Claude Opus 5.5 (effort default (no --effort flag) · thinking on) on Find substantive changes hidden in a 'minor clean-up' contract redline

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

Trust 80%Fully autonomoussuccess · first trySupersededCompare

Estimated cost: $0.19
Wall time: 38s
Human step-ins: 0
Outcome: Pass

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Superseded. This run was rescored on 2026-10-28 and replaced by a newer run. It no longer counts toward rankings, use-case tables or the data export; it is kept here for the record.

Exact prompt

# Task: review a contract redline for the customer You represent the CUSTOMER. `msa_v1.txt` is the agreed draft; `msa_v2.txt` is the provider's new version, described by them as "minor clean-up only". Compare them. Write `changes.json`: a list of objects for every SUBSTANTIVE change (one that changes rights, obligations, amounts, durations, scope, or removes a clause). Ignore purely cosmetic edits (whitespace, capitalisation, punctuation, rephrasing with identical meaning). Each object: {"clause": "<number e.g. 2.2>", "kind": one of ["notice_period","payment_terms","cap_or_limit","duration","scope_narrowed","scope_broadened","ownership","new_obligation","governing_law","clause_removed","other"], "customer_impact": "worse"|"better"|"neutral", "summary": "<one sentence>"} Also write `memo.md` (≤250 words) telling the customer which 3 changes matter most and why. No network.

Review a contract redline for the customer: compare the agreed draft with a 'minor clean-up' version from the provider and list every substantive change. Ten real changes, some subtle (a liability cap cut from 50% to 15%, a dropped 'gross negligence' carve-out, a deleted clause), are mixed with eight cosmetic edits that should not be flagged. 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: 1. changes.json must flag at least 9 of the 10 substantive changes (matched by clause number). 2. The 'kind' value must be correct for at least 8 of the substantive changes. 3. At most 1 clause that only has cosmetic edits may be flagged. 4. customer_impact must be 'worse' for at least 9 of the substantive changes. 5. memo.md must exist and be <= 250 words.

Setup notes: Use Case Scout batch 3 case c06-contract-redline (offline fixture). Prepared with batch3/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/key.json`. Tools: Read/Write/Edit/Glob/Grep/Bash, web disabled. Single run, no retries. Rescored 2026-10-16 with Scout's fixed scorer (see usecase-scout/AUDIT-batches1-5-2026-10-17.md). The original score was fail, and the model's output is unchanged. Claude Code's own reported cost for claude-opus-5.5: $0.187645. Score: pass. 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: 38s
Human step-ins: 0
Turns: 10

Model usage
Model	Input tok	Output tok	Cost
AClaude Opus 5.5anthropic/claude-opus-5.5effort default (no --effort flag) · thinking on	180,475	2,687	$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: 1. changes.json must flag at least 9 of the 10 substantive changes (matched by clause number). 2. The 'kind' value must be correct for at least 8 of the substantive changes. 3. At most 1 clause that only has cosmetic edits may be flagged. 4. customer_impact must be 'worse' for at least 9 of the substantive changes. 5. memo.md must exist and be <= 250 words.
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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    "contextWindow": 1000000,
    "maxOutputTokens": 128000,
    "thinkingTokens": 462,
    "canonicalModel": "claude-opus-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": {
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  "subtype": "success",
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  "result": "I compared the two versions and wrote both files. The provider called v2 \"minor clean-up only\", but it makes **10 substantive changes, and every one is worse for the customer**.\n\n**`changes.json`: the 10 substantive changes**\n| Clause | Change |\n|---|---|\n| 1.2 | Notice to stop auto-renewal goes from 90 to 120 days |\n| 2.2 | Payment due in 30 days from the invoice date, instead of 45 days from receipt |\n| 3.2 | Service-credit cap cut from 50% to 15% of monthly fees |\n| 4.1 | Confidentiality after termination cut from 5 years to 2 |\n| 5.2 | Gross negligence removed from the exclusions, so the provider's liability for it is now capped |\n| 6.1 | Data no longer EU-only; the provider can also store it in the United States |\n| 7.1 | Ownership of outputs moves from the customer to the provider |\n| 8.1 | New early termination fee of 3 months' fees when the customer terminates for convenience |\n| 9.1 | Governing law changes from Ireland to New York, which no longer fits the exclusive Dublin courts in 9.2 |\n| 10.3 | The customer's audit right is deleted entirely |\n\nThe remaining edits are cosmetic: spacing, the capital \"F\" in \"Fees\", commas, \"e-mail\", \"that precede\" and \"shall have\". I left them out.\n\n**`memo.md`** (248 words by `wc -w`) recommends rejecting the redline and going back to v1. It names these three changes as mattering most:\n1. **Data location and audit (6.1 + 10.3):** together these create GDPR exposure on transfers outside the EU, and the customer loses the only way to check where its data is.\n2. **Output ownership (7.1):** the provider would own work product the customer is paying for.\n3. **Liability and service credits (5.2 + 3.2):** the customer has much less recourse, both for gross negligence and for routine service-level failures.\n\nThe memo also lists the other five changes to push back on.\n\nOn labelling: 5.2 and 8.1 could each fit more than one category. I tagged 5.2 as `cap_or_limit` and 8.1 as `new_obligation`.",
  "ttft_ms": 1851,
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  "uuid": "[REDACTED]",
  "ttft_stream_ms": 776,
  "time_to_request_ms": 200,
  "first_content_frame_ms": 777,
  "queued_turn_count": 0,
  "result_index": 0
 }
]