Vol. I · No. 1 · MMXXVI
NextChapterBench A Benchmark of Literary Continuation
23 models · 10 items · 1 judge

The Standings → Claude Opus 5

Live run data

Anthropic

Claude Opus 5

high reasoning effort · via Claude CLI · judged by Claude Sonnet 5 · not the setting shown on the standings; also run at xhigh79.2 medium71.5

Results from run ‘first’: ten items, ten verdicts.

Claude Opus 5 scores 77 on craft, 13 points above the field’s 63 and 16 points short of the authors themselves. Its shape differs from the field’s: relatively strong on folding the brief into the story, relatively weak on building scenes. On the mechanical checks it kept to the brief’s word range on 8 of 10 items, reproduced a 71-word run of the real book verbatim and is unusually free of stock phrases.

Headline 75.5 of 100 · compliance × craft
Compliance 98 of 100
Craft 77 of 100

The record: 10 items · 10 verdicts · 0 errors · 2,430 words on average · est. generation cost $2.02

Read the chapters in full

§ I

Craft by Dimension

Eight dimensions, each 0–100, averaged over ten items; the author’s real chapter was in the room every time.

Craft by dimension, 0–100 · judged by Sonnet 5 beside the author’s real chapter

Voice
78
Prose
77
Character
76
Scene
75
Integration
78
Momentum
76
Restraint
74
Specificity
78
0255075100
reader’s score, 0–100 · hollow tick: field average · filled tick: the authors themselves

The authors themselves average 93 on the five writing dimensions, the field 63, this model 77. Hover or focus a bar for the field and the authors on that dimension.

In plain words, item by item

The judge’s one-sentence best quality and worst flaw for each chapter, written for a general reader.


§ II

Per-Item Results

Headline, compliance and craft for each chapter, 0–100.

The same ten items in figures, with word counts.
Item Headline Compliance Craft Words
Persuasion item 001 · after ch. 1 · Jane Austen 80.6100812,613
The Moonstone item 011 · after ch. 8 · Wilkie Collins 78.8100792,787
The Secret Garden item 013 · after ch. 2 · Frances Hodgson Burnett 78.1100782,312
Red Harvest item 023 · after ch. 2 · Dashiell Hammett 77.5100782,497
Leave It to Psmith item 022 · after ch. 3 · P. G. Wodehouse 76.695813,190
Dracula item 015 · after ch. 5 · Bram Stoker 75.8100762,330
The War of the Worlds item 006 · after ch. 1 · H. G. Wells 75.695802,339
The Awakening item 016 · after ch. 7 · Kate Chopin 74.8100751,757
The Sun Also Rises item 021 · after ch. 3 · Ernest Hemingway 72.1100722,004
The Mysterious Affair at Styles item 017 · after ch. 3 · Agatha Christie 65.095682,475

§ III

Length Against the Brief

Words written per item, against each brief’s maximum.

Word count per item vs. brief maximum · run ‘first’

words written brief maximum
Persuasion
2,613
The Moonstone
2,787
The Secret Garden
2,312
Red Harvest
2,497
Leave It to Psmith
3,190
Dracula
2,330
The War of the Worlds
2,339
The Awakening
1,757
The Sun Also Rises
2,004
The Mysterious Affair at Styles
2,475
08001,6002,4003,200
words; the ink tick marks each brief’s maximum

Eight of ten items landed inside their brief’s word range. Persuasion and Leave It to Psmith ran over by 13 and 390 words respectively.


§ IV

Worst Flaws, as Recorded

Each verdict names the chapter’s single worst flaw, with evidence. Quoted verbatim from run ‘first’.

The chapter trips over its own stage directions: Poirot is said to tuck the green threads away in his breast pocket, but a few lines later the envelope is described as still 'in his hand,' and Poirot's promised ten-minute delay somehow stretches into an hour before he shows up.

on The Mysterious Affair at Styles, item 017 · Claude Sonnet 5

The ending has Psmith fondly re-reading the note's 'signature' as though it told him the girl's name, but earlier in the same chapter she deliberately signed it only 'The Girl Under the Awning' — the two moments contradict each other.

on Leave It to Psmith, item 022 · Claude Sonnet 5

The bank clerk is named Robert Albury and described almost exactly as 'a nice-looking blond youngster of twenty-five or six,' which is lifted nearly word for word from the real published book rather than freshly invented.

on Red Harvest, item 023 · Claude Sonnet 5

The narrator pauses to congratulate himself on being right in hindsight ('the only occasion in this whole history upon which I was in advance of the event'), which feels a little smug and breaks the retrospective spell.

on The War of the Worlds, item 006 · Claude Sonnet 5

§ V

The Mechanical Docket

Automated screening results across the ten outputs.