fix: redaction headers ignored when sent via proxy

[tsachis]

Summary

• Fix x-litellm-enable-message-redaction and litellm-enable-message-redaction headers being silently ignored when requests go through the proxy
• Add fallback in should_redact_message_logging() to read from metadata when litellm_metadata is None
• litellm-disable-message-redaction header is also fixed by this change

Root cause

get_litellm_params() always includes "litellm_metadata" as a key (even when None), so get_metadata_variable_name_from_kwargs() always returns "litellm_metadata". The redaction function then reads None instead of the actual metadata dict that contains the headers.

Fix

In should_redact_message_logging(), when the resolved metadata field is not a dict (i.e. None), fall back to litellm_params.get("metadata", {}).

Fixes #20739

Test plan

• Added 8 unit tests in tests/test_litellm/litellm_core_utils/test_redact_messages.py covering:
  • Enable redaction via x-litellm-enable-message-redaction header (proxy flow)
  • Enable redaction via litellm-enable-message-redaction header (proxy flow)
  • Disable redaction via litellm-disable-message-redaction header (proxy flow)
  • Headers in litellm_metadata (SDK direct call)
  • No headers defaults to global setting
  • Dynamic params precedence
• Existing tests pass: test_redact_msgs_from_logs, test_redact_msgs_from_logs_with_dynamic_params

🤖 Generated with Claude Code

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Project	Deployment	Actions	Updated (UTC)
litellm	Ready	Preview, Comment	Feb 9, 2026 1:41pm

[greptile-apps]

Greptile Overview

Greptile Summary

This PR fixes message-redaction headers being ignored in the proxy flow by updating should_redact_message_logging() to fall back to litellm_params["metadata"] when the resolved metadata field (often litellm_metadata) is present but not a dict (e.g., None). It also adds unit tests covering proxy vs SDK-direct metadata locations and precedence between dynamic params, headers, and global settings.

The change fits into the existing redaction decision path by ensuring request headers are actually read from the proxy-populated metadata structure, so the existing header-based enable/disable behavior works consistently across call paths.

Confidence Score: 4/5

• This PR is close to safe to merge, but there is a small correctness risk around non-dict metadata values causing runtime errors.
• The core fix is minimal and well-covered by unit tests, but the new fallback path can still leave metadata as a non-dict if litellm_params["metadata"] is also None/non-dict, which would make subsequent .get() calls crash in that edge case.
• litellm/litellm_core_utils/redact_messages.py

Important Files Changed

Filename	Overview
litellm/litellm_core_utils/redact_messages.py	Adds a fallback in should_redact_message_logging() to read headers from metadata when litellm_metadata is present but None, fixing proxy requests that previously ignored redaction headers.
tests/test_litellm/litellm_core_utils/test_redact_messages.py	Adds unit tests covering proxy vs SDK metadata locations and precedence between dynamic params, headers, and global setting for message redaction.

Sequence Diagram

sequenceDiagram
    participant Client
    participant Proxy as LiteLLM Proxy
    participant Redact as should_redact_message_logging

    Client->>Proxy: Request + headers
    Note over Proxy: Proxy builds model_call_details
    Proxy->>Redact: model_call_details
    Redact->>Redact: litellm_params = model_call_details["litellm_params"]
    Redact->>Redact: metadata_field = get_metadata_variable_name_from_kwargs(litellm_params)
    Redact->>Redact: metadata = litellm_params[metadata_field]
    alt metadata is dict
        Redact->>Redact: request_headers = metadata["headers"]
    else metadata is None/non-dict
        Note over Redact: Fix: fallback to litellm_params["metadata"]
        Redact->>Redact: metadata = litellm_params["metadata"]
        Redact->>Redact: request_headers = metadata["headers"]
    end
    Redact-->>Proxy: boolean (redact?)
    Proxy-->>Client: Response (logging redacted per decision)

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[greptile-apps]

_{2 files reviewed, 1 comment}

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[greptile-apps]

Non-dict metadata fallback
If litellm_params[metadata_field] is present but not a dict (e.g. None), the code falls back to litellm_params["metadata"] without re-validating it’s a dict. If metadata is also None/non-dict, metadata.get("headers") will raise. Consider normalizing after the fallback (e.g., metadata = metadata if isinstance(metadata, dict) else {}) so the function always handles non-dict inputs safely.

[tsachis]

Good catch! Fixed in 37f9bb7 — added a second isinstance check after the fallback so metadata is always normalized to {} when both fields are non-dict. Also added tests for the case where both litellm_metadata and metadata are None.

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