Claude Sonnet 5.5 (effort default (no --effort flag) · thinking on) on Compute library overdue fines with renewals, closed days, grace periods and hand-typed patron ids

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

Trust 80%Fully autonomoussuccess · first tryCompare

Estimated cost: $0.06
Wall time: 16s
Human step-ins: 0
Outcome: Pass

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Exact prompt

# Library overdue fines across branches Inputs: `loans.csv`, `renewals.csv`, `rates.json` (per item type: fine per day, cap per loan, grace days), `calendar.json` (closed dates and the as-of date). Rules: - Patron ids were typed by hand at different branches: "P-0412", "p0412", "P 412" and "P0412" are the same patron. Report ids as "P" followed by 4 digits (e.g. "P0412"). - A loan's due date is its original due date unless it was renewed. With several renewals, the one with the latest `renewed_at` timestamp sets the due date (staff corrections can move it earlier). File order means nothing. - Open days are all dates except Sundays and the dates in calendar.json `closed`. - Late open days = open days after the due date, up to and including the return date (or the as-of date if the item is not returned). - The first `grace_days` late open days are free. Fine = per_day x the remaining late open days, but never more than the item type's cap. - capped_loans = loans whose fine hit the cap, sorted by loan_id. - A patron is blocked when their total fines are 10.00 or more. Write `out/fines.json`: `{"patrons": {"<P####>": <total fines>, ...}, "blocked": [<P####>, ...], "capped_loans": [<loan_id>, ...], "total_usd": <n>}`. List only patrons with a total above 0. blocked is sorted. ## How this run works - Work on your own: nobody will answer questions in this task, and writing to `ask/` counts against the run. - Write only under `out/`. Create `out/` if it is missing. Inputs are synthetic; don't fetch anything from the network. - Scoring is partial credit: each listed check is pass/fail, and the score is the share passed. Numbers are compared to within 0.005 unless the task says otherwise.

Compute per-patron overdue fines from about 2,000 loans and their renewals. Late days count only open days (no Sundays or listed closures), with per-type grace days and caps. The latest renewal by timestamp sets the due date even when a staff correction moved it earlier, and patron ids typed in several formats must be merged before block thresholds apply. All money is whole cents. 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: patron_totals patron_ids_merged blocked capped_loans total

Setup notes: Batch 17 case s03-library-overdue-fines (offline, synthetic inputs, seed 2016818388). Autonomous case: no stand-in user and no step-ins expected; any file the solver wrote to ask/ is counted as a measured intervention (0) and blocks a pass. Prompt = TASK.md verbatim. Hidden key kept outside the solver's work dir. Scored with the case's scorer (python3 score.py WORKDIR KEYDIR, absolute paths); pass = every check true and no ask/ files. Tools: Read/Write/Edit/Glob/Grep/Bash, web disabled. Single run, no retries. 1-min load average at scoring 0.35 (8 cores). Time-zone results depend on the system time-zone database: tzdata 2026c-0+deb13u1 (Python zoneinfo). Claude Code's own reported cost for claude-sonnet-5.5: $0.055668. Score: 5/5. 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: $0.06
Wall time: 16s
Human step-ins: 0
Turns: 4

Model usage
Model	Input tok	Output tok	Cost
AClaude Sonnet 5.5anthropic/claude-sonnet-5.5effort default (no --effort flag) · thinking on	78,412	1,582	$0.06

Reproduce this run

Use the use case prompt on the use case page.
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.
It counts as a success only if it meets every success criterion: patron_totals patron_ids_merged blocked capped_loans total
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).

Run date is not in the future : passed
Model is in the dated pricing table : passed
Cost recomputed from tokens matches : passed
Cached tokens are consistent : passed
Output throughput is plausible : passed
Autonomy matches step-ins : passed
Step-ins do not exceed turns : passed
Retries agree with first-try result : passed
Evidence log SHA-256 matches : passed
Evidence log is substantial : passed

Evidence log

[
 {
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  "stop_reason": "end_turn",
  "session_id": "[REDACTED]",
  "total_cost_usd": 0.0556681,
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   "cache_read_input_tokens": 70201,
   "output_tokens": 1582,
   "output_tokens_details": {
    "thinking_tokens": 35
   },
   "server_tool_use": {
    "web_search_requests": 0,
    "web_fetch_requests": 0
   },
   "service_tier": "standard",
   "cache_creation": {
    "ephemeral_1h_input_tokens": 8203,
    "ephemeral_5m_input_tokens": 0
   },
   "inference_geo": "global",
   "iterations": [
    {
     "input_tokens": 2,
     "output_tokens": 274,
     "cache_read_input_tokens": 19906,
     "cache_creation_input_tokens": 836,
     "cache_creation": {
      "ephemeral_5m_input_tokens": 0,
      "ephemeral_1h_input_tokens": 836
     },
     "type": "message"
    }
   ],
   "speed": "standard",
   "fallback_credit": null
  },
  "modelUsage": {
   "claude-sonnet-5-5": {
    "inputTokens": 8,
    "outputTokens": 1582,
    "cacheReadInputTokens": 70201,
    "cacheCreationInputTokens": 8203,
    "webSearchRequests": 0,
    "costUSD": 0.0556681,
    "contextWindow": 1000000,
    "maxOutputTokens": 128000,
    "thinkingTokens": 35,
    "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
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   "refused": {
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    "concurrency_limit": 0,
    "budget": 0
   },
   "by_type": {}
  },
  "safety_stops": 0,
  "is_error": false,
  "num_turns": 4,
  "subtype": "success",
  "api_error_status": null,
  "result": "I wrote `out/fines.json`.\n\n- **Patrons with fines:** 379.\n- **Blocked patrons:** 230, meaning total fines of 10.00 or more.\n- **Capped loans:** 425, meaning loans whose fine reached the item type's cap.\n- **Total fines:** 6400.60 USD.\n\nI didn't spot-check any individual loans by hand, so the output rests on the script's logic alone.\n\n- **Patron ids:** I normalised them to \"P\" plus 4 digits by stripping everything but the digits.\n- **Renewals:** each loan uses the new due date from its latest `renewed_at`, whatever the file order.\n- **Late days:** counted after the due date through the return date, or the as-of date (2026-10-20) if the item isn't returned. Sundays and the `closed` dates are skipped.",
  "ttft_ms": 2588,
  "type": "result",
  "duration_ms": 14838,
  "uuid": "[REDACTED]",
  "ttft_stream_ms": 1752,
  "time_to_request_ms": 236,
  "first_content_frame_ms": 1753,
  "queued_turn_count": 0,
  "result_index": 0
 }
]