Claude Opus 5.5 (effort default (no --effort flag) · thinking on) on Required minimum distributions from a supplied divisor table, with and without delaying the first one

AClaude Opus 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: $0.14
Wall time: 22s
Human step-ins: 0
Outcome: Pass

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Exact prompt

# Required minimum distributions from a supplied divisor table, with and without delaying the first one `input.json` describes retirement accounts, yearly growth, a **fictional** life-expectancy divisor table and fictional tax brackets. Write `solve.py` (Python 3 standard library only) so that `python solve.py input.json answer.json` builds the year-by-year distribution schedule for two choices and compares the tax. Use only the rules below and the input. We re-run it on fresh inputs, so do not hard-code anything. ## Input `birth_year`, `start_age` (first age with a required distribution), `first_year` (first calendar year to simulate), `accounts` (each with `balance` = balance on Dec 31 of the year before `first_year`), `growth` (one yearly return per simulated year; the number of years simulated is its length), `other_income`, `brackets` (`[lower_bound, rate]` list as in a progressive tax), `divisor_table` (age as string -> divisor). ## Rules 1. All accounts are pooled: the balance is the sum of the account balances. 2. For calendar year Y (index j, Y = first_year + j) the age is Y - birth_year. If age >= start_age, the required amount is rmd = (balance on Dec 31 of the previous year) / divisor(age), else 0. For ages above the table's largest age use the largest age's divisor. 3. Withdrawals happen at the start of the year, then the balance grows: end balance = (previous balance - withdrawal) * (1 + growth[j]). 4. **no_delay**: withdrawal = min(balance, rmd) every year. 5. **delay_first**: the first year with rmd > 0 withdraws 0 and that rmd is carried to the next year, which withdraws min(balance, its own rmd + the carried amount). The next year's own rmd still uses its previous Dec 31 balance (which was not reduced by the carried amount). After that, same as no_delay. 6. Tax for a year = tax(other_income + withdrawal) - tax(other_income), using the progressive brackets: rate j applies to income above bound j up to bound j+1. 7. `lower_tax` = "no_delay" or "delay_first" (smaller total tax), or "same" if the totals differ by less than 0.005. 8. Round money to 2 decimals only when writing. ## Output `answer.json`: `{"no_delay": S, "delay_first": S, "lower_tax": ...}` where S = `{"rows": [{"year", "age", "rmd", "withdrawal", "tax", "end_balance"}, ... one per simulated year], "total_withdrawn", "total_tax", "final_balance"}`. ## Scoring Hidden checks (partial credit = fraction passed; all must pass), money within 0.011, years/ages/labels exact: `rmd_amounts_no_delay`, `totals_no_delay`, `delay_first_schedule`, `delay_first_totals_and_choice` on the given input; `fresh_run_1`, `fresh_run_2`: the whole answer on fresh inputs. Each run has a 60-second limit.

Pooled accounts, ages above the table, the carried first distribution that does not reduce the next year's base, and bunching tax under progressive brackets. 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).

These are synthetic test cases for comparing AI models, not financial advice.

Success criteria: 1. rmd_amounts_no_delay 2. totals_no_delay 3. delay_first_schedule 4. delay_first_totals_and_choice 5. fresh_run_1 6. fresh_run_2

Setup notes: Use Case Scout batch 9 case j06-required-distributions (offline fixture). Prepared with batch9/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-opus-5.5: $0.13822. 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: $0.14
Wall time: 22s
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	59,786	2,483	$0.14

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: 1. rmd_amounts_no_delay 2. totals_no_delay 3. delay_first_schedule 4. delay_first_totals_and_choice 5. fresh_run_1 6. fresh_run_2
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 `solve.py` and ran it on the given input. I also checked the first required-distribution year by hand, and the result matched what the script wrote to `answer.json`.\n\n**Result on the given input:** not delaying gives lower total tax.\n\n| | Total withdrawn | Total tax | Final balance |\n|---|---|---|---|\n| `no_delay` | 999,733.93 | 203,842.82 | 458,319.85 |\n| `delay_first` | 1,002,470.25 | 207,506.27 | 458,764.18 |\n\nDelaying costs about 3,663 more in tax. The person is 72 in 2029, so the first required distribution is in 2032 (age 75). Delaying it pushes two withdrawals into 2033, 86,504.89 in total, which is taxed at higher rates.\n\n**Hand check of 2032:**\n- The pooled balance of 870,000 grows to 933,771 at the end of 2029, and to 1,008,982.34 by the end of 2031.\n- 1,008,982.34 / 24.6 = 41,015.54 required.\n- On top of 60,000 other income, the tax is 36,900 \u00d7 18% + 4,115.54 \u00d7 26% = 7,712.04.\n\n**Cases the rules don't cover, and what the script does:**\n- **Ages missing from the divisor table:** an age above the table already uses the largest age's divisor, as the rules say. If an age between table entries is missing, the script uses the nearest lower age. If an age is below the smallest entry, it uses the smallest entry.\n- **Bracket order:** brackets are sorted by lower bound before the tax is computed.\n- **First distribution in the last simulated year:** under `delay_first`, that year withdraws 0 and the carried amount is never taken, because there is no next year.\n- **Rounding:** totals and the `lower_tax` choice use unrounded values. Rounding to 2 decimals happens only when the file is written.",
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