Research

The Data Flywheel: Synthetic Data for Self-Improving Agents

David Park||6 min
+T

Training and evaluating autonomous agents usually hits a wall. Real desktop and browser interactions are rare, costly, or sensitive. You get a small slice of labeled data and then the model stagnates. The problem isn’t model capacity; it’s the data flywheel. You need more interaction data, faster iteration, and higher quality trajectories to push agents forward. Synthetic data closes that loop.

Real agents need real interaction data

Autonomous agents that click, type, and navigate applications need more than text prompts. They need trajectories that capture mouse movements, keyboard sequences, and the visual context of each step. Current benchmarks rely on a handful of manually scripted tasks. For example, recent agent benchmarks use under 50 distinct workflows. That is not enough to learn robust strategies across tools, UIs, and edge cases.

Synthetic trajectories scale without real users

You can generate thousands of realistic trajectories by simulating computer use. An agent that logs into a CRM, updates a deal, and closes a ticket can be replayed millions of times with slight variations in inputs. You get labeled interaction data that covers edge cases and rare workflows without risking production systems. Teams using synthetic trajectories report a 3x increase in test coverage and a 40% reduction in manual labeling effort compared to traditional crowdsourced approaches. That scale enables you to evaluate agents against a broader distribution of tasks and surface behaviors that would never appear in a real-world log.

Evaluation loops accelerate model improvement

The data flywheel only works when you evaluate agents and feed results back into the next generation of synthetic data. You run a baseline agent on a synthetic test suite, measure success rates and failure modes, then generate new trajectories that specifically address those failures. For example, if an agent frequently gets stuck on multi-step forms, you produce synthetic scenarios that teach it to recognize form fields and handle errors. This iterative process can cut model iteration time in half because you stop guessing what data you need and instead generate exactly what your agent struggles with.

Practical tradeoffs to watch

Simulation fidelity matters. Low-fidelity mocks lead to agents that fail when they encounter real UIs. High-fidelity environments maintain layout, interaction patterns, and error states.Labeling quality is still important. Synthetic trajectories must be labeled with correct outcomes, not just clicks. Human review or automated verification is required.Data diversity drives robustness. Over-simulating the same workflows creates bias. You need a mix of common and rare tasks to cover the real distribution.

The data flywheel turns a static dataset into a live training and evaluation engine. You generate synthetic trajectories, evaluate agents, identify gaps, and feed those gaps back into the next round of data. That loop is what takes agents from basic demos to production-ready systems.

How Coasty fits

Coasty runs computer use agents on real desktops and browsers to capture realistic interaction data. This enables the creation of custom synthetic datasets and trajectories tailored to your workflows, tools, and edge cases. The service is custom-built and contact-led, meaning you work directly with the team to design the scope, data format, and integration points that match your project. There is no self-serve product or fixed package. You talk to the Coasty data team, define your requirements, and get a solution that fits your needs.

If you are building or evaluating autonomous agents, you need a continuous supply of high-quality interaction data. Book a data call with the Coasty team to explore how synthetic trajectories and data flywheel strategies can accelerate your agent development at https://cal.com/coasty/coasty-data-call.

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