All tasks / Comparisons

Claude Fable 5.1 vs GPT-6 Astra

Compared only on public benchmark results, across the 10 tasks where both are listed: Claude Fable 5.1 is a tier higher in 3 of 10 shared tasks, GPT-6 Astra in 3, they share a tier in 2.

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

GPT-6 Astra

OpenAI's most capable GPT tier, introduced with GPT-6, aimed at complex reasoning and coding.

Vendor: OpenAI
Weights: Closed: API and apps only
Released: 3 Sep 2026
API price: $10 in / $50 out per 1M tokens
License: proprietary
Last verified: 18 Oct 2026

Alternatives to GPT-6 Astra

Task by task

Task	Claude Fable 5.1	GPT-6 Astra	Higher tier
Chat & assistants Models	S1,502 on LMArena Text Arena (overall, style control) · Cloud	A1,477 on LMArena Text Arena (overall, style control) · Cloud	Claude Fable 5.1
Search & research Models	S1,233 on LMArena Search Arena (style control) · Cloud	S1,246 on LMArena Search Arena (style control) · Cloud	Same tier
Writing Models	S1,485 on LMArena Text Arena: Creative Writing (style control) · Cloud	A1,450 on LMArena Text Arena: Creative Writing (style control) · Cloud	Claude Fable 5.1
Documents & OCR Models	–No public result yet · Cloud	–No public result yet · Cloud	—
Coding Models	A1,742 on LMArena WebDev / Code Arena (overall) · Cloud	S1,776 on LMArena WebDev / Code Arena (overall) · Cloud	GPT-6 Astra
Image understanding Models	S1,286 on LMArena Vision Arena (overall, style control) · Cloud	S1,286 on LMArena Vision Arena (overall, style control) · Cloud	Same tier
Vector graphics & logos Models	C1,300 on Design Arena SVG · Cloud	B1,431 on Design Arena SVG · Cloud	GPT-6 Astra
Browser & computer agents Models	–No public result yet · Cloud	–No public result yet · Cloud	—
Workflow automation Models	C59.4% on AutomationBench-AA (Artificial Analysis) · Cloud	A68.5% on AutomationBench-AA (Artificial Analysis) · Cloud	GPT-6 Astra
Slides & presentations Models	S1,328 on Design Arena Python-PPTX Slides · Cloud	A1,246 on Design Arena Python-PPTX Slides · Cloud	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	GPT-6 Astra	Snapshot
Artificial Analysis Intelligence Index Composite index over Artificial Analysis' own evaluation suite, higher is better	53 Claude Fable 5.1 (Max, Default Fallback)	53 GPT-6 Astra (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)	68.5% GPT-6 Astra (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	1,246 GPT-6 Astra (xhigh)	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	1,431 GPT-6 Astra (xhigh)	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	2,173 gpt-6-astra	24 Sep 2026
LMArena Search Arena (style control) Arena score (Bradley-Terry rating from pairwise human votes on search-grounded answers, style-controlled view), higher is better	1,233 claude-fable-5.1-high	1,246 gpt-6-astra-max	13 Oct 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)	1,477 gpt-6-astra-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)	1,450 gpt-6-astra-max	15 Oct 2026
LMArena Vision Arena (overall, style control) Arena score (Bradley-Terry rating from pairwise human votes on image + text prompts, style-controlled view), higher is better	1,286 claude-fable-5.1-max	1,286 gpt-6-astra-max	9 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)	1,776 GPT-6 Astra (Max)	18 Oct 2026
ParseBench (models) Overall: mean of five rule-based dimension scores (tables, charts, content faithfulness, semantic formatting, visual grounding) on ~2,000 human-verified enterprise pages, higher is better	78.9% Anthropic Fable 5.1	70.7% OpenAI GPT-6 Astra (Reasoning Low)	9 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	96.9% GPT-6-Astra (Codex) high	19 Oct 2026