Skip to main content
FluffBuzz includes a bundled Amazon Bedrock Mantle provider that connects to the Mantle OpenAI-compatible endpoint. Mantle hosts open-source and third-party models (GPT-OSS, Qwen, Kimi, GLM, and similar) through a standard /v1/chat/completions surface backed by Bedrock infrastructure.
PropertyValue
Provider IDamazon-bedrock-mantle
APIopenai-completions (OpenAI-compatible) or anthropic-messages (Anthropic Messages route)
AuthExplicit AWS_BEARER_TOKEN_BEDROCK or IAM credential-chain bearer-token generation
Default regionus-east-1 (override with AWS_REGION or AWS_DEFAULT_REGION)

​
Getting started

Choose your preferred auth method and follow the setup steps.
Best for: environments where you already have a Mantle bearer token.
1

Set the bearer token on the gateway host

export AWS_BEARER_TOKEN_BEDROCK="..."
Optionally set a region (defaults to us-east-1):
export AWS_REGION="us-west-2"
2

Verify models are discovered

fluffbuzz models list
Discovered models appear under the amazon-bedrock-mantle provider. No additional config is required unless you want to override defaults.

​
Automatic model discovery

When AWS_BEARER_TOKEN_BEDROCK is set, FluffBuzz uses it directly. Otherwise, FluffBuzz attempts to generate a Mantle bearer token from the AWS default credential chain. It then discovers available Mantle models by querying the region’s /v1/models endpoint.
BehaviorDetail
Discovery cacheResults cached for 1 hour
IAM token refreshHourly
The bearer token is the same AWS_BEARER_TOKEN_BEDROCK used by the standard Amazon Bedrock provider.

​
Supported regions

us-east-1, us-east-2, us-west-2, ap-northeast-1, ap-south-1, ap-southeast-3, eu-central-1, eu-west-1, eu-west-2, eu-south-1, eu-north-1, sa-east-1.

​
Manual configuration

If you prefer explicit config instead of auto-discovery: 
{
  models: {
    providers: {
      "amazon-bedrock-mantle": {
        baseUrl: "https://bedrock-mantle.us-east-1.api.aws/v1",
        api: "openai-completions",
        auth: "api-key",
        apiKey: "env:AWS_BEARER_TOKEN_BEDROCK",
        models: [
          {
            id: "gpt-oss-120b",
            name: "GPT-OSS 120B",
            reasoning: true,
            input: ["text"],
            cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
            contextWindow: 32000,
            maxTokens: 4096,
          },
        ],
      },
    },
  },
}

​
Advanced configuration

Reasoning support is inferred from model IDs containing patterns like thinking, reasoner, or gpt-oss-120b. FluffBuzz sets reasoning: true automatically for matching models during discovery.
If the Mantle endpoint is unavailable or returns no models, the provider is silently skipped. FluffBuzz does not error; other configured providers continue to work normally.
Mantle also exposes an Anthropic Messages route that carries Claude models through the same bearer-authenticated streaming path. Claude Opus 4.7 (amazon-bedrock-mantle/claude-opus-4.7) is callable through this route with provider-owned streaming, so AWS bearer tokens are not treated like Anthropic API keys.When you pin an Anthropic Messages model on the Mantle provider, FluffBuzz uses the anthropic-messages API surface instead of openai-completions for that model. Auth still comes from AWS_BEARER_TOKEN_BEDROCK (or the minted IAM bearer token).
{
  models: {
    providers: {
      "amazon-bedrock-mantle": {
        models: [
          {
            id: "claude-opus-4.7",
            name: "Claude Opus 4.7",
            api: "anthropic-messages",
            reasoning: true,
            input: ["text", "image"],
            contextWindow: 1000000,
            maxTokens: 32000,
          },
        ],
      },
    },
  },
}
Bedrock Mantle is a separate provider from the standard Amazon Bedrock provider. Mantle uses an OpenAI-compatible /v1 surface, while the standard Bedrock provider uses the native Bedrock API.Both providers share the same AWS_BEARER_TOKEN_BEDROCK credential when present.

Amazon Bedrock

Native Bedrock provider for Anthropic Claude, Titan, and other models.

Model selection

Choosing providers, model refs, and failover behavior.

OAuth and auth

Auth details and credential reuse rules.

Troubleshooting

Common issues and how to resolve them.