Anthropic

Claude Fable 5.1

anthropic/claude-fable-5.1
Released Sep 1, 2026Commercial
ThinkingToolsVisioncommercial cloud

Claude Fable 5.1 improves on Claude Fable 5 across the board, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work: long code refactors, front-end and visual...

Cost / 1M tokens

Very high usage

$10.00

input

$0.25

cached input

$50.00

output

Context Window

1M

Up to 128K max output

Modalities

text, image, file → text

Claude tokenizer

Quickstart & API

anthropic/claude-fable-5.1
Open the model picker in ChatOSS Desktop (Code, Kanban, or Chat) and select or paste this model ID.

Best for & Strengths

Key Strengths

Software engineeringAgentic codingReasoning

Recommended Workloads in ChatOSS

  • Large codebases
  • Professional development
  • Coding agents
Available in ChatOSS Code, Kanban Orchestrate, and Chat modes via Plus, Max, or BYOK.

Verified Evaluations

Benchmarks & Frontier Comparison

How Claude Fable 5.1 compares against leading open-weight and proprietary frontier models across independent agentic coding and reasoning suites.

View full Top 40 Leaderboard →
Claude Fable 5.1DeepSeek V4.1 FlashGLM 5.3Kimi K3.1 Pro
Benchmark (Metric)Claude Fable 5.1DeepSeek V4.1 FlashGLM 5.3Kimi K3.1 ProClaude Opus 5.5
Agentic & Software Engineering
ChatOSS Agentic Coding Index (%)67.6%63.2%58.3%65%74.1%
SWE-Bench Verified (%)95%91.5%95.4%94.8%97%
DeepSWE v1.1 (Pass@1 %)67.4%77%69%73.5%74.2%
Vibe Code Bench v1.1 (%)90.26%87.7%78.1%88.4%90.3%
Terminal-Bench 4.0 (%)58.08%42.3%42%46.2%65.2%
Code Migration (%)54.61%45.6%44.2%52%66.7%
Intelligence & Token Economics
Artificial Analysis Intelligence Index (0–100)5039.544.855.157.6
Input Price (/ 1M tokens)$10.00$0.15$1.40$2.00$4.00
Output Price (/ 1M tokens)$50.00$0.60$4.40$10.00$20.00

ChatOSS Agentic Coding Index

ChatOSS Benchmark Audit · 4-benchmark composite mean

67.6%

SWE-Bench Verified

Vals AI · Terminus 2

95%

DeepSWE v1.1

DeepSWE / Official Audit · Mini-SWE-Agent

67.4%

Vibe Code Bench v1.1

Vals.ai · OpenHands

90.26%

Terminal-Bench 4.0

Vals.ai / Artificial Analysis · Terminus 2

58.08%

Terminal-Bench 2.1

Vals.ai · Terminus 2

80.52%

Code Migration

Vals.ai · Vals evaluation harness

54.61%

Artificial Analysis Intelligence Index

Artificial Analysis

50

Design Arena: FULLSTACK

Design Arena · Rank #3 (57.1% win)

1304 Elo

Design Arena: GODOTGAMEDEV

Design Arena · Rank #1 (60.7% win)

1327 Elo

Design Arena: HTMLSLIDES

Design Arena · Rank #1 (56.5% win)

1394 Elo

Design Arena: MOBILEAPPS

Design Arena · Rank #8 (56.3% win)

1257 Elo

Active Provider Endpoints (5)

Upstream inference providers serving Claude Fable 5.1, with per-provider pricing, context limits, quantization, and 24-hour uptime.

ProviderInput / 1MOutput / 1MCache Read / 1MContextMax OutputQuantizationUptime (24h)
Azure
azure
$10.00$50.00$0.251M128K—99.7%
Anthropic
anthropic
$10.00$50.00$0.251M128K—99.6%
Amazon Bedrock
amazon-bedrock
$10.00$50.00$0.251M128K——
Google
google-vertex/global
$10.00$50.00$0.251M128K—100.0%
Google
google-vertex/us
$11.00$55.00$0.2751M128K—100.0%

Supported API Parameters

Parameters accepted by this model when called through ChatOSS or OpenRouter.

include_reasoningmax_completion_tokensmax_tokensreasoningreasoning_effortresponse_formatstopstructured_outputstool_choicetoolsverbosity

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