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Claude Sonnet 5.5 (effort default (no --effort flag) · thinking on) on Scrub personal data and secrets from log lines before sharing (tokens, URL secrets, emails, IPv6/IPv4, Luhn-checked card numbers)

AClaude Sonnet 5.5default · thinking on · Claude Code 2.1.299 (headless -p) · cloud · 2026-10-20 · by @bobsiopener

Trust 80%Fully autonomoussuccess · first try
Estimated cost
$0.08
Wall time
24s
Human step-ins
0
Outcome
Pass

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Summary

Exact prompt

# Scrub personal data and secrets from logs before sharing them We share service logs in public bug reports, so `redact.py` must remove personal data and secrets first. The current regexes leak a lot and also mangle harmless text. Rewrite `redact(line) -> str` in `redact.py` (Python 3 stdlib only) to follow these rules **exactly, in this order**, each rule working on the output of the previous one. `sample.log` / `sample.expected.log` show 40 lines of correct input/output. "Word character" below means `A-Z a-z 0-9 _`. 1. **JWT.** `eyJ` followed by any run of `[A-Za-z0-9_-]`, then `.`, one or more `[A-Za-z0-9_-]`, `.`, one or more `[A-Za-z0-9_-]` -> `<JWT>`. The match must not be preceded or followed by a word character or `-`. 2. **Bearer.** The word `bearer` (any case, not preceded by a word character), then one or more spaces, then a run of non-space characters (the token). Keep the word and the spaces exactly as written; replace the token with `<TOKEN>`, except a token that is exactly `<JWT>` stays `<JWT>`. 3. **Secret URL parameters.** After `?` or `&`, a parameter named (any case) `token`, `access_token`, `api_key`, `apikey`, `key`, `secret`, `password`, `pwd` or `sig`, then `=`: its value (everything up to the next `&`, `#`, whitespace, `"`, `'` or end of line) becomes `<REDACTED>`. An empty value stays empty. Names not preceded by `?`/`&` are not parameters (`key=1` in plain text stays). 4. **Email.** Local part `[A-Za-z0-9._%+-]+` (not preceded by one of those characters), `@`, then dot-separated labels of `[A-Za-z0-9-]+` with at least two labels and a final label of 2+ letters only, not followed by `[A-Za-z0-9-]` -> `<EMAIL>`. (`a@b` and `@admin` stay.) 5. **IPv6.** Take each maximal run of the characters `0-9 A-F a-f : .`. If it contains at least two `:`, is not preceded or followed by a word character, and `ipaddress.IPv6Address(run)` accepts it, replace the whole run with `<IPV6>` (so `::ffff:1.2.3.4` is one `<IPV6>`; brackets and `:port` around it stay). Times like `12:30:45`, MAC addresses and `std::vector` stay. 6. **IPv4.** Take each maximal run of digits and dots of the form `digits(.digits)+`. Replace it with `<IPV4>` only if it has exactly 4 parts, each 0-255 with no leading zero (`0` itself is fine), it is not preceded by a word character or `.`, not followed by a word character, and not followed by `.` + digit. `:port` after it stays. `1.2.3.4.5`, `10.0.0.256`, `01.2.3.4` stay. 7. **Payment cards.** Take each maximal run of digits where neighbouring digits are separated by nothing, one space or one hyphen (pattern `\d([ -]?\d)*`). If it is not preceded or followed by a word character, has 13-19 digits in total and the digits pass the Luhn check, replace the whole run with `<CARD>`. Otherwise leave it unchanged (do not look for shorter sub-runs). Everything else in the line is kept byte for byte. ## Scoring Hidden check groups (partial credit = fraction passed; all must pass): `jwt_bearer` (1-2), `url_params` (3), `email` (4), `ipv6` (5), `ipv4` (6), `cards_luhn` (7), `rule_order` (interactions between rules), each with exact expected lines; then on a hidden 150-line log made like `sample.log`: `generated_accuracy` (at least **97%** of lines exactly equal to the correct output), `no_leaks` (on **every** line, each placeholder type appears at least as many times as in the correct output) and `no_overredaction` (**every** line that the rules leave unchanged is returned unchanged).

Seven ordered rules where order matters (JWT before Bearer, IPv6 before IPv4), with decoys (versions, MACs, times, std::vector, non-Luhn order ids). Stated thresholds: >= 97% exact lines on a hidden log, zero leaks and zero over-redaction. Original benchmark task written for usecaserank.com (not based on a specific public post). Headless, offline run on a reproducible fixture. Each run's notes say how its cost was measured (estimates are marked).

Success criteria: 1. jwt_bearer 2. url_params 3. email 4. ipv6 5. ipv4 6. cards_luhn 7. rule_order 8. generated_accuracy (>= 97% exact lines) 9. no_leaks (every line) 10. no_overredaction (every line)

Setup notes: Use Case Scout batch 8 case i03-log-pii-scrubber (offline fixture). Prepared with batch8/prepare.sh; hidden key/tests kept outside the agent's work dir. Prompt = TASK.md verbatim. Scored with the scout's scorer: `python score.py WORKDIR KEYDIR`. Tools: Read/Write/Edit/Glob/Grep/Bash, web disabled. Single run, no retries. Claude Code's own reported cost for claude-sonnet-5.5: $0.080364. Score: 10/10. Cost is an ESTIMATE: measured tokens x pricing.json list price (Claude Pro subscription, nothing billed); input_tokens include cache reads and writes. Single run.

Estimated cost List-price estimate; not actually billed.

Metrics

Estimated cost
$0.08
Wall time
24s
Human step-ins
0
Turns
3
Model usage
ModelInput tokOutput tokCost
AClaude Sonnet 5.5anthropic/claude-sonnet-5.5effort default (no --effort flag) · thinking on63,0743,196$0.08

Reproduce this run

  1. Use the use case prompt on the use case page.
  2. Same setup: Claude Sonnet 5.5 (anthropic/claude-sonnet-5.5, effort default (no --effort flag) · thinking on) via Claude Code 2.1.299 (headless -p), cloud.
  3. It counts as a success only if it meets every success criterion: 1. jwt_bearer 2. url_params 3. email 4. ipv6 5. ipv4 6. cards_luhn 7. rule_order 8. generated_accuracy (>= 97% exact lines) 9. no_leaks (every line) 10. no_overredaction (every line)
  4. Log model, tokens, wall time, human step-ins and the evidence log, then submit it as a reproduction. A different model? Submit a head-to-head rerun.

How runs are scored: Methodology.

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Automated checks

Trust 80% comes from these checks (how Trust % works).

Evidence log
[
 {
  "duration_api_ms": 23146,
  "stop_reason": "end_turn",
  "session_id": "[REDACTED]",
  "total_cost_usd": 0.0803637,
  "usage": {
   "input_tokens": 6,
   "cache_creation_input_tokens": 10791,
   "cache_read_input_tokens": 52277,
   "output_tokens": 3196,
   "output_tokens_details": {
    "thinking_tokens": 1407
   },
   "server_tool_use": {
    "web_search_requests": 0,
    "web_fetch_requests": 0
   },
   "service_tier": "standard",
   "cache_creation": {
    "ephemeral_1h_input_tokens": 10791,
    "ephemeral_5m_input_tokens": 0
   },
   "inference_geo": "global",
   "iterations": [
    {
     "input_tokens": 2,
     "output_tokens": 270,
     "cache_read_input_tokens": 20468,
     "cache_creation_input_tokens": 2862,
     "cache_creation": {
      "ephemeral_5m_input_tokens": 0,
      "ephemeral_1h_input_tokens": 2862
     },
     "type": "message"
    }
   ],
   "speed": "standard",
   "fallback_credit": null
  },
  "modelUsage": {
   "claude-sonnet-5-5": {
    "inputTokens": 6,
    "outputTokens": 3196,
    "cacheReadInputTokens": 52277,
    "cacheCreationInputTokens": 10791,
    "webSearchRequests": 0,
    "costUSD": 0.0803637,
    "contextWindow": 1000000,
    "maxOutputTokens": 128000,
    "thinkingTokens": 1407,
    "canonicalModel": "claude-sonnet-5-5",
    "provider": "firstParty",
    "costBasis": "list"
   }
  },
  "permission_denials": [],
  "terminal_reason": "completed",
  "fast_mode_state": "off",
  "fast_mode_disabled_reason": "sdk_opt_in_required",
  "subagent_stats": {
   "spawned": 0,
   "requested": {
    "background": 0,
    "foreground": 0,
    "unset": 0
   },
   "started_in_background": 0,
   "max_depth": 0,
   "spawned_by_subagents": 0,
   "completed": 0,
   "failed": 0,
   "killed": {
    "parent": 0,
    "user": 0,
    "system": 0
   },
   "refused": {
    "depth_limit": 0,
    "concurrency_limit": 0,
    "budget": 0
   },
   "by_type": {}
  },
  "safety_stops": 0,
  "is_error": false,
  "num_turns": 3,
  "subtype": "success",
  "api_error_status": null,
  "result": "I rewrote `redact(line)` in `redact.py` to apply the seven rules in order, each on the output of the one before. It reproduces `sample.expected.log` exactly on all 40 lines. I didn't run anything else, so the hidden checks and edge cases the sample doesn't cover are untested.\n\nIt uses only the standard library. Word characters are treated as ASCII-only, as in your spec.\n\nWhere the spec was ambiguous, I made these choices:\n- **IPv6:** a run with trailing punctuation, such as `2001:db8::5.`, is taken as one run. `ipaddress` rejects it, so it stays unchanged.\n- **IPv4:** the match is greedy over `digits(.digits)+`. A trailing `.` after a valid address, as at the end of a sentence, doesn't block redaction.",
  "ttft_ms": 1747,
  "type": "result",
  "duration_ms": 23500,
  "uuid": "[REDACTED]",
  "ttft_stream_ms": 1009,
  "time_to_request_ms": 242,
  "first_content_frame_ms": 1010,
  "queued_turn_count": 0,
  "result_index": 0
 }
]

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