Model comparison

Claude Fable 5.1 vs Qwen 3.8 Max

Anthropic against Qwen, compared on context, price, and verified benchmark results.

Catalog record checked September 3, 2026Individual provider fields may changeEvidence confidence: High — see receipts below

Anthropic

Claude Fable 5.1

Frontier

Qwen

Qwen 3.8 Max

Frontier · Open weights

AI model capability comparison
Specification	Claude Fable 5.1	Qwen 3.8 Max
Provider	Anthropic	Qwen
Tier	Frontier	Frontier
Context window	Winner: 1M	991K
Max output	128K	Winner: 131K
Input / 1M tokens	$10	Winner: $2
Output / 1M tokens	$50	Winner: $6
Weights	Closed	Open
Parameters	Not disclosedUnverified	2.4T total / 95B active (MoE)
Reasoning levels	adaptive	low, high, max
Modalities	text, image	text, image, video
API model id	claude-fable-5-1	qwen3.8-max
Released	September 1, 2026	August 3, 2026
Artificial Analysis Intelligence Index (2026-08-14)	Winner: 66	58
Humanity's Last Exam (2026-09-01)	Winner: 65	56.2
Terminal-Bench 2.1 (2026-09-05)	Winner: 91.4	86.6
DeepSWE 1.1 (2026-09-03)	67.4	Not verifiedUnverified
GPQA Diamond (2026-08-03)	Not verifiedUnverified	92.6
SWE-bench Verified (2026-09-01)	Not verifiedUnverified	85.6

Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Bold indicates the better figure where one is objectively better. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.

Benchmark receipts

2026-09-05: Artificial Analysis Terminal-Bench v2.1 (independent, Terminus 2, max effort — current AA leader)Agentic terminal work: multi-step tasks executed in a sandboxed shell environment. Comparability: comparable with caveat — Scores across Terminal-Bench major versions (v1 vs v2) are NOT comparable; harness configuration (container, time limits) also shifts results.
2026-09-03: OpenAI GPT-6 Astra launch chart (independent cross-vendor; Fable 5.1 not on the official Datacurve leaderboard)Agentic software engineering: pass@1 on real repo tasks with reported cost per completed task. Comparability: directly comparable
2026-09-01: vals.ai SWE-bench Verified leaderboard (independent, mini-swe-agent bash-only); not published by Qwen (official used SWE-bench Pro 67.7)Real GitHub issue resolution: does the model's patch pass the hidden tests. Comparability: comparable with caveat — Post-audit vendor claims and pre-audit scores sit on different task trust levels; scaffolding (agent harness, compute budget) also dominates results. Never aggregate across scaffolds.
2026-09-01: Anthropic announcement comparison table (vendor, with tools; 60.9 no tools)Frontier-knowledge ceiling: extremely hard multi-domain questions written to be near-impossible without deep expertise. Comparability: comparable with caveat — Subset/tool configurations (text-only vs with-tools) differ between vendors and materially change scores; must match configuration to compare.
2026-08-14: Z.ai GLM-5.3 blog (independent Z.ai-run, with tools; Qwen official no-tools 43.6 — both preserved)Frontier-knowledge ceiling: extremely hard multi-domain questions written to be near-impossible without deep expertise. Comparability: comparable with caveat — Subset/tool configurations (text-only vs with-tools) differ between vendors and materially change scores; must match configuration to compare.
2026-08-14: Artificial AnalysisComposite index blending reasoning, knowledge, and coding evals into one 0–100 score. Comparability: directly comparable — AA occasionally rebaselines the index scale between snapshots — a score captured on one date is only comparable to same-snapshot scores (check measuredAt).
2026-08-03: Qwen official blog (vendor-run table)Agentic terminal work: multi-step tasks executed in a sandboxed shell environment. Comparability: comparable with caveat — Scores across Terminal-Bench major versions (v1 vs v2) are NOT comparable; harness configuration (container, time limits) also shifts results.

Pricing tiers: Claude Fable 5.1: Priced with Fable 5 at $10/$50 per MTok; cache reads cut 75% to $0.25/MTok. Adaptive thinking always on (default effort high); knowledge cutoff Jun 2026. Sibling Mythos 5.1 launched the same day. · Qwen 3.8 Max: $2/$6 per MTok (Alibaba Cloud Model Studio). Weights announced open, verify they have dropped.

FrontierRecord checked September 3, 2026

Claude Fable 5.1

Claude Fable 5.1 is Anthropic's September 2026 flagship refresh, debuting at the top of LiveBench and the Artificial Analysis Intelligence Index.

Best for

Frontier agents
Hardest reasoning work
Fable 5 workloads at the same price

Watch out

Early-life model: leaderboard position is from launch-week boards; recheck before committing spend.

FrontierOpen weightsRecord checked September 3, 2026

Qwen 3.8 Max

Qwen 3.8 Max is Alibaba's flagship — 2.4T MoE with 1M-class context, near frontier on the Intelligence Index.

Best for

Open-weight frontier work
Long-context
Multimodal

Watch out

Open weights dropped 2026-08-12 under a custom (non-Apache) licence with vision and 1M-context stripped from the open checkpoint — the open checkpoint is not the full API model. Verify the licence before commercial use.

When the cheaper one wins

Qwen 3.8 Max is cheaper on output at $6 per million tokens against $50 for Claude Fable 5.1 — about 8.3×. Use the cheaper tier for classification, extraction, summarisation, and any task where the expensive model’s extra score does not change the accepted output. The expensive one only pays if your hardest task actually fails on the cheap tier. These are standard-tier API rates, excluding batch and cache discounts.

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Evidence confidence: High

How strong and complete the evidence behind this comparison is — not a prediction of which model is better.

Pricing verified on both sides — Input and output rates are verified for both models.
4/5 core specs verified on both sides — Not published for at least one side: parameter count.
3 shared named benchmarks with differing scores — Measured on: Artificial Analysis Intelligence Index, Humanity's Last Exam, Terminal-Bench 2.1.
Verified within the last 90 days — Newest catalog check was 8 days ago.
Both models carry source citations — Each side has at least two catalog sources on record.

Source receipts

Each catalog figure was checked against the provider or an independent second source on the date shown.

Claude Fable 5.1: Anthropic pricing — Fable 5.1/Mythos 5.1 $10/$50 (accessed 2026-09-03)
Claude Fable 5.1: Anthropic models overview — Fable 5.1 (1M context, 128K output) (accessed 2026-09-03)
Claude Fable 5.1: Artificial Analysis — Fable 5.1 Intelligence Index 66 #1 (accessed 2026-09-01)
Qwen 3.8 Max: Qwen — Qwen 3.8 Max (accessed 2026-08-29)
Qwen 3.8 Max: Alibaba Cloud Model Studio (accessed 2026-08-29)

Related comparisons

Diving deeper on one model? Claude Fable 5.1 · Qwen 3.8 Max

Common questions

Claude Fable 5.1 vs Qwen 3.8 Max

Answered from the verified figures on this page rather than general guidance.

Is Claude Fable 5.1 or Qwen 3.8 Max cheaper for input?

Qwen 3.8 Max is cheaper at $2 per million input tokens, against $10 for Claude Fable 5.1 — roughly 5.0× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; Claude Fable 5.1 has tiered pricing: Priced with Fable 5 at $10/$50 per MTok; cache reads cut 75% to $0.25/MTok. Adaptive thinking always on (default effort high); knowledge cutoff Jun 2026. Sibling Mythos 5.1 launched the same day. Qwen 3.8 Max has tiered pricing: $2/$6 per MTok (Alibaba Cloud Model Studio). Weights announced open, verify they have dropped.

Is Claude Fable 5.1 or Qwen 3.8 Max cheaper for output?

Qwen 3.8 Max is cheaper at $6 per million output tokens, against $50 for Claude Fable 5.1 — roughly 8.3× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; Claude Fable 5.1 has tiered pricing: Priced with Fable 5 at $10/$50 per MTok; cache reads cut 75% to $0.25/MTok. Adaptive thinking always on (default effort high); knowledge cutoff Jun 2026. Sibling Mythos 5.1 launched the same day. Qwen 3.8 Max has tiered pricing: $2/$6 per MTok (Alibaba Cloud Model Studio). Weights announced open, verify they have dropped.

Which has the larger context window, Claude Fable 5.1 or Qwen 3.8 Max?

Claude Fable 5.1 accepts 1M tokens against 991K for Qwen 3.8 Max. This only matters if you routinely send very long documents or large codebases.

Do Claude Fable 5.1 and Qwen 3.8 Max support the same reasoning levels?

Claude Fable 5.1 exposes adaptive, while Qwen 3.8 Max exposes low, high, max.

Should I use Claude Fable 5.1 or Qwen 3.8 Max?

Both sit in the frontier tier, so the choice usually comes down to price and context rather than capability. Claude Fable 5.1 suits frontier agents; Qwen 3.8 Max suits open-weight frontier work.

Can I self-host Claude Fable 5.1 or Qwen 3.8 Max?

Qwen 3.8 Max publishes open weights, but self-hosting and third-party provider access depend on the licence, hardware, serving support, and availability. Claude Fable 5.1 is a closed model whose supported access paths are controlled by its provider.

Next step

Choosing between them

The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.

Input price: Qwen 3.8 Max costs $2 per 1M tokens versus $10 for Claude Fable 5.1 — a 5x difference at the headline tier.
Context: Claude Fable 5.1 takes 1M against 991K for Qwen 3.8 Max — only decisive if your prompts approach the smaller window.
Measured capability: Claude Fable 5.1 leads Artificial Analysis Intelligence Index 66 to 58 (measured 2026-08-14).
Deployment: Qwen 3.8 Max publishes weights you can self-host; the other is API-only.

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