Skip to contentx402 is live on Robinhood Chain: agents can now pay for any model, per call, in USDG →
OmniRail
← All models

Anthropic · Language model

Claude Opus 4.8

anthropic/claude-opus-4.8
  • Language
Released May 27, 2026

Claude Opus 4.8 is Anthropic's most capable generally available model in the Opus family. It supports text, image, and file inputs with text output, with reasoning support and a 1M-token...

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
  • temperature
  • 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-opus-4.8","messages":[{"role":"user","content":"Hello"}],"max_tokens":300}'