[Bug]: Errors while using VertexAI Claude models in Codex CLI

[ashaka-netapp]

Check for existing issues

• I have searched the existing issues and checked that my issue is not a duplicate.

What happened?

Encountering below errors while using VertexAI Claude models in Codex CLI

• Vertex_aiException BadRequestError -
  b'{"type":"error","error":{"type":"invalid_request_error","message":"messages: text content blocks must be non-
  empty"},"request_id":"req_vrtx_011CYZCM5xwFNPwMuJndurak"}'. Received Model Group=claude-sonnet-4.5\nAvailable Model Group
  Fallbacks=None","type":null,"param":null,"code":"400"}}

• Vertex_aiException BadRequestError - Failed to parse tool call arguments for tool 'shell' (Anthropic tool invoke). Error: Expecting ',' delimiter: line 1 column 99 (char 98).
  Arguments: {"command": ["bash","-lc","find /x/repos/playground -name 'messages.py' -type f"]\nReceived
  Messages= ....
  (Possibly, the nested quotes are causing truncation)

Validation and sanitization when translating requests between different providers’ APIs need to be strengthened.

Steps to Reproduce

1. Configure Codex CLI to use VertexAI Claude models and use prompts triggering tool calls

Relevant log output

What part of LiteLLM is this about?

Proxy

What LiteLLM version are you on ?

v.1.81.14

Twitter / LinkedIn details

No response

[ashaka-netapp]

Also, facing the same issues described in #19061 for VertexAI Claude models in Codex CLI