Claude Haiku 5.5 (effort default (no --effort flag) · thinking on) on Migrate a 3-file Node.js module from callbacks to async/await + fix a validation bug

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: $0.0082
Wall time: 38s
Human step-ins: 0
Outcome: Pass

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Exact prompt

# Task: migrate a small Node.js codebase from callbacks to async/await `lib/store.js`, `lib/inventory.js`, `lib/orders.js` use Node-style callbacks. Convert ALL three to promise-returning `async` functions (same function names and arguments minus the callback; results become resolved values, errors become rejections with the same messages). Keep behaviour identical, including order rollback on failure. While you're there, fix this reported bug: `removeStock` accepts zero/negative/NaN quantities; it must reject with the same message as `addStock` ("qty must be positive") and not change stock. Update `test/` to the new API and add tests. Run `npm test` (node --test). No new dependencies, no network.

Hidden node:test suite checks every API became promise-based, error messages preserved, rollback semantics kept, and the qty bug fixed. Partial migrations or rollback regressions fail. 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. Hidden node:test file is copied into test/ and `node --test test/` must exit 0 (60 s timeout); the agent's own tests in test/ must also pass. 2. Hidden tests check: store/inventory/orders functions return promises with the same results; errors become rejections with the original messages; addStock rejects 0/NaN; removeStock rejects zero/negative quantities with 'qty must be positive' and leaves stock unchanged; insufficient stock rejects without changes; listStock correct; fulfil succeeds and on failure rolls back already-removed lines. 3. No callback usage left in lib/*.js (no `cb(` / `callback(`) and each file uses async or Promise.

Setup notes: Use Case Scout batch 4 case d01-js-callbacks-to-async (offline fixture). Prepared with batch4/prepare.sh; hidden key/tests kept outside the agent's work dir. Prompt = TASK.md verbatim. Scored with the scout's scorer: `bash score.sh WORKDIR`. Tools: Read/Write/Edit/Glob/Grep/Bash, web disabled. Single run, no retries. Claude Code's own reported cost for claude-haiku-5.5: $0.008158. 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: $0.0082
Wall time: 38s
Human step-ins: 0
Turns: 11

Model usage
Model	Input tok	Output tok	Cost
AClaude Haiku 5.5anthropic/claude-haiku-5.5effort default (no --effort flag) · thinking on	118,655	7,880	$0.0082

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: 1. Hidden node:test file is copied into test/ and `node --test test/` must exit 0 (60 s timeout); the agent's own tests in test/ must also pass. 2. Hidden tests check: store/inventory/orders functions return promises with the same results; errors become rejections with the original messages; addStock rejects 0/NaN; removeStock rejects zero/negative quantities with 'qty must be positive' and leaves stock unchanged; insufficient stock rejects without changes; listStock correct; fulfil succeeds and on failure rolls back already-removed lines. 3. No callback usage left in lib/*.js (no `cb(` / `callback(`) and each file uses async or Promise.
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.

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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": "The three modules are now promise-based `async` functions, the `removeStock` bug is fixed, and `npm test` passes: 12 tests across three files, up from 1.\n\n**What changed**\n- **`lib/store.js`**: `get`, `put`, and `keys` return promises. The 1ms simulated latency is kept, and a non-string key rejects with `key must be string` after the same delay as before.\n- **`lib/inventory.js`**: `addStock`, `removeStock`, and `listStock` resolve with the same values as before. `removeStock` now rejects zero, negative, and NaN quantities with `qty must be positive` before reading stock, so stock is never touched.\n- **`lib/orders.js`**: `fulfil` still resolves (not rejects) with `status: 'rejected'` and the error message when a line fails. Rollback still restores earlier lines in forward order, and failed restores are ignored as before.\n- **Tests**: I replaced `test/basic.test.js` with `store.test.js`, `inventory.test.js`, and `orders.test.js`. The old callback flow test is now the \"fulfil removes stock\" case. New coverage includes the `removeStock` fix and the rollback path. Each file resets the store before every test.\n\n**Behaviour change to be aware of**\n- An order line with `qty: 0` used to succeed silently. It now fails and triggers rollback, with the reason `qty must be positive`. This follows directly from the bug fix, but it is a visible change for any caller that sent zero-quantity lines.\n\n**Notes**\n- The directory is not a git repo, so I made no commit and the attribution lines did not apply.\n- I did not run the old `removeStock` against the new tests to confirm they catch the bug. The NaN and zero cases exercise the new guard directly, so I'm confident in them, but I did not check that by reverting the fix.",
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