Open Library Trending Books rank_change climbers via get_top_trends

Open Library rank_change on Trends MCP is get_top_trends with type Open Library Trending Books, sort rank_change, and a window such as 1d. From the August 29, 2026 pull, the board stamped 2026-08-29T06:01:55 UTC. The 1d window used baseline 2026-08-28T02:01:40 UTC and returned 36 climbers after paging: 25 at offset 0, then 11 at offset 25. The 7d window used baseline 2026-08-22T02:01:34 UTC and returned count 15, then count 0 at offset 15 with a held-or-fell note. Default sort rank filled 200 titles, then count 0 at offset 200. Rank 1 was Atomic Habits - James Clear, absent from the 1d climber list. The Art of War led 1d at rank 9, prev_rank 163, rank_change 154. Free tier access is 100 requests per month.

Open Library 7d returned 15 climbers while 1d returned 36

From the Trends MCP scan of August 29, 2026, Open Library Trending Books sort rank_change stamped 2026-08-29T06:01:55 UTC and filled 36 climber rows on window 1d, 26 on 3d, 15 on 7d, 27 on 14d, and 34 on 30d, so a default sort rank pull at limit 25 never lists these mover fields.

Shared as_of 2026-08-29T06:01:55 UTC:

1d filled 25 at offset 0, then 11 at offset 25 (limit 50). 3d filled 25, then 1 more at offset 25: Atomic Habits at rank 1, prev_rank 2, rank_change 1. 7d filled 15, then count 0 at offset 15 with a held-or-fell note. 14d filled 25, then 2 at offset 25. 30d filled 25, then 9 at offset 25. Quote the count after paging. Limit 25 on a 36-row 1d list hides Psychology of Money at rank 2, prev_rank 11, rank_change 9.

The 1d baseline sat on the previous day's 02:01 clock, not 24 hours before the 06:01 as_of. That gap is about 28 hours. Wikipedia Trending 1d on the same stamp and the same 02:01 baseline returned 28 climbers, led by Grand Theft Auto VI at rank 21, prev_rank 157, rank_change 136. A 36-row Open Library list is not interchangeable with that Wikipedia list.

Open Library 1d climbers (first 12 of 36):

The Art of War tied O Alquimista at +154. The Art of War keyword string on the board includes a CJK author name plus Stephen F. Kaufman and Lionel Giles. Shorten to The Art of War before a growth call. Two later 1d rows used non-ASCII titles; those strings were skipped here rather than transliterated.

Default sort rank on the same stamp closed at 200: 25 rows at offset 0, 50 at offset 25, 50 at offset 150, then count 0 at offset 200. Rank 1 was Atomic Habits - James Clear. Rank 2 was The Psychology of Money - Morgan Housel. Rank 198 was Atomic Habits with no author. The Open Library Trending Books API page still describes a 25-row scan stamped 2026-08-06T06:01:36 UTC. That limit was a page size. This pull filled 200.

Exact API calls for book climber boards

sort rank_change plus window is a separate get_top_trends request from default sort rank, so a 1d climber pull and a current-rank pull on August 29, 2026 are two requests, and each extra window is another request because window is per call.

{
  "mode": "get_top_trends",
  "type": "Open Library Trending Books",
  "sort": "rank_change",
  "window": "1d",
  "limit": 50
}

{
  "mode": "get_top_trends",
  "type": "Open Library Trending Books",
  "sort": "rank_change",
  "window": "7d",
  "limit": 50
}

{
  "mode": "get_top_trends",
  "type": "Open Library Trending Books",
  "limit": 50,
  "offset": 0
}

MCP clients send the same fields on get_top_trends. The type string is exact: Open Library Trending Books is correct; Open Library fails. Window values are 1d, 3d, 7d, 14d, and 30d. Default sort is rank. Default window when sort is rank_change is 30d, so omit window only when that 30d lookback is the intent. On this stamp the 30d call returned 34 climbers after paging, not the 15-row 7d list. Offset and limit behavior is on get_top_trends pagination. For a page-view sibling, see Wikipedia Trending rank_change. For a title-board sibling, see IMDb MOVIEmeter rank_change.

Open Library's own search.json trending sort, documented in the project's August 6, 2025 engineering post, is a z-score of last-24-hour activity versus the prior 7 days. That payload exposes trending_z_score. It does not emit prev_rank against a stored Trends MCP snapshot. Those products are not substitutes.

Rank 1 Atomic Habits sat outside the 1d climber list

A current rank 1 title can be missing from rank_change when it held or fell, because rank_change only lists titles that climbed versus the stored snapshot, and Atomic Habits sat at rank 1 on August 29, 2026 without appearing on the 36-row 1d list.

It showed up later as a +1 on other windows: 3d offset 25 put Atomic Habits at rank 1, prev_rank 2, rank_change 1. 14d offset 25 did the same. 7d and 30d never listed it. Harry Potter and the Philosopher's Stone, rank 5 on the current board, sat on 1d offset 25 at prev_rank 6, rank_change 1, and led the 15-row 7d list at prev_rank 97, rank_change 92.

get_growth is a 0-100 index for a shortened title, not a live catalog rank. Follow-ups use google search or amazon, each billed as its own request. amazon 7D collapsed on every title in this run: recent and baseline resolved to the same data point. wikipedia 7D also collapsed for The Art of War, and wikipedia returned unavailable for The Mountain Is You and The Psychology of Money.

On the 2026-08-22 google search points (260 weekly values), The Art of War sat at 27.0, down 28.95% over 7 days from 38.0, down 56.45% over 30 days from 62.0, and down 61.43% over 3 months from 70.0. That falling 27.0 sat next to the largest 1d board climb, +154. amazon for The Art of War printed index 34.6 on 2026-07-31, with 34,996 recent volume, down 15.4% over 30 days from 41,415. wikipedia printed 26.6 on 2026-07-01, with 129 recent page views, down 22.9% over 30 days from 34.5.

The Mountain Is You, rank 4 and a 1d climber at +68, sat at google search 48.0 on 2026-08-22, down 4.0% over 7 days from 50.0. amazon printed 26.4 with 59,497 recent volume, nearly flat over 30 days at -1.12% from 26.7, up 8.64% over 3 months from 24.3. The Psychology of Money, rank 2, sat at google search 30.0, down 18.92% over 7 days from 37.0, while amazon printed 43.3 with 73,298 recent volume, up 10.74% over 30 days from 39.1 and up 46.28% over 3 months from 29.6. wikipedia was unavailable for both titles.

Atomic Habits, still rank 1, sat at google search 45.0, down 4.26% over 7 days from 47.0. amazon printed 20.1 with 220,063 recent volume, up 6.91% over 30 days from 18.8, flat at 20.1 over 3 months. Harry Potter sat at google search 29.0, flat over 7 days from 29.0, up 16.0% over 30 days from 25.0 (260 points). amazon printed 24.9 with 3,163,616 recent volume, up 10.67% over 30 days from 22.5. Dracula, the 30d leader at +172, sat at google search 31.0, down 3.12% over 7 days from 32.0. amazon printed 22.1 with 189,744 recent volume, up 4.74% over 30 days from 21.1, down 43.62% over 3 months from 39.2. Animal Farm, rank 6 and a 1d climber at +13, sat at google search 32.0, flat over 7 days, down 13.51% over 30 days from 37.0. amazon printed 33.4 with 123,805 recent volume.

Live rank is not a get_growth guarantee. Quote both values. A +154 Open Library climb for The Art of War is not the same story as google search falling from 38.0 to 27.0. Strip authors, translation prefixes, and CJK glyphs before those follow-ups. The board does not expose Open Library z-scores, borrow counts, or ISBN inventory.