Implementation:BerriAI Litellm Anthropic Beta Headers Manager

Attribute	Value
Sources	litellm/anthropic_beta_headers_manager.py
Domains	Provider Integration, Anthropic, Headers, Configuration
last_updated	2026-02-15 16:00 GMT

Overview

The Anthropic Beta Headers Manager provides centralized filtering, transformation, and validation of Anthropic beta headers across multiple LLM providers (Anthropic, Bedrock, Vertex AI, Azure AI).

Description

Anthropic uses the anthropic-beta HTTP header to gate access to beta features. Different providers that expose Anthropic models (direct API, AWS Bedrock, Google Vertex AI, Azure AI) support different subsets of these headers and may use different header names. This module manages the mapping.

The configuration is loaded from a JSON file (anthropic_beta_headers_config.json) that maps each beta header to a provider-specific header name (or null if unsupported). Configuration can be fetched from:

• Remote URL (default) -- fetched from GitHub and cached in memory.
• Local file -- bundled with the package; used when LITELLM_LOCAL_ANTHROPIC_BETA_HEADERS=True.

Key classes and functions:

• GetAnthropicBetaHeadersConfig -- Static utility class for loading, fetching, and validating the configuration.
• filter_and_transform_beta_headers() -- The primary API: takes a list of beta header values and a provider name, returns only the supported headers with provider-specific names applied.
• update_headers_with_filtered_beta() -- Modifies a request headers dict in place, filtering the anthropic-beta header value.
• get_provider_name() -- Resolves provider aliases to canonical names.
• reload_beta_headers_config() -- Clears the cache and forces a fresh load.

Usage

Import the filtering functions when constructing requests to Anthropic-compatible providers:

from litellm.anthropic_beta_headers_manager import filter_and_transform_beta_headers

Code Reference

Source Location

/litellm/anthropic_beta_headers_manager.py (377 lines)

Key Functions

Function	Signature	Purpose
filter_and_transform_beta_headers	def filter_and_transform_beta_headers(beta_headers: List[str], provider: str) -> List[str]	Filters and maps beta headers for a specific provider
update_headers_with_filtered_beta	def update_headers_with_filtered_beta(headers: dict, provider: str) -> dict	Updates request headers dict in place
is_beta_header_supported	def is_beta_header_supported(beta_header: str, provider: str) -> bool	Checks if a specific header is supported
get_provider_beta_header	def get_provider_beta_header(anthropic_beta_header: str, provider: str) -> Optional[str]	Returns provider-specific header name
get_unsupported_headers	def get_unsupported_headers(provider: str) -> List[str]	Lists all unsupported headers for a provider
reload_beta_headers_config	def reload_beta_headers_config() -> Dict	Forces a cache refresh
get_beta_headers_config	def get_beta_headers_config(url: str) -> dict	Public entry point to load config (remote with local fallback)

Class: GetAnthropicBetaHeadersConfig

Method	Purpose
load_local_beta_headers_config()	Loads bundled JSON config from package resources
fetch_remote_beta_headers_config(url, timeout=5)	Fetches config from a remote URL via httpx
validate_beta_headers_config(fetched_config)	Validates that the config is a non-empty dict with provider keys

Import

from litellm.anthropic_beta_headers_manager import (
    filter_and_transform_beta_headers,
    update_headers_with_filtered_beta,
    is_beta_header_supported,
)

I/O Contract

Inputs

Parameter	Type	Description
beta_headers	List[str]	List of Anthropic beta header values (e.g., ["max-tokens-3-5-sonnet-2024-07-15"])
provider	str	Provider name (e.g., "anthropic", "bedrock", "vertex_ai")
headers	dict	Full request headers dictionary (for update_headers_with_filtered_beta)

Outputs

Return	Type	Description
Filtered headers	List[str]	Sorted list of provider-specific beta header values
Updated headers	dict	Modified request headers dict
Support check	bool	Whether a specific header is supported

Usage Examples

from litellm.anthropic_beta_headers_manager import (
    filter_and_transform_beta_headers,
    update_headers_with_filtered_beta,
)

# Filter beta headers for Bedrock
filtered = filter_and_transform_beta_headers(
    beta_headers=["max-tokens-3-5-sonnet-2024-07-15", "unsupported-feature"],
    provider="bedrock",
)
# Returns only headers supported by Bedrock with mapped names

# Update request headers in place
headers = {
    "anthropic-beta": "max-tokens-3-5-sonnet-2024-07-15,computer-use-2024-10-22",
    "content-type": "application/json",
}
update_headers_with_filtered_beta(headers, provider="vertex_ai")
# headers["anthropic-beta"] now contains only Vertex AI-supported values

Related Pages

• BerriAI_Litellm_Constants - defines ANTHROPIC_TOKEN_COUNTING_BETA_VERSION and related constants
• BerriAI_Litellm_Lazy_Imports_Registry - registers Anthropic config classes for lazy loading