mathiasandClaude Sonnet 5
42578c21b9
Round-6 review found a bypass in a different mechanism than rounds 1-6's fence-detection family: frontmatterScalars's indentation guard skips any indented continuation line outright, so old_str="half_life: durable", new_str="half_life:\n garbage-value" turns the field into a YAML block-scalar shape whose real value lives on the continuation line. present()'s own "empty value = placeholder, not an assertion" contract then treats the field as absent, and claim.ValidateEnvelope never sees the invalid value at all — no encoding quirk needed, one ordinary brain_edit call smuggles an out-of-enum value straight past the check. Fold indented continuation lines into the value when a top-level key's inline value is empty, so oneOf() still sees what was actually written. A genuinely empty value (no indented line follows) still folds to "", preserving the existing placeholder-not-assertion behavior for legitimately unset fields. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>