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Amazon Bedrock Mantle

Amazon Bedrock Mantle is Amazon Bedrock's distributed inference engine (Project Mantle) that exposes an OpenAI-compatible API for Bedrock-hosted models.

Use this provider to call Bedrock Mantle models with accurate AWS Bedrock pricing instead of OpenAI pricing.

tip

We support ALL Bedrock Mantle models, just set model=bedrock_mantle/<model-id> as a prefix when sending litellm requests

Claude Mythos​

Claude Mythos (anthropic.claude-mythos-preview) is available on Bedrock Mantle with 1M token input context, 128K output, and support for reasoning, vision, and tool use.

Use the bedrock_mantle/ route prefix with standard AWS credentials.

/messages​

import asyncio
import litellm
import os

os.environ['AWS_ACCESS_KEY_ID'] = "your-aws-access-key"
os.environ['AWS_SECRET_ACCESS_KEY'] = "your-aws-secret-key"
os.environ['AWS_REGION_NAME'] = "us-east-1"

async def main():
    response = await litellm.anthropic_messages(
        model="bedrock_mantle/anthropic.claude-mythos-preview",
        max_tokens=1024,
        messages=[{"role": "user", "content": "Explain quantum entanglement simply."}],
    )
    print(response)

asyncio.run(main())

/chat/completions​

from litellm import completion
import os

os.environ['AWS_ACCESS_KEY_ID'] = "your-aws-access-key"
os.environ['AWS_SECRET_ACCESS_KEY'] = "your-aws-secret-key"
os.environ['AWS_REGION_NAME'] = "us-east-1"

response = completion(
    model="bedrock_mantle/anthropic.claude-mythos-preview",
    messages=[{"role": "user", "content": "Explain quantum entanglement simply."}],
)
print(response)

Claude Models on /v1/messages​

Every bedrock_mantle/anthropic.claude-* model, Claude Mythos included, is served on /v1/messages from Bedrock Mantle's native Anthropic Messages endpoint, https://bedrock-mantle.{region}.api.aws/anthropic/v1/messages, rather than bridged through chat completions, which Mantle rejects for Claude models. This is the surface Claude Code and the Anthropic SDKs talk to, and LiteLLM forwards the request in Anthropic's own wire format, so streaming, tools, and thinking pass straight through. Other Mantle models, the GPT models below for example, keep using the Responses API bridge on /v1/messages

Use the bare Mantle model id, such as bedrock_mantle/anthropic.claude-sonnet-5 or bedrock_mantle/anthropic.claude-haiku-4-5. A us. inference-profile prefix returns a 404 from Mantle

import asyncio
import litellm
import os

os.environ['AWS_ACCESS_KEY_ID'] = "your-aws-access-key"
os.environ['AWS_SECRET_ACCESS_KEY'] = "your-aws-secret-key"
os.environ['AWS_REGION_NAME'] = "us-east-2"

async def main():
    response = await litellm.anthropic_messages(
        model="bedrock_mantle/anthropic.claude-sonnet-5",
        max_tokens=1024,
        messages=[{"role": "user", "content": "Explain quantum entanglement simply."}],
    )
    print(response)

asyncio.run(main())

The region comes from aws_region_name, else a region prefix in the model name (bedrock_mantle/us-east-2/anthropic.claude-sonnet-5), else the host of api_base or BEDROCK_MANTLE_API_BASE when it points at Mantle, else BEDROCK_MANTLE_REGION, AWS_REGION_NAME, or AWS_REGION, and finally us-east-1. A custom api_base (a VPC endpoint or a proxy in front of Mantle) is kept as the host and /anthropic/v1/messages is appended to it, whether it was configured with or without an /openai/v1 or /v1 suffix

Auth is the same chain as the rest of the provider: a bearer token from api_key, BEDROCK_MANTLE_API_KEY, or AWS_BEARER_TOKEN_BEDROCK when one is set, otherwise SigV4 from aws_access_key_id / aws_secret_access_key / aws_session_token, aws_profile_name, or the role params. LiteLLM sends anthropic-version: 2023-06-01 on every request, and an anthropic-version header supplied by the caller wins

Beta features travel in the anthropic-beta header: the values the caller sends plus the ones a request needs (a context_management edit adds context-management-2025-06-27), limited to what Mantle accepts. A value Mantle does not know is left out instead of failing the request with a 400, and nothing is sent in the body anthropic_beta field, which Mantle ignores whenever the header is present

OpenAI Models (GPT-5.4 / GPT-5.5)​

/responses​

import litellm
import os

os.environ['BEDROCK_MANTLE_API_KEY'] = "your-bedrock-api-key"
os.environ['BEDROCK_MANTLE_REGION'] = "us-east-2"

response = litellm.responses(
    model="bedrock_mantle/openai.gpt-5.6-terra",
    input="Hello! How can you help me today?",
)
print(response)

Streaming​

import litellm
import os

os.environ['BEDROCK_MANTLE_API_KEY'] = "your-bedrock-api-key"

response = litellm.responses(
    model="bedrock_mantle/openai.gpt-5.6-terra",
    input="Tell me a three sentence bedtime story about a unicorn.",
    stream=True,
)

for event in response:
    print(event)

API Key​

# env variable
os.environ['BEDROCK_MANTLE_API_KEY'] = "your-aws-bedrock-api-key"

# optional: override region (defaults to us-east-1)
os.environ['BEDROCK_MANTLE_REGION'] = "us-east-1"  # or use AWS_REGION

Supported Models​

ModelEndpointContext WindowInput (per 1M tokens)Output (per 1M tokens)
openai.gpt-5.5/responses1.05M$5.50$33.00
openai.gpt-5.4/responses1.05M$2.75$16.50
openai.gpt-oss-120b/chat/completions131K$0.15$0.60
openai.gpt-oss-20b/chat/completions131K$0.07$0.30
openai.gpt-oss-safeguard-120b/chat/completions131K$0.15$0.60
openai.gpt-oss-safeguard-20b/chat/completions131K$0.07$0.20

Sample Usage​

from litellm import completion
import os

os.environ['BEDROCK_MANTLE_API_KEY'] = "your-bedrock-api-key"

response = completion(
    model="bedrock_mantle/openai.gpt-oss-120b",
    messages=[{"role": "user", "content": "hello from litellm"}],
)
print(response)

Region Configuration​

The API base URL is https://bedrock-mantle.{region}.api.aws/v1. Region is resolved in this order:

  1. aws_region_name on the deployment (or passed as a kwarg)
  2. A region prefix in the model name, e.g. bedrock_mantle/us-gov-west-1/xai.grok-4.3
  3. BEDROCK_MANTLE_REGION env var
  4. AWS_REGION_NAME env var, then AWS_REGION
  5. Default: us-east-1

An explicit api_base (or BEDROCK_MANTLE_API_BASE) replaces the derived URL entirely. The model-name prefix is stripped before the request is sent, so bedrock_mantle/us-gov-west-1/xai.grok-4.3 calls xai.grok-4.3 in us-gov-west-1; it is recognized for the regions LiteLLM knows for Bedrock, and aws_region_name works for every region. Claude models on /v1/messages use the /anthropic/v1/messages path instead of /v1 and keep a custom api_base as the host, see Claude Models on /v1/messages

Supported regions: us-east-1, us-east-2, us-west-2, eu-west-1, eu-west-2, eu-central-1, eu-south-1, eu-north-1, ap-northeast-1, ap-south-1, ap-southeast-3, sa-east-1, and us-gov-west-1 (AWS GovCloud)

import os
os.environ['BEDROCK_MANTLE_REGION'] = "eu-west-1"

# or pass api_base directly
response = completion(
    model="bedrock_mantle/openai.gpt-oss-120b",
    messages=[{"role": "user", "content": "hello"}],
    api_base="https://bedrock-mantle.eu-west-1.api.aws/v1",
)

GovCloud pricing​

Cost tracking uses the served region. When the price map has a row for bedrock_mantle/{region}/{model} (today the us-gov-west-1 rows), that row prices the call instead of the commercial one, whether the region came from aws_region_name or from the model prefix. Both of these deployments bill xai.grok-4.3 at the GovCloud rate:

model_list:
  - model_name: grok-4.3-gov
    litellm_params:
      model: bedrock_mantle/xai.grok-4.3
      aws_region_name: us-gov-west-1
      aws_access_key_id: os.environ/AWS_GOV_ACCESS_KEY_ID
      aws_secret_access_key: os.environ/AWS_GOV_SECRET_ACCESS_KEY
  - model_name: grok-4.3-gov-prefixed
    litellm_params:
      model: bedrock_mantle/us-gov-west-1/xai.grok-4.3
      aws_access_key_id: os.environ/AWS_GOV_ACCESS_KEY_ID
      aws_secret_access_key: os.environ/AWS_GOV_SECRET_ACCESS_KEY

A deployment that sets base_model or its own input_cost_per_token / output_cost_per_token is priced from that row alone; the served region is not applied on top of it

Usage with LiteLLM Proxy​

1. Set Bedrock Mantle models on config.yaml​

model_list:
  - model_name: gpt-5.5-mantle
    litellm_params:
      model: bedrock_mantle/openai.gpt-5.6-terra
      api_key: os.environ/BEDROCK_MANTLE_API_KEY
      api_base: "https://bedrock-mantle.us-east-2.api.aws/v1"

  - model_name: gpt-oss-120b
    litellm_params:
      model: bedrock_mantle/openai.gpt-oss-120b
      api_key: os.environ/BEDROCK_MANTLE_API_KEY
      # optional region override:
      api_base: "https://bedrock-mantle.us-east-1.api.aws/v1"

  - model_name: gpt-oss-20b
    litellm_params:
      model: bedrock_mantle/openai.gpt-oss-20b
      api_key: os.environ/BEDROCK_MANTLE_API_KEY

2. Start the proxy​

litellm --config /path/to/config.yaml

3. Send a request​

import openai

client = openai.OpenAI(
    api_key="anything",
    base_url="http://0.0.0.0:4000",
)

response = client.chat.completions.create(
    model="gpt-oss-120b",
    messages=[{"role": "user", "content": "hello from litellm"}],
)
print(response)
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