You added a rule to CLAUDE.md and Claude is not following it. What should you check first?

The principle — check whether the instruction arrived, and whether something else is arguing with it, before you rewrite it.

Why the key is correct — two facts drive the diagnosis. Anthropic states that if two rules contradict each other, Claude may pick one arbitrarily, so a conflicting instruction elsewhere produces exactly this symptom. And discovered memory files are concatenated into context rather than overriding each other, which means a nested file does not replace a parent — it adds to it, and both can be in play at once. Confirming what actually loaded, and then looking for a contradiction across those files, resolves most cases of this.

Why the others are wrong — reporting it as a defect misreads the mechanism, because CLAUDE.md is context rather than enforced configuration and perfect compliance was never the contract. File size does matter but in the opposite direction, since longer files reduce adherence. And rephrasing more forcefully is the instinct that produces shouty instruction files without improving anything; specificity and consistency are what move the needle.

Remember this — when a rule must hold regardless of what Claude decides, stop editing the instruction file and use the enforcement layer instead.

Sources — Anthropic's memory page.