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Guide

Daniel Kim6 min
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You cannot trust an AI agent on production without seeing how it behaves on the weird, the broken, and the dangerous. Real user interactions are rare, expensive, and often guarded by privacy and security rules. Companies need more test data, not less. Synthetic data solves the problem by generating thousands of realistic scenarios on demand.

The Real Bottleneck in Agent Testing

Most teams suffer from stalled agent evaluations because they lack diverse, realistic scenarios. A study of 50 agent-focused projects found that 68% had fewer than 1,000 labeled test cases, and 82% reported that real-world edge cases were missing. That means you are mostly testing the happy path while the agent might fail on typos, unexpected UI states, or malicious inputs. Without enough scenarios, you cannot catch regressions, security issues, or usability problems before launch.

How Synthetic Data Improves Red Teaming

Synthetic data lets you artificially inflate the number of edge cases without touching real users. You can inject malformed URLs, weirdly formatted forms, rapid-fire prompts, or simulated phishing attempts to see how an agent responds. One technical blog reported that a synthetic red teaming suite increased the number of discovered vulnerabilities by 4.2x compared with manual testing alone. Synthetic data also makes it easy to enforce consistency: every run gets the same set of adversarial cases, so you can compare model versions and track regression over time.

Key Tradeoffs to Watch

  • Model fidelity: Synthetic scenarios must closely mimic real environments. If the simulated UI or browser behavior is off, the agent might pass a test but still fail in production.
  • Coverage vs. realism: You can generate thousands of edge cases quickly, but some rare interactions are hard to capture without real usage data.
  • Bias amplification: If your generation logic reflects existing data biases, the synthetic red team will reinforce those issues rather than surface them.
  • Maintenance overhead: You need to keep the synthetic scenarios aligned with real product changes, otherwise you risk testing outdated workflows.

High-quality synthetic test data lets you scale red teaming, uncover edge cases, and compare agent versions consistently. The main risk is relying on simulations that do not reflect the actual user environment.

How Coasty Fits

Coasty runs computer use agents on real desktops and browsers. By observing these agents, Coasty can capture realistic interaction data and turn it into synthetic datasets and trajectories. That means its synthetic scenarios are grounded in actual UI and web behavior, not just scripts. Coasty offers a custom synthetic data service tailored to your workflows, evaluation needs, and security constraints. It is a contact-led engagement, so you work directly with the team to define requirements, scopes, and outputs.

If you want a synthetic data approach that reflects real user environments, book a data call with the Coasty data team at https://cal.com/coasty/coasty-data-call.

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