Skill issue: Lessons from skilling up coding agents to use Langfuse - Marc Klingen, Clickhouse
May 20, 2026 · 24:09
Marc Klingen, founder of Langfuse, shares six learnings from building a skill that lets coding agents like Claude Code add Langfuse observability and evals to projects. The skill addresses the problem of agents hallucinating stale instrumentation from outdated pre-training context by surfacing a search endpoint for documentation, helping agents navigate 478 documentation pages, and referencing rather than duplicating content. Klingen explains how examining traces revealed 80% of issues, basic eval setups were better than none, and an auto-research loop with a target function suggested six improvements (three accepted). However, the target function nearly backfired by optimizing away documentation-fetching steps vital for long-term reliability. He also discusses challenges of skill distribution, versioning, and whether to aim for quick initial setup or perfect single-shot implementation.
