Claude Haiku 5.5 (effort default (no --effort flag) · thinking on) on Reconcile a messy CSV ledger against bank statements

AClaude Haiku 5.5default · thinking on · Claude Code 2.1.299 (headless -p) · cloud · 2026-10-16 · by @bobsiopener

Trust 80%Fully autonomoussuccess · first tryCompare

Estimated cost: $0.02
Wall time: 2m
Human step-ins: 0
Outcome: Pass

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Exact prompt

You are the bookkeeper for Bramble & Oak Bakery LLC. This folder contains ledger.csv (the general ledger for the business checking account, July-September 2026; amount > 0 is a deposit, amount < 0 is a payment; the opening book balance on July 1, 2026 was 48,213.57 and agreed with the bank) and three bank statement PDFs (statement_2026-07.pdf, statement_2026-08.pdf, statement_2026-09.pdf). pdftotext is installed. Reconcile the ledger against the bank statements for the whole quarter. Ledger entries are often dated 0-3 days before the bank posts them, and ledger descriptions differ from bank descriptions; neither of those is a discrepancy. Report only real discrepancies. Write two files in this folder: 1. discrepancies.csv with header: type,ledger_entry_ids,bank_date,bank_amount,ledger_amount,explanation - type is one of: duplicate_in_ledger, amount_mismatch, sign_error, missing_in_ledger (on the bank statement but not in the ledger), missing_in_bank (in the ledger but never on any statement) - ledger_entry_ids: the ledger entry_id(s) involved, separated by ';' (empty for missing_in_ledger) - bank_date as YYYY-MM-DD (empty if not on the bank statement); amounts as signed numbers without $ or commas 2. reconciliation.json with keys: bank_closing_balance_2026_09_30, ledger_closing_balance_2026_09_30 (opening balance plus all ledger entries), sum_of_adjustments (the net amount your discrepancies add to the ledger balance to reach the bank balance), unexplained_difference (bank closing minus ledger closing minus sum_of_adjustments).

Reconciling a bakery's three-month checking-account ledger (about 1,800 rows) against three PDF bank statements. Twenty-five discrepancies are seeded (duplicates, transposed digits, sign errors and items missing on either side), plus legitimate look-alike purchases as false-positive traps. The agent must list every discrepancy and make the balances reconcile to zero. 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: Finds all 25 seeded discrepancies with ≤ 2 false positives; totals match.

Setup notes: Synthetic bakery checking account: ledger.csv (1821 rows, Jul-Sep 2026) and 3 bank statement PDFs (reportlab) generated by batch2/p07/gen.py (seed 7071026) with 25 seeded discrepancies (6 duplicates, 6 transposed amounts, 3 sign errors, 6 bank-only items, 4 ledger-only items) plus 3 legitimate identical same-day purchases as false-positive traps. Tools: Read/Write/Edit/Glob/Grep/Bash (pdftotext available), web disabled. Scored by batch2/p07/score_p07.py. The financial documents were generated synthetically by a script (not real records). Claude Code's own reported cost for claude-haiku-5.5: $0.023169. Score: 25/25 found, 0 false positives. 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: $0.02
Wall time: 2m
Human step-ins: 0
Turns: 10

Model usage
Model	Input tok	Output tok	Cost
AClaude Haiku 5.5anthropic/claude-haiku-5.5effort default (no --effort flag) · thinking on	380,864	20,257	$0.02

Reproduce this run

Use the use case prompt on the use case page.
Same setup: Claude Haiku 5.5 (anthropic/claude-haiku-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: Finds all 25 seeded discrepancies with ≤ 2 false positives; totals match.
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 `discrepancies.csv` (25 rows) and `reconciliation.json` to the work folder. The reconciliation ties out with zero unexplained difference.\n\n**Reconciliation**\n- Bank closing balance 2026-09-30: 233,555.55\n- Ledger closing balance 2026-09-30: 230,221.86 (opening 48,213.57 plus all 1,821 ledger entries)\n- Sum of adjustments: 3,333.69\n- Unexplained difference: 0.00\n\n**Discrepancies by type**\n- **duplicate_in_ledger (6):** a second ledger copy of a transaction the bank posted only once. Staples, Shell (\u00d72), Starbucks (\u00d73).\n- **amount_mismatch (6):** the same transaction recorded at a different amount, such as Staples 19.71 vs 17.91 and Square 2,659.80 vs 2,659.08.\n- **sign_error (3):** two refunds and one customer check recorded as payments, while the bank shows credits (Costco 226.88, Amazon 148.27, check 1,401.38).\n- **missing_in_ledger (6):** wire transfer fee 25.00, two monthly service fees of 35.00, NSF returned item fee 36.00, ADP insurance premium 612.40, and interest 4.18.\n- **missing_in_bank (4):** ledger entries with no bank counterpart on any statement: L00852 (48.19), L01050 (137.58), L01120 (49.23), L01739 (52.75).\n\n**Choices I made**\n- The 20 ledger entries dated June 28\u201330 are in the ledger balance as instructed. They all match July bank postings, so they are not discrepancies.\n- For duplicates, I listed both ledger IDs and left `bank_date` and `bank_amount` empty, since the extra copy never appears on a statement. The explanation names the single bank posting.\n- For sign errors and amount mismatches, `ledger_amount` is the ledger's signed amount and `bank_amount` is the bank's signed amount.\n\nI checked the statement running balances and the header totals for all three months, and they agree with the extracted transactions.",
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