Resolution, reasoning only, nothing executed. The evasion is a layer mismatch: a text regex expecting one backslash is applied to serialized JSON where each backslash is doubled and may be a unicode escape, so the serialized bytes never contain the shape the author had in mind. Patching the regex for the doubled form leaves unicode escapes, percent encoding and nested serialization open. The fix is to parse first, walk the decoded tree with an explicit worklist, apply rules to every decoded string value including object keys, and emit only a canonical re-serialization of the validated tree so the checked value and the sent value are the same bytes. Before matching, build a match-only normalized copy: fold fullwidth and lookalike separators, treat forward and back slashes as one separator class, apply a fixed named set of decoders (percent, unicode escape, nested document) for a bounded number of rounds until no decoder changes the string, and treat any stripped prefix such as a share, file scheme or home shorthand as a match by itself. Score per whitespace token so a path embedded mid sentence still trips. Rejection records must be incapable of carrying the value: a schema-derived field pointer, a rule id from a closed enumeration, a coarse length bucket and a keyed hash under a rotating secret that is never logged; drop parser and matcher error text entirely and map it to local codes. Start the verdict at deny and withhold the whole document on any abort. This matches the three existing skills found at task start; no new reusable guidance beyond them emerged, and an attempted executed check of the regex mismatch was not run because scratch file creation was declined, so the finding remains unverified by execution.

Design question about an outbound privacy filter. The filter scans JSON payloads for strings that look like identifying filesystem paths and blocks them. A regex written for ordinary text misses Windows paths once they are JSON encoded, because each backslash becomes a doubled backslash and other characters may be unicode escaped, so the serialized bytes no longer match the pattern. The question is how to structure validation so it operates on decoded string values rather than on the serialized document, how to normalize the many equivalent encodings of a path before matching, and how to report a rejection without writing the rejected value into logs or error messages. Known evidence: the evasion is a mismatch between the encoding layer the regex was written for and the layer it is applied at. Unknowns: best normalization steps, how to handle nested and double encoded values, and what a safe rejection record should contain.