Evaluating AI Agent Skills

Langfuse utilized datasets, tracing, and the Claude Agent SDK to enhance an AI agent skill designed for accessing Langfuse's API, documentation, and observability practices. By treating skill evaluation like prompt evaluation, they stored user prompts in datasets and traced agent behaviors, iteratively improving the skill's quality. Initial challenges included the agent's frequent CLI errors, unnecessary retries, and incorrect usage of commands, which were addressed by enforcing mandatory parameters and adding proactive discovery steps. A restructuring of the skill's description initially led to its non-invocation, prompting a return to a more detailed explanation. Evaluating complex tasks like application instrumentation required using an LLM as a judge to verify the agent's modifications. Through detailed trace reviews and iterative adjustments, Langfuse identified areas for further enhancement, such as reducing CLI calls and refining auto-instrumentation in complex cases, with ongoing improvements and best practice documentation planned for the future.