boeckeler-2026-maintainability-sensors · post

Maintainability sensors for coding agents

Created: 2026 · Ingested: 2026-09-11

https://martinfowler.com/articles/sensors-for-coding-agents.html

Maintainability sensors for coding agents recent article about harness engineering for coding agent users , I laid out a mental model for expanding a coding agent harness: a system of guides and sensors that increase the probability of good agent outputs and enable self-correction before issues reach human eyes. This article is a more practical follow-up where I walk through my experience with using sensors that help keep the codebase maintainable.

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supportsIn an agent's verify-and-fix loop, deterministic checks — tests, linters, schema validators — should be exhausted before any model-based judge is added, because they are free, fast and give the same verdict every time, while an LLM-as-judge costs tokens per run, returns non-deterministic verdicts, and so belongs only on properties no rule can express, and even then as an advisory signal until measured against human review.