Claude Sonnet 4.5

anthropic/claude-sonnet-4.5

A chat model with a 1M-token context window, at $3.15 per million input tokens and $15.75 per million output tokens.

Details

Maker: anthropic
Kind: Chat
Context window: 1,000,000 tokens
Max output: 64,000 tokens
Input: $3.15 per million tokens
Cached input: $0.315 per million tokens, 90% off
Cache write: $3.9375 per million tokens
Output: $15.75 per million tokens
Capabilities: Reasoning, tool use, vision, file input, web search
Takes: Text, image, pdf
Returns: Text
Zero data retention: Yes, on every provider
No training on requests: Yes, on every provider
Released: 2025-09-29
Newer model: anthropic/claude-haiku-5.5Released later by the same maker, costs no more, and lists the same capabilities. Compare the two

Description

Claude Sonnet 4.5 is the newest model in the Sonnet series, offering improvements and updates over Sonnet 4.

Call it

curl

curl https://phantom.codes/v1/chat/completions \
  -H "Authorization: Bearer $PHANTOM_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "anthropic/claude-sonnet-4.5",
    "messages": [
      {"role": "user", "content": "Hello"}
    ]
  }'

Set PHANTOM_KEY to your key. Any OpenAI client works with the base URL https://phantom.codes/v1.

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