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Sweep 22 Oct 2026 · 04:32Z Build v2.1.308 527 read Stable v2.1.308 Latest v2.1.308 Next v2.1.308 Feeds RSS JSON llms.txt llms-full.txt Unofficial

Claude Code v2.1.199 ·

Credential Masking: Regex Extract Patterns

Entry
JSON All of v2.1.199
EntryKind: in v2.1.199,
ImprovementsSection of the release

The credentials.files sandbox setting now supports extracting and masking only specific values from a file rather than masking the entire file contents.

Details
  • New extract field: a regex with a capture group 1 that identifies the credential value(s) within the file; the proxy substitutes only those captured values
  • New onExtractNoMatch option controls what happens when the pattern matches nothing:
  • "warn" (default) — logs a warning and leaves the file unprotected
  • "deny" — degrades to full-file deny mode (file is blocked from sandbox)
  • "error" — throws at initialization, preventing session start with a misconfigured entry
  • New maskDuplicates option: also masks occurrences of extracted values found elsewhere in the file outside the capture groups

Example config:

{
  "credentials": {
    "files": [{
      "path": "~/.config/tool/credentials",
      "mode": "mask",
      "extract": "token=([A-Za-z0-9_-]+)",
      "onExtractNoMatch": "deny",
      "maskDuplicates": true
    }]
  }
}
Evidence

(search for "onExtractNoMatch", "extract pattern", "maskDuplicates")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.199 →

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