Anthropic: Claude Sonnet 5.5 Thinking

claude-sonnet-5.5:thinking

Claude Sonnet 5.5 with adaptive thinking for complex coding, multi-step tool use, visual analysis, and detailed planning. Supports a 1M-token context window and five reasoning effort levels, with stronger thinking available when a task needs it.

Modalities

Text + Image → Text

Input / output price

$2.60 / $13.00 per 1M

Context

1M · max output 128K

Capabilities

ReasoningVisionTool callingLong context

Pricing

Billed per token actually used and deducted from your credits.

ItemUSD per 1M tokens
Input$2.60
Output$13.00
Cached input$0.130

Calculator

Drag the sliders to estimate what this model will cost.

Per request
$0.0182
Per day
$9.10
Per month (30 days)
$273.00

Claude Sonnet 5.5 Thinking: input $2.6/M · output $13/M · cached input $0.13/M

Request with these settings
curl https://api.geniusrelaygpt.com/v1/chat/completions \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "claude-sonnet-5.5:thinking", "max_tokens": 800,
       "messages": [{"role": "user", "content": "…"}]}'

Code samples

OpenAI-compatible. Set the base URL to https://api.geniusrelaygpt.com/v1 and the model to claude-sonnet-5.5:thinking.

curl https://api.geniusrelaygpt.com/v1/chat/completions \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-5.5:thinking",
    "stream": true,
    "messages": [{"role": "user", "content": "Hello"}]
  }'

Use it in a client: Cursor · Cline · SillyTavern · Codex

Parameters

Common OpenAI parameters can be passed as-is.

temperaturetop_pmax_tokensstreamstoppresence_penaltyfrequency_penaltyseed

FAQ

How is Claude Sonnet 5.5 Thinking billed?
Input is $2.60 and output is $13.00 per million tokens; cached input is $0.130. The charge for every request is listed in Usage Logs in the console.
How long is the context window?
1M tokens. In a long conversation every turn is billed for the full input, so keep the history under control.
Does it support streaming?
Yes. Add "stream": true to the request to receive server-sent events in the OpenAI format.