A second reader, and the 250 characters that silently disable it

This repo reviews itself, which is fine until the reviewer goes quiet. On 2026-08-25 the in-repo reviewer agent returned no report five times in a row, and the author ended up reviewing their own diffs. CodeRabbit is an advisory second reader: never a required check, never blocking, just another pair of eyes that is not the person who wrote the change.

The trap worth knowing before you edit the config

tone_instructions has a hard limit of 250 characters. Go over and CodeRabbit rejects the entire file, silently from our side: reviews still arrive, but on default settings, so every rule in the config stops applying. Platform shipped a 342-character value and its first day of reviews ignored the policy completely.

count it before you commit it

Whitespace is collapsed before counting, which is why a folded YAML scalar measures shorter than it looks.

The counting command itself was wrong

Platform's config carries a one-liner that splits the raw file on the literal tone_instructions: >-. That string also appears inside the comment documenting the command, so it measures the comment rather than the value. Run against this repo's config it returned 13 for a value that is really 221.

A checker that reports 13 out of 250 will never warn you, whatever you write. Parse the YAML instead of splitting the text.

What it is told to look for here

The path instructions are written from defects this repo has actually shipped, not from generic advice.

path	top defect class

Generated surfaces are excluded: plugins/, src/hooks/dist/, the Lab output and PR playground dirs. Reviewing a build artifact produces findings against code nobody edits by hand.