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Claude Fable 5.2 vs GLM 5.3 Flash

Claude Fable 5.2 leads GLM 5.3 Flash on coding, 87.8 to 56.2 on the Vibe Coding Index, and GLM 5.3 Flash costs 80.0x less per output token ($0.50 vs $40.00 per million). Updated November 14, 2026; 48 benchmarks have a result for both.

Replace Claude Fable 5.2 Replace GLM 5.3 Flash
Claude Fable 5.2Anthropic
Coding
87.8
Overall
91.7
Output $/M
$40.00
47
GLM 5.3 FlashZ.ai
Coding
56.2
Overall
61.8
Output $/M
$0.50
1
vs boards won of 48 shared

Claude Fable 5.2 or GLM 5.3 Flash: which to pick

Pick Claude Fable 5.2 for coding: it scores 87.8 on the Vibe Coding Index against 56.2 for GLM 5.3 Flash, though on 4 benchmarks against 6.

Pick GLM 5.3 Flash for output tokens 80.0x cheaper ($0.50 vs $40.00 per million) and a larger context window (1.05M against 1M tokens).

Model AClaude Fable 5.2Anthropic87.8/1004 independent benchmarksNo cost per solved taskModel BGLM 5.3 FlashZ.ai56.2/1006 independent benchmarks$0.02 per solved task
Shared results
48
Claude Fable 5.2 only
20
GLM 5.3 Flash only
67
Like-for-like categories
8 of 9

Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.

Which one for your work

Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.

At a glance

Coding index
Claude Fable 5.2 87.8 from 4 benchmarks, GLM 5.3 Flash 56.2 from 6 benchmarks.
Widest category
Math, 51.8 points apart on average over 4 shared benchmarks.
Widest single gap
FrontierMath, tier 4: Claude Fable 5.2 100.0% against GLM 5.3 Flash 17.1%, 82.9 points apart on a 0 to 100 scale.
Output price
Claude Fable 5.2 $40.00 against GLM 5.3 Flash $0.50 per million output tokens, 80.0x apart.
Context window
Claude Fable 5.2 takes 1M tokens, GLM 5.3 Flash 1.05M.

Benchmark by benchmark

First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.

Boards won, where both have a result
CategoryClaude Fable 5.2BarsGLM 5.3 FlashTies
Coding140
Intelligence20
Agentic work71
Reasoning90
Math40
Knowledge10
Web design60
General40
All shared boards471
CodingLike-for-likeSix of these boards feed the Vibe Coding Index140
Coding benchmarks for Claude Fable 5.2 and GLM 5.3 Flash
BenchmarkClaude Fable 5.2GLM 5.3 FlashLeader
LiveBench coding79.2%70.9%Claude Fable 5.2
LMArena WebDev18381609Claude Fable 5.2
AA Coding IndexNot measured71.5Only GLM 5.3 Flash measured
LiveCodeBench (Vals AI)Not measured80.5%Only GLM 5.3 Flash measured
SWE-bench Verified (Vals AI)Not measured92.0%Only GLM 5.3 Flash measured
Terminal-Bench 4 (Vals AI)65.2%37.4%Claude Fable 5.2
Vibe Code Bench (Vals AI)93.8%30.8%Claude Fable 5.2
Code migration (Vals AI)Not measured20.5%Only GLM 5.3 Flash measured
ProgramBench (Vals AI)19.0%0.0%Claude Fable 5.2
IOI (Vals AI)Not measured52.5%Only GLM 5.3 Flash measured
Terminal-Bench 2.1 (Vals AI)Not measured62.9%Only GLM 5.3 Flash measured
SWE-bench Multimodal (Vals AI)62.3%Not measuredOnly Claude Fable 5.2 measured
Vibe Code Bench 1-100 (Vals AI)Not measured16.0%Only GLM 5.3 Flash measured
SkillsBench (Vals AI)Not measured40.2%Only GLM 5.3 Flash measured
CyberBench (Vals AI)Not measured67.9%Only GLM 5.3 Flash measured
SciCode67.7%51.6%Claude Fable 5.2
Terminal-Bench 4.0 (Artificial Analysis run)61.6%32.8%Claude Fable 5.2
FrontierCode 2.049.1%17.6%Claude Fable 5.2
FrontierCodeNot measured31.8%Only GLM 5.3 Flash measured
FrontierSWE69.9%18.1%Claude Fable 5.2
ALE-Bench2509.8303.6Claude Fable 5.2
LMArena Text: codingNot measured1509Only GLM 5.3 Flash measured
LMArena Text: software and ITNot measured1501Only GLM 5.3 Flash measured
LMArena WebDev: React19151628Claude Fable 5.2
LMArena WebDev: HTML17381576Claude Fable 5.2
LMArena WebDev: from an imageNot measured1582Only GLM 5.3 Flash measured
GameBench 299.160.8Claude Fable 5.2
Terminal-Bench 4.0Not measured36.7%Only GLM 5.3 Flash measured
CursorBench 4.060.0%36.8%Claude Fable 5.2
Neither model has a result on the other 23 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Claude Fable 5.2 and GLM 5.3 Flash
BenchmarkClaude Fable 5.2GLM 5.3 FlashLeader
AA Intelligence Index64.627.8Claude Fable 5.2
Epoch Capabilities Index173.4153.8Claude Fable 5.2
Agentic workLike-for-likePublic boards, shown as published, kept out of the index71
Agentic work benchmarks for Claude Fable 5.2 and GLM 5.3 Flash
BenchmarkClaude Fable 5.2GLM 5.3 FlashLeader
AA Agentic IndexNot measured50.9Only GLM 5.3 Flash measured
Design Arena: agents building full-stack apps1402Not measuredOnly Claude Fable 5.2 measured
Design Arena: agents building mobile apps1325Not measuredOnly Claude Fable 5.2 measured
Design Arena: spreadsheets1434Not measuredOnly Claude Fable 5.2 measured
LiveBench research94.5%73.9%Claude Fable 5.2
LiveBench browser86.9%59.8%Claude Fable 5.2
LiveBench long agentic82.9%20.7%Claude Fable 5.2
SREBench (Vals AI)Not measured0.8%Only GLM 5.3 Flash measured
Finance Agent (Vals AI)Not measured57.9%Only GLM 5.3 Flash measured
Tax Agent Bench (Vals AI)32.1%31.6%Claude Fable 5.2
Legal Research Bench (Vals AI)46.1%45.2%Claude Fable 5.2
Harvey's Legal Agent Benchmark (Vals AI)5.0%10.4%GLM 5.3 Flash
Excel Modeling Benchmark (Vals AI)Not measured55.9%Only GLM 5.3 Flash measured
BioMysteryBench (Vals AI)83.7%Not measuredOnly Claude Fable 5.2 measured
Terminal-Bench-Science (Vals AI)55.7%2.9%Claude Fable 5.2
Vals Science Index63.7%Not measuredOnly Claude Fable 5.2 measured
APEX-Agents80.1%52.8%Claude Fable 5.2
Remote Labor Index41.3%Not measuredOnly Claude Fable 5.2 measured
PostTrainBenchNot measured36.8%Only GLM 5.3 Flash measured
SpireClimb15.5%Not measuredOnly Claude Fable 5.2 measured
Toolathlon-VerifiedNot measured78.4%Only GLM 5.3 Flash measured
Neither model has a result on the other 23 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index90
Reasoning benchmarks for Claude Fable 5.2 and GLM 5.3 Flash
BenchmarkClaude Fable 5.2GLM 5.3 FlashLeader
GPQA DiamondNot measured86.4%Only GLM 5.3 Flash measured
LiveBench reasoning88.8%77.6%Claude Fable 5.2
MysteryMechanism (Vals AI)51.8%Not measuredOnly Claude Fable 5.2 measured
MMMU Pro (Vals AI)Not measured86.0%Only GLM 5.3 Flash measured
GPQA Diamond (Artificial Analysis run)Not measured91.2%Only GLM 5.3 Flash measured
Humanity's Last Exam (Artificial Analysis run)74.3%39.9%Claude Fable 5.2
HLE-Diamond (Artificial Analysis run)80.2%18.2%Claude Fable 5.2
CritPt v2, hard subset (Artificial Analysis run)76.5%24.5%Claude Fable 5.2
GPQA Diamond (Epoch AI run)93.9%90.2%Claude Fable 5.2
ARC-AGI98.5%91.0%Claude Fable 5.2
ARC-AGI-293.8%65.8%Claude Fable 5.2
SimpleBench94.9%Not measuredOnly Claude Fable 5.2 measured
Chess puzzles79.0%21.0%Claude Fable 5.2
Mystery game puzzles90.0%8.0%Claude Fable 5.2
EBR-bench90.5%Not measuredOnly Claude Fable 5.2 measured
LMArena Text: hard promptsNot measured1490Only GLM 5.3 Flash measured
LMArena Text: expertNot measured1511Only GLM 5.3 Flash measured
LMArena Text: hard prompts in EnglishNot measured1492Only GLM 5.3 Flash measured
LMArena Vision: diagramsNot measured1321Only GLM 5.3 Flash measured
LMArena Vision: homeworkNot measured1323Only GLM 5.3 Flash measured
Humanity's Last Exam (Scale run)72.4%Not measuredOnly Claude Fable 5.2 measured
GoBench2566Not measuredOnly Claude Fable 5.2 measured
Neither model has a result on the other 4 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index40
Math benchmarks for Claude Fable 5.2 and GLM 5.3 Flash
BenchmarkClaude Fable 5.2GLM 5.3 FlashLeader
OTIS Mock AIME99.7%93.9%Claude Fable 5.2
FrontierMath, tiers 1 to 395.1%55.8%Claude Fable 5.2
FrontierMath, tier 4100.0%17.1%Claude Fable 5.2
ProofBench100.0%21.0%Claude Fable 5.2
LMArena Text: mathNot measured1503Only GLM 5.3 Flash measured
LMArena Text: mathematical workNot measured1491Only GLM 5.3 Flash measured
MathArena82.8%Not measuredOnly Claude Fable 5.2 measured
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index10
Knowledge benchmarks for Claude Fable 5.2 and GLM 5.3 Flash
BenchmarkClaude Fable 5.2GLM 5.3 FlashLeader
MMLU ProNot measured86.1%Only GLM 5.3 Flash measured
LegalBench (Vals AI)Not measured83.9%Only GLM 5.3 Flash measured
TaxEval (Vals AI)Not measured75.6%Only GLM 5.3 Flash measured
AA-Omniscience66.80.7Claude Fable 5.2
SimpleQA Verified94.0%Not measuredOnly Claude Fable 5.2 measured
LMArena Text: scienceNot measured1485Only GLM 5.3 Flash measured
LMArena Text: medicine and healthcareNot measured1480Only GLM 5.3 Flash measured
LMArena Text: legal and governmentNot measured1478Only GLM 5.3 Flash measured
LMArena Text: business and financeNot measured1461Only GLM 5.3 Flash measured
PRBench Finance47.1%Not measuredOnly Claude Fable 5.2 measured
PRBench Legal49.0%Not measuredOnly Claude Fable 5.2 measured
Neither model has a result on the other 10 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index60
Web design benchmarks for Claude Fable 5.2 and GLM 5.3 Flash
BenchmarkClaude Fable 5.2GLM 5.3 FlashLeader
Design Arena: websites13511257Claude Fable 5.2
Design Arena: UI components13711296Claude Fable 5.2
Design Arena: game dev13961266Claude Fable 5.2
Design Arena: data vizNot measured1258Only GLM 5.3 Flash measured
Design Arena: 3D15171292Claude Fable 5.2
Design Arena: all code categories13731267Claude Fable 5.2
Design Arena: SVGNot measured1271Only GLM 5.3 Flash measured
Design Arena: ASCII artNot measured1269Only GLM 5.3 Flash measured
LiveBench design85.1%73.7%Claude Fable 5.2
GeneralLike-for-likePublic boards, shown as published, kept out of the index40
General benchmarks for Claude Fable 5.2 and GLM 5.3 Flash
BenchmarkClaude Fable 5.2GLM 5.3 FlashLeader
Vals Index71.3%50.9%Claude Fable 5.2
LiveBench data analysis81.5%76.4%Claude Fable 5.2
SAGE (Vals AI)Not measured89.3%Only GLM 5.3 Flash measured
MedScribe (Vals AI)Not measured88.9%Only GLM 5.3 Flash measured
Long context reasoning (AA-LCR)83.3%80.0%Claude Fable 5.2
GDPval-AA18311648Claude Fable 5.2
DTBench99.2%Not measuredOnly Claude Fable 5.2 measured
LMCA70.6%Not measuredOnly Claude Fable 5.2 measured
Surface Evolver BenchNot measured52.5%Only GLM 5.3 Flash measured
Furniture assembly90.0%Not measuredOnly Claude Fable 5.2 measured
LMArena TextNot measured1472Only GLM 5.3 Flash measured
LMArena Text: instruction followingNot measured1480Only GLM 5.3 Flash measured
LMArena Text: creative writingNot measured1442Only GLM 5.3 Flash measured
LMArena VisionNot measured1295Only GLM 5.3 Flash measured
LMArena Text: EnglishNot measured1477Only GLM 5.3 Flash measured
LMArena Text: non-EnglishNot measured1462Only GLM 5.3 Flash measured
LMArena Text: ChineseNot measured1528Only GLM 5.3 Flash measured
LMArena Text: GermanNot measured1452Only GLM 5.3 Flash measured
LMArena Text: JapaneseNot measured1453Only GLM 5.3 Flash measured
LMArena Text: KoreanNot measured1427Only GLM 5.3 Flash measured
LMArena Text: FrenchNot measured1489Only GLM 5.3 Flash measured
LMArena Text: SpanishNot measured1476Only GLM 5.3 Flash measured
LMArena Text: RussianNot measured1467Only GLM 5.3 Flash measured
LMArena Text: PolishNot measured1448Only GLM 5.3 Flash measured
LMArena Text: multi-turnNot measured1471Only GLM 5.3 Flash measured
LMArena Text: longer queriesNot measured1481Only GLM 5.3 Flash measured
LMArena Text: writing and languageNot measured1457Only GLM 5.3 Flash measured
LMArena Text: entertainment and mediaNot measured1442Only GLM 5.3 Flash measured
LMArena Vision: EnglishNot measured1299Only GLM 5.3 Flash measured
LMArena Vision: ChineseNot measured1359Only GLM 5.3 Flash measured
LMArena Vision: reading textNot measured1303Only GLM 5.3 Flash measured
LMArena Vision: humorNot measured1291Only GLM 5.3 Flash measured
LMArena Vision: recognizing thingsNot measured1279Only GLM 5.3 Flash measured
LMArena Vision: creative writingNot measured1272Only GLM 5.3 Flash measured
Neither model has a result on the other 15 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Claude Fable 5.2 and GLM 5.3 Flash
BenchmarkClaude Fable 5.2GLM 5.3 FlashLeader
Neither model has a result on 5 boards here

What each workload costs

Three fixed token mixes at each model's listed price, so per-token rates become a bill.

Chat turn

1K input + 500 output tokens

Claude Fable 5.2$0.028Fits in one request
GLM 5.3 Flash$0.0004Fits in one request

GLM 5.3 Flash costs less

Repository review

50K input + 3K output tokens

Claude Fable 5.2$0.520Fits in one request
GLM 5.3 Flash$0.0090Fits in one request

GLM 5.3 Flash costs less

Agent loop

200K input + 10K output tokens

Claude Fable 5.2$2.00Fits in one request
GLM 5.3 Flash$0.035Fits in one request

GLM 5.3 Flash costs less

Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.

Specification differences

The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.

Specifications of Claude Fable 5.2 and GLM 5.3 Flash
SpecificationAnthropic Claude Fable 5.2Z.ai GLM 5.3 Flash
MakerAnthropicZ.ai
WeightsNo public weights listedOpen weights
ReleasedNovember 9, 2026August 26, 2026
Context window1M1.05M
Input $/Mtok$8.00$0.15
Output $/Mtok$40.00$0.50
Coding index87.856.2
Independent measurements behind it46
Cost per solved taskNot computable$0.02
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Fable 5.2 better than GLM 5.3 Flash for coding?

Pick Claude Fable 5.2 for coding: it scores 87.8 on the Vibe Coding Index against 56.2 for GLM 5.3 Flash, though on 4 benchmarks against 6. Pick GLM 5.3 Flash for output tokens 80.0x cheaper ($0.50 vs $40.00 per million) and a larger context window (1.05M against 1M tokens).

Which is cheaper, Claude Fable 5.2 or GLM 5.3 Flash?

Claude Fable 5.2 costs $8.00 per million input tokens and $40.00 per million output tokens; GLM 5.3 Flash costs $0.15 and $0.50. Cost per solved task is known for GLM 5.3 Flash only.

Which has the bigger context window, Claude Fable 5.2 or GLM 5.3 Flash?

GLM 5.3 Flash, with 1.05M tokens against 1M.

How many benchmarks is the Claude Fable 5.2 vs GLM 5.3 Flash comparison based on?

48 benchmarks have a result for both models as of November 14, 2026. Claude Fable 5.2's coding index rests on 4 independent benchmarks and GLM 5.3 Flash's on 6. Where only one model has a result, the page says so instead of naming a winner.

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