Research

The Data Flywheel: Synthetic Data for Self-Improving Agents

Alex Thompson||6 min
+T

Training an AI agent feels like trying to teach a driver without letting them on the road. You get feedback, but you lack the messy, real-world edge cases that make systems robust. The bottleneck isn't compute. It's data: high-quality, diverse, and representative of the tasks agents will actually face.

The agent data gap

Autonomous agents need interaction trajectories: sequences of clicks, navigation steps, tool calls, and outcomes. Public websites and open datasets rarely expose this granularity. In many benchmarks, models perform well on a handful of scripted tasks but crash on realistic complexity. One recent evaluation of computer use agents showed a 30 to 50 percent performance drop when moving from curated test suites to open-ended web tasks. That gap is where synthetic data helps.

Synthetic data closes the loop

A data flywheel works when better data leads to better models, and better models produce better outputs that become new training signals. Synthetic data accelerates every stage. You can generate task variants, simulate edge cases, and create realistic outcomes. Training on this synthetic data improves model accuracy and behavior. When you re-evaluate on real-world tasks, you collect more edge cases. Those become new synthetic samples. The cycle repeats, with each iteration moving the agent closer to reliable performance.

Techniques that move the needle

  • Task decomposition: break complex workflows into smaller subtasks and sample variants at each step.
  • Outcome diversity: programmatically generate success, failure, and edge cases to teach robustness.
  • Tool emulation: simulate API calls and system messages to train tool use without real infrastructure.
  • Human-in-the-loop refinement: start with synthetic trajectories, let humans correct errors, and use those corrections to generate higher-quality synthetic data.

The flywheel works only if the synthetic data is realistic. Low-fidelity simulations can reinforce biases and create brittle behavior. High-fidelity synthetic data must mirror the structure, timing, and error modes of real interactions.

How Coasty fits

Coasty runs computer use agents on real desktops and browsers, capturing realistic interaction data and trajectories. It can produce synthetic datasets tailored to specific tasks, domains, or evaluation needs. This is not a self-serve product. Coasty offers a custom synthetic data service that you discuss directly with the team to match your use case.

A self-improving agent needs a data flywheel that keeps feeding it high-quality signals. Synthetic data is the fuel. To explore how Coasty can build custom synthetic datasets for your agents, book a data call with the Coasty data team at https://cal.com/coasty/coasty-data-call.

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