All tasks / Comparisons

Claude Fable 5.1 vs GLM-5.3

Compared only on public benchmark results, across the 6 tasks where both are listed: Claude Fable 5.1 is a tier higher in 4 of 6 shared tasks, GLM-5.3 in 1, they share a tier in 1.

Claude Fable 5.1

Anthropic's highest-priced Claude tier, positioned for demanding reasoning and long-horizon agentic work.

Vendor: Anthropic
Weights: Closed: API and apps only
Released: 1 Sep 2026
API price: $10 in / $50 out per 1M tokens
License: proprietary
Last verified: 18 Oct 2026

Alternatives to Claude Fable 5.1

GLM-5.3

Z.ai's open-weights GLM model line for reasoning, coding and agentic tasks.

Vendor: Z.ai
Weights: Open: run it yourself
Released: 14 Aug 2026
API price: $1.4 in / $4.4 out per 1M tokens
GPU memory to run locally: ~425 GB
License: GLM-5.3 License (custom; HF tag 'glm-5.3'; LMArena lists MIT)
Last verified: 18 Oct 2026

Alternatives to GLM-5.3

Task by task

Task	Claude Fable 5.1	GLM-5.3	Higher tier
Chat & assistants Models	S1,502 on LMArena Text Arena (overall, style control) · Cloud	A1,479 on LMArena Text Arena (overall, style control) · Local	Claude Fable 5.1
Writing Models	S1,485 on LMArena Text Arena: Creative Writing (style control) · Cloud	A1,453 on LMArena Text Arena: Creative Writing (style control) · Local	Claude Fable 5.1
Coding Models	A1,742 on LMArena WebDev / Code Arena (overall) · Cloud	C1,622 on LMArena WebDev / Code Arena (overall) · Local	Claude Fable 5.1
Vector graphics & logos Models	C1,300 on Design Arena SVG · Cloud	C1,293 on Design Arena SVG · Local	Same tier
Workflow automation Models	C59.4% on AutomationBench-AA (Artificial Analysis) · Cloud	B62.2% on AutomationBench-AA (Artificial Analysis) · Local	GLM-5.3
Slides & presentations Models	S1,328 on Design Arena Python-PPTX Slides · Cloud	A1,255 on Design Arena Python-PPTX Slides · Local	Claude Fable 5.1

A tier spans a range of scores, and small gaps on a leaderboard are often within its margin of error, so only a different tier counts as ahead. How we rank.

Same benchmark, both results

Benchmark	Claude Fable 5.1	GLM-5.3	Snapshot
Artificial Analysis Intelligence Index Composite index over Artificial Analysis' own evaluation suite, higher is better	53 Claude Fable 5.1 (Max, Default Fallback)	45 GLM-5.3 (Max)	18 Oct 2026
AutomationBench-AA (Artificial Analysis) Score: average share of each task's objectives completed across 657 business-workflow tasks in 40 simulated SaaS apps via REST APIs; a task with any guardrail (business-rule) violation scores zero, higher is better	59.4% Claude Fable 5.1 (Max, Default Fallback)	62.2% GLM-5.3 (Max)	19 Oct 2026
Design Arena Python-PPTX Slides Elo rating from crowdsourced blind pairwise votes on PowerPoint decks that models build with python-pptx in Design Arena's agent harness, higher is better	1,328 Claude Fable 5.1	1,255 GLM-5.3	18 Oct 2026
Design Arena SVG Elo rating from crowdsourced blind pairwise votes on SVG markup that models generate from a prompt (icons, illustrations, diagrams, artistic compositions), higher is better	1,300 Claude Fable 5.1	1,293 GLM-5.3	19 Oct 2026
EQ-Bench Creative Writing v3 Elo score from LLM-judged pairwise comparisons of creative-writing outputs (rubric score shown alongside), higher is better	2,162 claude-fable-5-1	2,075 GLM-5.3	24 Sep 2026
LMArena Text Arena (overall, style control) Arena score (Bradley-Terry rating from pairwise human votes, style-controlled default view), higher is better	1,502 Claude Fable 5.1 (Max)	1,479 glm-5.3-max	15 Oct 2026
LMArena Text Arena: Creative Writing (style control) Arena score (Bradley-Terry rating from pairwise human votes, creative-writing prompts only, style-controlled view), higher is better	1,485 Claude Fable 5.1 (Max)	1,453 glm-5.3-max	15 Oct 2026
LMArena WebDev / Code Arena (overall) Arena score (Bradley-Terry rating from pairwise human votes on web-app generation), higher is better	1,742 Claude Fable 5.1 (Max)	1,622 GLM-5.3 (Max)	18 Oct 2026
SWE-Bench Pro V2 (public set, full) Resolve rate on 642 validated long-horizon tasks from 11 copyleft repositories, re-graded on a pristine image under a locked offline protocol, higher is better	99.1% Fable 5.1 (Claude Code) high	95.6% GLM-5.3 (mini-swe-agent) max	19 Oct 2026