Claude Sonnet 5.5 (effort default (no --effort flag) · thinking on) on Run a bookkeeping client's fixed-asset depreciation for 2026 with a mid-month convention, straight-line and declining-balance methods, and disposals

AClaude Sonnet 5.5default · thinking on · Claude Code 2.1.299 (headless -p) · cloud · 2026-10-24 · by @bobsiopener

Trust 80%Fully autonomousfail · 0 retriesCompare

Estimated cost: $0.05
Wall time: 13s
Human step-ins: 0
Outcome: Fail

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Exact prompt

# Run a bookkeeping client's fixed-asset depreciation for 2026 with a mid-month convention, straight-line and declining-balance methods, and disposals Inputs: `assets.csv` (asset_id, category, cost, salvage, life_months, method, in_service, disposed_on, proceeds) for a small business client of a bookkeeping firm. All records are synthetic; amounts are in dollars. These rules are the firm's policy; where `controller-note.txt` disagrees, the rules win. Rules: - Mid-month convention: an asset placed in service on day 1-15 of a month starts depreciating that month; on day 16 or later, it starts the next month. An asset disposed of on day 1-15 of a month gets no depreciation for that month; on day 16 or later it gets that month's depreciation, and none after it. - Schedule: depreciation is charged month by month from the asset's first month (which may be before 2026) until life_months monthly charges have been made or the asset is disposed of. Book value = cost − accumulated depreciation. - Straight line (method SL): every monthly charge is (cost − salvage) / life_months, rounded half-up to the cent, except the last month of the life, whose charge is whatever brings accumulated depreciation to exactly cost − salvage. - Double declining (method DDB): a month's charge is the larger of (a) the opening book value × 2 / life_months and (b) (opening book value − salvage) / the number of monthly charges left including this one, each rounded half-up to the cent, but never more than opening book value − salvage. - Disposal: gain_loss = proceeds − (cost − accumulated depreciation at disposal), counting only the depreciation the convention allows. A disposed asset leaves the register: its accum_2026_12_31 and nbv_2026_12_31 are 0, but its 2026 charges still count in dep_2026. - Write `out/fixed-assets.json`: `{"assets": {"<asset_id>": {"dep_2026": <depreciation charged in 2026>, "accum_2026_12_31": <dollars>, "nbv_2026_12_31": <dollars>}, ...}, "disposals": {"<asset_id>": <gain_loss>, ...}, "by_category": {"<category>": <sum of dep_2026>, ...}}`. ## 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.

Run a year of depreciation on a small business's synthetic fixed-asset register for its bookkeeping firm. A mid-month convention decides the first and last charged months, straight-line charges are rounded with a last-month true-up, double-declining charges move to the remaining-life charge once that is larger and stop at salvage, and disposals produce a gain or loss and leave the register. Dates sit on the 15th/16th boundary. A controller's note gets the convention, the switch and the salvage 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: mid_month_convention straight_line declining_balance disposals register_totals

Setup notes: Batch 35 case tw01-bookkeeping-fixed-asset-depreciation (offline, synthetic inputs, seed 2941314334). 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 0.65 (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: $0.054586. Score: 2/5. 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: $0.05
Wall time: 13s
Human step-ins: 0
Turns: 3

Model usage
Model	Input tok	Output tok	Cost
AClaude Sonnet 5.5anthropic/claude-sonnet-5.5effort default (no --effort flag) · thinking on	59,041	1,586	$0.05

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: mid_month_convention straight_line declining_balance disposals register_totals
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 ran the 2026 depreciation for all eight assets and wrote the result to `out/fixed-assets.json`. I haven't checked the figures independently beyond the run itself.\n\nI followed the firm's rules throughout. That means the mid-month convention, the DDB formula with the remaining-life floor and the salvage cap, and disposal gains measured against book value after depreciation. The controller's note disagrees on all of these, so I ignored it.\n\n| Asset | 2026 depreciation | Disposal gain/loss |\n|---|---|---|\n| FA-639 | 6,832.35 | \u221213,020.53 |\n| FA-267 | 1,131.36 | |\n| FA-295 | 8,534.62 | 4,778.05 |\n| FA-663 | 953.24 | |\n| FA-583 | 2,585.52 | |\n| FA-563 | 8,490.00 | |\n| FA-989 | 8,692.08 | |\n| FA-962 | 803.73 | \u22122,984.71 |\n\nFA-639, FA-295 and FA-962 were disposed of in 2026. They show zero accumulated depreciation and zero net book value at year end, but their 2026 charges still count in the depreciation column above.\n\nDepreciation by category:\n- **Office furniture:** 9,417.87\n- **Vehicles:** 10,627.17\n- **Computers:** 8,534.62\n- **Workshop machinery:** 9,443.24",
  "ttft_ms": 1695,
  "type": "result",
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  "uuid": "[REDACTED]",
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  "time_to_request_ms": 199,
  "first_content_frame_ms": 938,
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 }
]