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Models · Anthropic

Feature-frozen. The creator has frozen feature development on this model (critical fixes only).

Claude Sonnet 4.5

Model family: claude-sonnet-4

Claude Sonnet 4.5 — the prior recommended default with strong coding/agents, superseded by 4.6.

Identity

Creator
Anthropic
Model family
claude-sonnet-4
Release date
2025-09-28

Technical specs

Parameter count
The prior Sonnet default ($3/$15), known for strong coding and agent capabilities. 200K context (1M long-context billed separately). Superseded by 4.6.
Context window
200K tokens
Modalities
  • Image Input
  • Text
Primary capabilities
  • Chat
  • Coding
  • Instruction Following
  • Long Context
  • Reasoning
  • Tool Use
  • Vision

License

License
Anthropic Commercial Terms of Service
Commercial use
  • Allowed
Terms
  • Modification ✗
  • Redistribution ✗
  • Attribution ✗

Access

Openness
  • Closed Api
Access methods
  • Api First Party
  • Api Third Party
  • Hosted Chat Ui
Cost tier
  • Paid Api

Sources

Full model card →