deterministic model. v4 is an autonomous model with a built-in pass/fail verifier. Both run the same OSWorld benchmark, but they behave differently in production.
How it works
You start a task run with POST /v1/runs. The model receives your task, a machine_id, and a cua_version. cua_version can be "v3" or "v4". v3 follows your instructions step by step. v4 is autonomous with a pass/fail verifier. The agent captures screenshots, predicts actions, and executes them until the status is "done" or a failure occurs. v4 also has a pass/fail verifier that evaluates the final result. You can stream events with GET /v1/runs/{id}/events to track progress in real time.
curl -X POST https://coasty.ai/v1/runs \
-H "X-API-Key: $COASTY_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"machine_id": "your_machine_id",
"task": "Open https://example.com and print the title",
"cua_version": "v4"
}'v3 vs v4
- v3 is a deterministic model for controlled tasks. You control every step. It is cheaper per step.
- v4 is autonomous with a pass/fail verifier. It can decide when to stop. It charges $0.05 per agent step, same as v3.
- Both use the same OSWorld benchmark and return actions + status. v4 adds a pass/fail verifier.
- v4 is ideal for complex workflows where you want the agent to self-correct and evaluate the final result.
- v3 is ideal for simple, repeatable tasks where you want full control and predictability.
Choose v3 for controlled, cheap tasks. Choose v4 for autonomous agents with a built-in pass/fail verifier.
Where this beats brittle automation
Traditional automation relies on brittle selectors, XPath, or hard-coded IDs. A UI change breaks everything. The Coasty computer use agent sees the screen like a human does. It works across browsers, desktop apps, and terminals. It adapts to layout changes and dynamic content. You get reliable automation without maintaining complex selectors for every task.
Pick the model that matches your control and verification needs. v3 gives you deterministic control. v4 gives you autonomy with a pass/fail verifier. Build robust computer use agents and workflows. Get your key at https://coasty.ai/developers.
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