Anthropic · 01 Sept 2026

Claude Fable 5.1

Anthropic’s Fable 5.1 update appears in Claude’s first-party release notes and model documentation.

ImpactMajor

High-signal launch with broad capability, access or platform-level implications.

ContextunknownAccessAPIWeightsclosedPriceunknownCheckConfirmed

Availability

StatusGAChannelAPIWeightsClosedPricingUnclearDocsLinked

Source qualityProduct changelog

Release is backed by first-party product or API change documentation.

Strong source · 3 receipts

Change Lens

What actually changed.

Normalized from the release note so different labs can be compared by the same fields, not just by launch copy.

Compared withClaude Fable 5

Fable 5.1 is listed as the current Fable release in first-party Claude release notes and model documentation.

CapabilityFable 5.1 is listed as the current Fable release in first-party Claude release notes and model documentation.changed

AvailabilityAvailable through Claude and Anthropic platform surfaces according to first-party Claude documentation.new

PricingNo pricing change found in the indexed note.unknown

ContextNo context-window change found in the indexed note.unknown

EvidenceClaude release notes · Claude Fable page · Claude model docsnew

ConfidenceConfirmed

Evidence is first-party; comparison labels are normalized by Radar.

Source qualityProduct changelog

Release is backed by first-party product or API change documentation.

Strong source · 3 receipts

Source receipts

The Radar keeps claims traceable: first-party sources, normalized fields, unknowns and the latest verification marker used for this page.

Announcement01 Sept 2026

AvailabilityAvailable through Claude and Anthropic platform surfaces according to first-party Claude documentation.

PricingNo pricing change found in the indexed note.

ContextNo context-window change found in the indexed note.

ConfidenceConfirmed

Last checked05 Sept 2026

Needs review

Pricing, Context are not clearly specified in the indexed source note.

Why it matters

Updates the tracked Claude frontier tier with canonical release-note and model-doc evidence instead of relying on the older Fable 5 entry.

Capabilities

GeneralCodingMultimodal

Source

This brief links back to the first-party announcement or documentation used by the radar.