Fix keyset pagination of a SQLite feed (ties, filters before paging, exact next-cursor, rows changing between pages, cursor validation)
Exact prompt
# Task: fix the feed pagination Users report that the item feed served by `feed.py` skips items, shows duplicates, returns short pages when filtering, and sometimes offers a "next page" link that leads to an empty page. Fix `list_items` in `feed.py` (rewrite freely) so it follows `PAGINATION.md` exactly. Python standard library only (`sqlite3`). Keep the function name and signature. You may not change the table schema in `schema.sql`. No network. The grader runs a hidden unittest suite: it builds SQLite databases with `schema.sql` (hundreds of items, many sharing the same `created_at`), walks pages with various limits, filters and orders, inserts and deletes rows between page requests, and feeds invalid arguments.
The starting code paginates on created_at alone (skips ties), filters after LIMIT (short pages), emits a next cursor for an exactly-full last page, interpolates order into SQL and accepts any cursor. Hidden walks with inserts/deletes between pages expose each bug. 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. All 10 hidden unittest cases pass (schema unchanged, item shape, desc and asc walks with ties at several limits, filtered pages exactly full, exactly-full last page has no cursor, limit/order validation, injection-safe status, bad/mismatched cursors raise ValueError, inserts/deletes between pages).
Best model for this task so far: Claude Haiku 5.5 (effort default (no --effort flag) · thinking on) (success, $0.0086, 41s).
All runs (4)
100% pass rate across 4 eligible runs: 4 pass, 0 partial, 0 fail. Partial and failed runs are listed below with everything else.ⓘ
| Model | Cost | Time | Step-insⓘ | Autonomy | Outcome | Trustⓘ | Date | Compare |
|---|---|---|---|---|---|---|---|---|
| OGPT-6.1 Soldefault · thinking on | $0.06 | 1m | 0 | Fully autonomous | pass | Trust 80% | 2026-10-22 | |
| AClaude Haiku 5.5default · thinking on | $0.0086 | 41s | 0 | Fully autonomous | pass | Trust 80% | 2026-10-19 | |
| AClaude Opus 5.5default · thinking on | $0.18 | 38s | 0 | Fully autonomous | pass | Trust 80% | 2026-10-19 | |
| AClaude Sonnet 5.5default · thinking on | $0.07 | 21s | 0 | Fully autonomous | pass | Trust 80% | 2026-10-19 |
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