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Anthropic · Language model

Claude Sonnet 5

anthropic/claude-sonnet-5
  • Language
Released Jun 30, 2026

Sonnet 5 is Anthropic's most capable Sonnet-class model, with frontier performance across coding, agents, and professional work. It supports adaptive thinking with selectable reasoning effort levels (low, medium, high, max,...

Specifications

Context window
1,000,000 tokens
Max output
128,000 tokens
Input
text, image, file
Output
text
Reasoning effort
max, xhigh, high, medium, low
Tokenizer
Claude
Moderation
provider-moderated

Supported parameters

Accepted by the model and forwarded as-is by the gateway.

  • max_completion_tokens
  • max_tokens
  • reasoning
  • reasoning_effort
  • response_format
  • stop
  • structured_outputs
  • tool_choice
  • tools
  • verbosity

Use it

POST /api/v1/chat/completions · MCP chat · full reference

curl https://omnirail.org/api/v1/chat/completions \
  -H "Authorization: Bearer $OMNIRAIL_KEY" -H "Content-Type: application/json" \
  -d '{"model":"anthropic/claude-sonnet-5","messages":[{"role":"user","content":"Hello"}],"max_tokens":300}'