Day 0 Support: Claude Sonnet 5.5

LiteLLM now supports Claude Sonnet 5.5 on Day 0. Use it across Anthropic, Bedrock, Gemini Enterprise Agent Platform, and Azure through the LiteLLM AI Gateway, with spend, rate limits, and logging in one place.

What's new in Sonnet 5.5

• Same price as Sonnet 5: $2 / MTok input, $10 / MTok output, $0.20 / MTok cache reads
• 30%+ faster, and up to 30% less per task, per Anthropic
• 70.6% on Terminal-Bench 4.0, up from Sonnet 5's 10.3%
• 1M-token context, up to 128K output tokens

Enabling Sonnet 5.5

Pricing landed in PR #43586. No upgrade needed: open Price Data under Models + Endpoints in the UI and click Reload Price Data (or POST /reload/model_cost_map), on v1.76.0 and above.

Usage

Anthropic

1. Setup config.yaml

model_list:
  - model_name: claude-sonnet-5-5
    litellm_params:
      model: anthropic/claude-sonnet-5-5
      api_key: os.environ/ANTHROPIC_API_KEY

2. Start the proxy

docker run -d \
  -p 4000:4000 \
  -e ANTHROPIC_API_KEY=$ANTHROPIC_API_KEY \
  -v $(pwd)/config.yaml:/app/config.yaml \
  ghcr.io/berriai/litellm:v1.103.0 \
  --config /app/config.yaml

Bedrock

1. Setup config.yaml

model_list:
  - model_name: claude-sonnet-5-5
    litellm_params:
      model: bedrock/anthropic.claude-sonnet-5-5
      aws_access_key_id: os.environ/AWS_ACCESS_KEY_ID
      aws_secret_access_key: os.environ/AWS_SECRET_ACCESS_KEY
      aws_region_name: us-east-1

note

For cross-region routing, use a regional inference profile such as bedrock/converse/us.anthropic.claude-sonnet-5-5. Regional profiles carry a 10% premium and global. stays at base price; LiteLLM tracks each variant.

2. Start the proxy

docker run -d \
  -p 4000:4000 \
  -e AWS_ACCESS_KEY_ID=$AWS_ACCESS_KEY_ID \
  -e AWS_SECRET_ACCESS_KEY=$AWS_SECRET_ACCESS_KEY \
  -v $(pwd)/config.yaml:/app/config.yaml \
  ghcr.io/berriai/litellm:v1.103.0 \
  --config /app/config.yaml

Gemini Enterprise Agent Platform

1. Setup config.yaml

model_list:
  - model_name: claude-sonnet-5-5
    litellm_params:
      model: vertex_ai/claude-sonnet-5-5
      vertex_project: os.environ/VERTEX_PROJECT
      vertex_location: global

2. Start the proxy

docker run -d \
  -p 4000:4000 \
  -e VERTEX_PROJECT=$VERTEX_PROJECT \
  -e GOOGLE_APPLICATION_CREDENTIALS=/app/credentials.json \
  -v $(pwd)/config.yaml:/app/config.yaml \
  -v $(pwd)/credentials.json:/app/credentials.json \
  ghcr.io/berriai/litellm:v1.103.0 \
  --config /app/config.yaml

Azure

1. Setup config.yaml

model_list:
  - model_name: claude-sonnet-5-5
    litellm_params:
      model: azure_ai/claude-sonnet-5-5
      api_key: os.environ/AZURE_AI_API_KEY
      api_base: os.environ/AZURE_AI_API_BASE  # https://<resource>.services.ai.azure.com

2. Start the proxy

docker run -d \
  -p 4000:4000 \
  -e AZURE_AI_API_KEY=$AZURE_AI_API_KEY \
  -e AZURE_AI_API_BASE=$AZURE_AI_API_BASE \
  -v $(pwd)/config.yaml:/app/config.yaml \
  ghcr.io/berriai/litellm:v1.103.0 \
  --config /app/config.yaml

3. Test it!

curl --location 'http://0.0.0.0:4000/chat/completions' \
--header 'Content-Type: application/json' \
--header 'Authorization: Bearer $LITELLM_KEY' \
--data '{
  "model": "claude-sonnet-5-5",
  "messages": [
    {
      "role": "user",
      "content": "what llm are you"
    }
  ]
}'

Worth knowing

Forced tool use returns a 400. Use tool_choice: "auto" and say in the prompt when the tool applies.

thinking: {"type": "disabled"} returns a 400. Anthropic's replacement is between_tools; see their migration guide.

Feedback

Running Claude Sonnet 5.5 through LiteLLM and hitting something unexpected? Share it on GitHub discussion #43590.