GPT-5.4 Nano (Reasoning)

openai/gpt-5.4-nano

GPT-5.4 Nano (Reasoning)

via OpenRouter

Release Date

Mar 17th, 2026

Context Size

400k

Reasoning

Yes

Benchmark Cost

$1.70

Speed

133.2 tok/s

Subcategories

Bad Writing Habits

Detects common prose quality anti-patterns in AI-generated creative writing, including passive voice, past progressive overuse, weak dialogue tags, filter words, purple prose, cliches, AI-ism words/adverbs/names, and more.

Scenario	#1	#2	#3	#4	#5	Total
Detailed Writing Rules
Fantasy: entering an ancient ruin Creative Writing Hallucination	82	79	79	77	76	79%
Horror: alone in an eerie place at night Creative Writing Hallucination	88	83	82	82	80	83%
Literary fiction: old friends reunite Creative Writing Hallucination	86	86	84	82	81	84%
Mystery: examining a crime scene Creative Writing Hallucination	85	85	82	82	81	83%
Romance: separated couple reunites Creative Writing Hallucination	86	85	85	81	80	83%
Thriller: chase through city streets Creative Writing Hallucination	87	83	83	80	79	82%
Detailed Writing Rules						82.41%
genre
Fantasy: entering an ancient ruin Creative Writing Hallucination	79	75	75	73	73	75%
Horror: alone in an eerie place at night Creative Writing Hallucination	80	78	78	77	71	77%
Literary fiction: old friends reunite Creative Writing Hallucination	85	81	79	78	76	80%
Mystery: examining a crime scene Creative Writing Hallucination	82	80	79	77	74	78%
Romance: separated couple reunites Creative Writing Hallucination	80	78	77	76	75	78%
Thriller: chase through city streets Creative Writing Hallucination	82	82	81	77	74	79%
genre						77.74%
Novelcrafter Default Prompt
Fantasy: entering an ancient ruin Creative Writing Hallucination	81	80	77	76	74	78%
Horror: alone in an eerie place at night Creative Writing Hallucination	85	84	83	83	80	83%
Literary fiction: old friends reunite Creative Writing Hallucination	84	83	82	80	79	82%
Mystery: examining a crime scene Creative Writing Hallucination	88	84	83	82	81	84%
Romance: separated couple reunites Creative Writing Hallucination	80	79	78	77	76	78%
Thriller: chase through city streets Creative Writing Hallucination	86	82	80	79	78	81%
Novelcrafter Default Prompt						80.81%
80.32%

Codex Extraction

Evaluates a model's ability to extract structured codex entries (characters, locations, objects, lore) from prose passages and return them as well-formed XML.

Scenario	#1	#2	#3	#4	#5	Total
Long: The Spire of Echoes (Dense) Tooling Reasoning	95	94	93	92	90	93%
Medium: The Hollow (Inferred) Tooling Reasoning	95	93	92	91	90	92%
Medium: Through the Thornveil (Scattered) Tooling Reasoning	93	92	89	88	74	87%
Short: The Rusty Lantern (Explicit) Tooling Reasoning	98	97	97	96	92	96%
92.04%

Codex Red Herring (False Positive Detection)

Tests whether models correctly report "no violations" when a codex is fully consistent with the prose passage. Models that hallucinate false violations (false positives) fail. Uses a 2×2 matrix of text length × codex size, with bare and detailed-entry variants.

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
basic entries
Long text (~1594 words), big codex (51 entries) Hallucination	100	100	100	100	100	17	17	17	17	17	58%
Long text (~1594 words), small codex (11 entries) Hallucination	100	100	100	100	100	100	100	100	100	100	100%
Short text (~524 words), big codex (51 entries) Hallucination	100	100	100	100	100	100	100	100	100	100	100%
Short text (~524 words), small codex (11 entries) Hallucination	100	100	100	100	100	100	100	100	100	100	100%
basic entries											89.58%
detailed entries
Long text (~1594 words), big codex (51 detailed entries) Hallucination	100	100	100	100	100	100	100	100	100	100	100%
Long text (~1594 words), small codex (11 detailed entries) Hallucination	100	100	100	100	100	100	100	100	100	25	93%
Short text (~524 words), big codex (51 detailed entries) Hallucination	100	100	100	100	100	100	100	100	100	100	100%
Short text (~524 words), small codex (11 detailed entries) Hallucination	100	100	100	100	100	100	100	100	100	100	100%
detailed entries											98.13%
93.85%

Codex Violation Detection

Detects factual inconsistencies between a story bible and prose passages. The model must output structured XML identifying each violation with paragraph number and substring.

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
matrix
Large codex (40 entries), long passage (1,019 words) Tooling Reasoning	92	92	90	88	88	85	85	82	0	0	70%
Large codex (40 entries), short passage (165 words) Tooling Reasoning	95	95	93	92	90	90	88	88	87	83	90%
Small codex (7 entries), long passage (734 words) Tooling Reasoning	93	92	88	88	88	84	84	83	79	0	78%
Small codex (7 entries), short passage (165 words) Tooling Reasoning	100	100	100	100	100	100	100	97	97	0	89%
matrix											81.91%
tiers
5 codex entries Tooling Reasoning	100	100	100	100	100	100	100	97	93	0	89%
10 codex entries Tooling Reasoning	100	100	100	100	100	94	92	92	86	0	87%
20 codex entries Tooling Reasoning	94	91	91	91	91	88	0	0	0	0	55%
40 codex entries Tooling Reasoning	97	97	97	83	67	3	0	0	0	0	44%
tiers											68.61%
75.26%

Data extraction

Extract key details from a given block of text.

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
All valid emails Utility	100	100	100	100	100	100	100	100	100	100	100%
Contextual pronoun Utility	100	100	100	100	100	100	100	100	100	100	100%
Fruits excluding citrus Utility	100	100	100	100	100	100	100	100	100	0	90%
Future event time Reasoning	100	100	100	100	100	100	100	100	50	50	90%
Guess the pet Reasoning	100	100	100	100	100	100	100	100	100	100	100%
Highest-rated movie Reasoning	100	100	100	100	100	100	100	100	100	100	100%
Indirect birth year Reasoning	100	100	100	100	100	100	100	100	100	100	100%
What instrument does Lucy play? Reasoning	100	100	100	100	100	100	100	100	100	100	100%
What's the color of the car? Utility	100	100	100	100	100	100	100	100	100	100	100%
What's the correct time? Reasoning	0	0	0	0	0	0	0	0	0	0	0%
Who's the sister? Reasoning	100	100	100	100	100	100	100	100	100	100	100%
Who's the tallest? Reasoning	100	100	100	100	100	100	100	100	100	100	100%
90.00%

Dialogue tags

Various tasks related to dialogue tags in text.

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
dialogue-200
Write 200 words with 10% dialogue Rule Following Utility	100	100	100	100	100	100	100	100	100	99	100%
Write 200 words with 50% dialogue Rule Following Utility	100	100	100	100	100	100	100	100	99	50	95%
Write 200 words with 90% dialogue Rule Following Utility	100	100	97	86	80	70	68	50	50	50	75%
dialogue-200											89.96%
dialogue-500
Write 500 words with 30% dialogue Rule Following Utility	7	0	0	0	0	0	0	0	0	0	1%
Write 500 words with 50% dialogue Rule Following Utility	72	55	50	49	43	26	10	1	0	0	31%
Write 500 words with 70% dialogue Rule Following Utility	50	34	1	1	1	0	0	0	0	0	9%
dialogue-500											13.32%
Ungrouped
Write unattributed dialogue Rule Following	61	14	14	1	0	0	0	0	0	0	9%
45.53%

Language Comprehension

Does the model understand more than just English?

Scenario	#1	#2	#3	#4	#5	Total
Asking for directions (Dutch) Language	100	100	100	100	100	100%
Asking for directions (German) Language	100	0	0	0	0	20%
Friend got new kittens (German) Language	100	100	100	0	0	60%
Friend got new kittens (Tagalog) Language	100	100	100	100	100	100%
70.00%

Language Writing

Can the model generate text in different languages?

Scenario	#1	#2	#3	#4	#5	Total
Character dialogue (French) in a story Language	100	100	100	100	100	100%
Character dialogue (German) in a story Language	100	100	100	100	100	100%
Character dialogue (Hindi) in a story Language	100	100	100	100	56	91%
Character dialogue (Italian) in a story Language	100	100	100	100	98	100%
Character dialogue (Spanish) in a story Language	100	100	100	98	98	99%
97.99%

N-Length Sentences

Write sentences with exactly N words

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
Write sentences with 5 words each Utility	100	100	100	100	100	100	100	100	100	100	100%
Write sentences with 10 words each Utility	100	100	100	100	100	100	100	100	100	100	100%
Write sentences with 20 words each Utility	100	100	100	100	100	100	100	100	100	100	100%
100.00%

Novel outline

Handle questions about the outline of a novel in various formats

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
outline-count
Count acts Utility	100	100	100	100	100	100	100	100	100	100	100%
Count chapters Utility	100	100	100	100	100	100	100	100	100	100	100%
Count scenes Utility	100	100	100	100	100	0	0	0	0	0	50%
outline-count											83.33%
pov-count
Count point of views for Jack and Olivia Utility	100	100	100	100	100	100	100	100	100	100	100%
Count point of views for Jack Harper Utility	100	100	100	100	100	100	100	0	0	0	70%
Count point of views for Olivia Utility	100	100	100	100	100	100	100	100	100	0	90%
pov-count											86.67%
85.00%

Text Replacement

Tests deterministic text transformations: renaming characters/locations, expanding contractions, tense rewriting, POV shifts, gender swaps, combined transformations, and word avoidance. Scored by checking each expected change independently.

Scenario	#1	#2	#3	#4	#5	#6	#7	Total
Generic Prompt
Avoid said/asked/replied/answered Text Editing	100	100	100	100	97	89	86	96%
Character rename: Elena->Mirabel, Gregor->Aldric Text Editing	100	100	100	100	100	100	100	100%
Combined: 3rd person past → 1st person present Text Editing	99	99	99	98	95	95	90	97%
Expand all contractions Text Editing	99	98	98	98	98	98	98	98%
Location rename: market square, outer ring, bridge, northern mines Text Editing	100	96	96	96	96	96	96	96%
Multi-character gender swap: Priya(F)->Rohan(M), Mara unchanged Text Editing	100	99	92	88	74	74	73	86%
Passive voice → active voice Text Editing Hallucination	78	75	73	72	72	71	71	73%
POV shift: 3rd person to 1st person (Elena's perspective) Text Editing	100	100	100	100	100	100	100	100%
Tense rewriting: past to present Text Editing	96	96	96	95	95	95	91	95%
Generic Prompt								93.46%
Specific Prompt
Avoid said/asked/replied/answered Text Editing	100	100	100	100	89	89	89	95%
Character rename: Elena->Mirabel, Gregor->Aldric Text Editing	100	100	100	100	100	100	100	100%
Combined: 3rd person past → 1st person present Text Editing	99	99	99	97	97	95	93	97%
Expand all contractions Text Editing	99	98	98	98	97	97	91	97%
Location rename: market square, outer ring, bridge, northern mines Text Editing	100	100	100	100	100	100	100	100%
Multi-character gender swap: Priya(F)->Rohan(M), Mara unchanged Text Editing	99	99	98	98	95	95	95	97%
Passive voice → active voice Text Editing Hallucination	95	88	87	84	83	82	78	85%
POV shift: 3rd person to 1st person (Elena's perspective) Text Editing	100	100	100	100	100	99	99	100%
Tense rewriting: past to present Text Editing	100	100	100	99	93	93	89	96%
Specific Prompt								96.38%
94.92%

Tool usage within Novelcrafter

Output messages that are related to tool usage within Novelcrafter

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
Create alternate prose sections Tooling	100	100	100	100	100	100	100	100	100	100	100%
100.00%

Voice/dialogue sheets

Extract dialogue from given text as voice sheets.

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
Multiple speakers Rule Following	0	0	0	0	0	0	0	0	0	0	0%
Simple Rule Following	0	0	0	0	0	0	0	0	0	0	0%
Simple (1-shot) 1-shot Rule Following	100	100	100	100	0	0	0	0	0	0	40%
Simple (5-shot) Few-shot Rule Following	100	100	100	100	100	100	100	100	0	0	80%
Unattributed dialogue Rule Following	0	0	0	0	0	0	0	0	0	0	0%
24.00%

Write N of X

Write exactly N words/sentences/paragraphs...

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
paragraphs
1 paragraph summary Utility	100	100	100	100	100	100	100	100	100	100	100%
3 paragraph summary Utility	100	100	100	100	100	100	100	100	100	100	100%
5 paragraph summary Utility	100	100	100	100	100	100	100	100	100	100	100%
paragraphs											100.00%
sentences
1 sentence summary Utility	100	100	100	100	100	100	100	100	100	100	100%
3 sentence summary Utility	100	100	100	100	100	100	100	100	100	100	100%
10 sentence summary Utility	100	100	100	100	100	100	100	100	98	98	100%
20 sentence summary Utility	100	100	100	100	100	100	100	100	98	92	99%
50 sentence summary Utility	100	100	100	100	100	100	100	77	27	0	80%
sentences											95.83%
words
10 word summary Utility	100	100	100	100	100	100	100	100	100	100	100%
20 word summary Utility	100	100	100	100	100	100	100	100	100	100	100%
50 word summary Utility	100	100	100	100	100	100	100	100	100	98	100%
100 word summary Utility	100	100	100	100	100	100	100	100	100	100	100%
200 word summary Utility	100	100	100	100	100	100	100	98	98	98	99%
words											99.86%
98.34%