Model comparison

Claude Fable 5.1 vs Mistral Large 3

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

Catalog record checked September 5, 2026Individual provider fields may changeEvidence confidence: High — see receipts below

Anthropic

Claude Fable 5.1

Frontier

Mistral

Mistral Large 3

Frontier · Open weights

AI model capability comparison
Specification	Claude Fable 5.1	Mistral Large 3
Provider	Anthropic	Mistral
Tier	Frontier	Frontier
Context window	Winner: 1M	262K
Max output	128K	Winner: 262K
Input / 1M tokens	$10	Winner: $0.50
Output / 1M tokens	$50	Winner: $1.50
Weights	Closed	Open
Parameters	Not disclosedUnverified	675B total / 41B active (sparse MoE)
Reasoning levels	adaptive	Not verifiedUnverified
Modalities	text, image	text, image
License	Not disclosedUnverified	Apache 2.0
API model id	claude-fable-5-1	mistral-large-3
Released	September 1, 2026	December 1, 2025
Artificial Analysis Intelligence Index (2026-08-14)	Winner: 66	46
Humanity's Last Exam (2026-09-01)	65	Not verifiedUnverified
Terminal-Bench 2.1 (2026-09-05)	91.4	Not verifiedUnverified
DeepSWE 1.1 (2026-09-03)	67.4	Not verifiedUnverified
GPQA Diamond (2025-12-02)	Not verifiedUnverified	43.9

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: 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: 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).
2025-12-02: Mistral — Introducing Mistral 3 (vendor, base model, 5-shot no CoT); independent review concursGraduate-level science reasoning: multiple-choice questions written by domain PhDs. Comparability: comparable with caveat — Small question pool: differences under ~2 points are within run-to-run noise. Chain-of-thought vs direct answering must match to compare.

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. · Mistral Large 3: Mistral first-party API $0.50/$1.50 per MTok; cached input $0.05/MTok. Open weights (Apache 2.0), EU-hosted.

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 5, 2026

Mistral Large 3

Mistral Large 3 is Mistral's flagship — 262K-context, multimodal, Apache-2.0 open-weight at $0.50/$1.50.

Best for

Open-weight deployments
Multimodal EU-hosted inference
Balanced frontier work

Watch out

Verify multimodal support and EU data-residency on your endpoint.

When the cheaper one wins

Mistral Large 3 is cheaper on output at $1.50 per million tokens against $50 for Claude Fable 5.1 — about 33×. 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.
3/5 core specs verified on both sides — Not published for at least one side: parameter count, reasoning levels.
1 shared named benchmark with differing scores — Measured on: Artificial Analysis Intelligence Index.
Verified within the last 90 days — Newest catalog check was 6 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)
Mistral Large 3: Mistral docs — mistral-large-2512 (675B total / 41B active, 256K) (accessed 2026-09-05)
Mistral Large 3: Mistral — Introducing Mistral 3 (sparse MoE parameters) (accessed 2026-09-05)

Related comparisons

Diving deeper on one model? Claude Fable 5.1 · Mistral Large 3

Common questions

Claude Fable 5.1 vs Mistral Large 3

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

Is Claude Fable 5.1 or Mistral Large 3 cheaper for input?

Mistral Large 3 is cheaper at $0.50 per million input tokens, against $10 for Claude Fable 5.1 — roughly 20× 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. Mistral Large 3 has tiered pricing: Mistral first-party API $0.50/$1.50 per MTok; cached input $0.05/MTok. Open weights (Apache 2.0), EU-hosted.

Is Claude Fable 5.1 or Mistral Large 3 cheaper for output?

Mistral Large 3 is cheaper at $1.50 per million output tokens, against $50 for Claude Fable 5.1 — roughly 33× 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. Mistral Large 3 has tiered pricing: Mistral first-party API $0.50/$1.50 per MTok; cached input $0.05/MTok. Open weights (Apache 2.0), EU-hosted.

Which has the larger context window, Claude Fable 5.1 or Mistral Large 3?

Claude Fable 5.1 accepts 1M tokens against 262K for Mistral Large 3. This only matters if you routinely send very long documents or large codebases.

Should I use Claude Fable 5.1 or Mistral Large 3?

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; Mistral Large 3 suits open-weight deployments.

Can I self-host Claude Fable 5.1 or Mistral Large 3?

Mistral Large 3 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: Mistral Large 3 costs $0.50 per 1M tokens versus $10 for Claude Fable 5.1 — a 20x difference at the headline tier.
Context: Claude Fable 5.1 takes 1M against 262K for Mistral Large 3 — only decisive if your prompts approach the smaller window.
Measured capability: Claude Fable 5.1 leads Artificial Analysis Intelligence Index 66 to 46 (measured 2026-08-14).
Deployment: Mistral Large 3 publishes weights you can self-host; the other is API-only.

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