Claude Opus 5.5 (effort default (no --effort flag) · thinking on) on Audit a household bank statement for forgotten subscriptions, double charges and true delivery spend

AClaude Opus 5.5default · thinking on · Claude Code 2.1.299 (headless -p) · cloud · 2026-10-25 · by @bobsiopener

Trust 80%Fully autonomoussuccess · first tryCompare

Estimated cost: $0.19
Wall time: 31s
Human step-ins: 0
Outcome: Pass

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Exact prompt

# Audit a household bank statement for forgotten subscriptions, double charges and true delivery spend Inputs: `statement.csv` (txn_id, posted, description, amount), `merchants.csv` (merchant_id, match_text, category), `categories.csv` (category) and `last-used.csv` (merchant_id, last_used). The statement covers three whole calendar months. All people, merchants and transactions are synthetic; amounts are in dollars, a negative amount is money out (a debit) and a positive amount is money in (a credit). These rules are the household's; where `friend-tip.txt` disagrees, the rules win. Rules: - Matching: a transaction belongs to the merchant whose match_text appears in its description, ignoring letter case; at most one match_text appears in any description. A credit that matches no merchant (pay, transfers in) is ignored; every debit matches a merchant. - Forgotten subscriptions: a merchant in the 'subscriptions' category is forgotten when it has at least one debit in each of the three statement months and its last_used is blank or more than 60 days before the statement's last day; its annual cost is 12 × the amount of its most recent debit (as a positive number). - Double charges: take each merchant's debits in posted order (then txn_id order). A debit is a double charge when the debit just before it from the same merchant has exactly the same amount and was posted on the same day or the day before, unless a credit from that merchant of the same size is posted within 7 days after the double charge (on or before its posted date + 7). List the later debit of each pair. - Delivery spend: for each statement month, the debits from merchants in the 'delivery' category posted that month (orders, delivery fees, service fees and tips are separate lines and all count) minus the credits from those merchants posted that month. - Category spend: for each category in categories.csv, the category's debits minus its credits over the whole statement, as a positive dollar figure (double charges are still spend unless refunded). - Write `out/audit.json`: `{"forgotten_subscriptions": [<sorted merchant_ids>], "forgotten_annual_cost": <sum of their annual costs>, "double_charges": [<sorted txn_ids>], "double_charged_total": <sum of their amounts, as a positive number>, "delivery_by_month": {"<YYYY-MM>": <dollars>, ...}, "category_spend": {"<category>": <dollars>, ...}}`. - Roll-ups: Months in the statement with no delivery transactions are included at 0. Categories in categories.csv with no transactions are included at 0. ## 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.

Audit three months of a synthetic household's bank statement. Find subscriptions still charging every month that nobody has used for over 60 days, same-day or next-day double charges that were never refunded, and the true monthly delivery spend once fees, tips and refunds are counted. Some subscriptions changed price, one was last used exactly 60 days ago, and a refunded duplicate and a two-day repeat are decoys. The prompt says months and categories with no activity are listed at 0. A friend's tip gets the delivery, double-charge and roll-up rules wrong. 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: forgotten_subscriptions forgotten_annual_cost double_charges double_charged_total delivery_by_month category_spend

Setup notes: Batch 40 case tn01-household-statement-spending-audit (offline, synthetic inputs, seed 281729524). 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 0.19 (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-opus-5.5: $0.194775. Score: 6/6. 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: $0.19
Wall time: 31s
Human step-ins: 0
Turns: 4

Model usage
Model	Input tok	Output tok	Cost
AClaude Opus 5.5anthropic/claude-opus-5.5effort default (no --effort flag) · thinking on	89,818	3,108	$0.19

Reproduce this run

Use the use case prompt on the use case page.
Same setup: Claude Opus 5.5 (anthropic/claude-opus-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: forgotten_subscriptions forgotten_annual_cost double_charges double_charged_total delivery_by_month category_spend
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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  "result": "I wrote the audit to `out/audit.json`. The statement covers May to July 2026, so the last day is 2026-07-31.\n\n**Forgotten subscriptions:** three, costing **$623.64 a year** in total.\n- **MR-110** (Larkspur Video Club) and **MR-117** (Orchard Lane Fitness) were last used more than 60 days before July 31. Orchard Lane's annual cost uses its latest charge, $21.99.\n- **MR-145** (Saltmarsh Photo Vault) has no last-used date.\n- **MR-138** (Hollowbrook) was last used exactly 60 days before July 31. The rule needs *more than* 60, so it isn't listed.\n- **MR-131** (Pebblewick) has no charge in July, and **MR-124** (Quillfeather) was used recently, so neither counts.\n\n**Double charges:** five, totalling **$108.42**.\n- TX-40313: Bluebell Cafe, $19.21\n- TX-40318: Fuel Stop 41, $45.23\n- TX-40251: Metro Card Top-Up, $40.00 on consecutive days\n- TX-40081: Swiftcrate, $1.99\n- TX-40160: Bramblebox, $1.99\n\nThe Fuel Stop $13.94 pair on July 21 isn't listed because it was refunded on July 28, within the 7 days.\n\n**Decision for you:** TX-40081 and TX-40160 are a $1.99 delivery fee that came straight after a $1.99 service fee from the same shop on the same day. They're probably two different fees rather than a repeat. They're included because your rule only compares merchant, amount and date. If you'd rather not count them, the list drops to three and the total to $104.44.\n\n**Delivery spend by month:** this counts every order, fee and tip line, minus refunds.\n\n| Month | Spend |\n|---|---|\n| 2026-05 | $142.83 |\n| 2026-06 | $147.02 |\n| 2026-07 | $132.37 |\n\n**Category spend:** all ten categories are listed. Childcare and pets had no transactions, so they're at $0.\n\n| Category | Spend |\n|---|---|\n| Groceries | $1,348.31 |\n| Dining | $1,060.25 |\n| Transport | $667.85 |\n| Delivery | $422.22 |\n| Travel | $334.10 |\n| Health | $284.96 |\n| Subscriptions | $215.83 |\n| Utilities | $189.69 |\n| Childcare | $0 |\n| Pets | $0 |\n\nWhere the friend's tip disagreed with your rules (counting only order lines, using a whole week for repeats, leaving out empty categories), I followed your rules.",
  "ttft_ms": 2907,
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 }
]