openai/openai-python · error · OpenAIError

The Bedrock `endpoint` must be either `mantle` or `runtime`.

Error message

The Bedrock `endpoint` must be either `mantle` or `runtime`.

What it means

The `bedrock()` provider constructor only accepts the endpoint names `mantle` or `runtime` (or None for auto-detection). Any other string, including case variants like `Mantle` or full URLs, is rejected immediately with OpenAIError before any client is built.

Source

Thrown at src/openai/providers/bedrock.py:399

def bedrock(
    *,
    endpoint: BedrockEndpoint | None = None,
    region: str | None = None,
    base_url: str | httpx2.URL | None | NotGiven = NOT_GIVEN,
    api_key: str | None | NotGiven = NOT_GIVEN,
    token_provider: BedrockTokenProvider | None = None,
    access_key_id: str | None = None,
    secret_access_key: str | None = None,
    session_token: str | None = None,
    profile: str | None = None,
    credential_provider: AwsCredentialsProvider | None = None,
) -> _Provider:
    """Configure the standard OpenAI client for Amazon Bedrock Mantle or Runtime."""

    if endpoint is not None and endpoint not in {"mantle", "runtime"}:
        raise OpenAIError("The Bedrock `endpoint` must be either `mantle` or `runtime`.")

    normalized_region = _normalize_optional_string(region)
    if region is not None and normalized_region is None:
        raise OpenAIError("The Bedrock AWS `region` must not be empty.")
    _validate_bedrock_region(normalized_region)

    region_source: Literal["explicit", "environment"] | None = "explicit" if normalized_region is not None else None

    configured_base_url: httpx2.URL | None
    if isinstance(base_url, NotGiven):
        environment_base_url = _normalize_optional_string(os.environ.get("AWS_BEDROCK_BASE_URL"))
        configured_base_url = _normalize_base_url(environment_base_url) if environment_base_url else None
    elif base_url is None:
        configured_base_url = None
    else:
        if isinstance(base_url, str) and not base_url.strip():
            raise OpenAIError("The Bedrock `base_url` must not be empty.")
        configured_base_url = _normalize_base_url(base_url)

View on GitHub (pinned to 9917c6e28e)

Solutions

1. Set endpoint to exactly 'mantle' or 'runtime', or omit it to let the provider infer from base_url
2. Pass full hostnames via base_url instead of endpoint

Example fix

// before
bedrock(endpoint='bedrock-runtime')
// after
bedrock(endpoint='runtime')

if endpoint is not None and endpoint not in {'mantle', 'runtime'}:
    raise ValueError('endpoint must be mantle or runtime')

from typing import Literal

def is_bedrock_endpoint(v: object) -> bool:
    return v in ('mantle', 'runtime')

try:
    bedrock(endpoint=endpoint)
except OpenAIError as e:
    if 'endpoint' in str(e):
        # fall back to auto-detection
        bedrock()

When it happens

Trigger: Calling `openai.providers.bedrock(endpoint='bedrock-runtime', ...)` or passing a hostname/URL such as 'https://bedrock-runtime.us-east-1.amazonaws.com' as endpoint; also typos or wrong casing like 'Runtime'.

Common situations: Developers confuse the logical endpoint name with the AWS service hostname, or copy endpoint values from AWS docs instead of the SDK's `mantle`/`runtime` enum.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• The `api_key` argument must not be empty.
• Configure `provider` on `OpenAI`, not on `BedrockOpenAI.with
• Configure `provider` on `AsyncOpenAI`, not on `AsyncBedrockO
• The Bedrock {canonical_family} hostname does not match the s
• The Bedrock bearer credential provider must return a non-emp

AI-assisted analysis of openai/openai-python@9917c6e28e (2026-08-28). Data as JSON: /api/errors/600017e43ebe5f8f. Report an issue: GitHub.