Improve Responses API input validation for multi-turn

[daniel-salib]

Purpose

Enhance the function_call_parsing validator to handle
common client
serialization variations when echoing previous
responses:

• Strip null/None values from input items before
  validation
• Auto-generate missing IDs for reasoning items
• Normalize output content types to input types in
  messages
• Handle both dict and Pydantic model inputs
  consistently

These changes make the API more robust when clients
send back
previous response items as input in multi-turn
conversations.

Test Plan

Inside codex prompt:

› refactor parse output msgs in vllm/entrypoints/
harmony_utils.py

Test Result

Server side:

^[[1;36m(APIServer pid=3168319)^[[0;0m WARNING 11-17 14:16:40 [protocol.py:126] The following fields were present in the request but ignored: {'prompt_cache_key'}
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO: 127.0.0.1:65258 - "POST /v1/responses HTTP/1.1" 200 OK
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:16:41 [loggers.py:236] Engine 000: Avg prompt throughput: 1560.3 tokens/s, Avg generation throughput: 120.1 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 4.5%, Prefix cache hit rate: 45.2%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:16:51 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 119.1 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 4.9%, Prefix cache hit rate: 45.2%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:17:01 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 117.1 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 5.2%, Prefix cache hit rate: 45.2%
^[[1;36m(APIServer pid=3168319)^[[0;0m WARNING 11-17 14:17:02 [protocol.py:126] The following fields were present in the request but ignored: {'prompt_cache_key'}
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO: 127.0.0.1:65258 - "POST /v1/responses HTTP/1.1" 200 OK
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:17:11 [loggers.py:236] Engine 000: Avg prompt throughput: 1815.9 tokens/s, Avg generation throughput: 112.4 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 5.5%, Prefix cache hit rate: 61.0%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:17:21 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 111.7 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 5.9%, Prefix cache hit rate: 61.0%
^[[1;36m(APIServer pid=3168319)^[[0;0m WARNING 11-17 14:17:24 [protocol.py:126] The following fields were present in the request but ignored: {'prompt_cache_key'}
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO: 127.0.0.1:65258 - "POST /v1/responses HTTP/1.1" 200 OK
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:17:31 [loggers.py:236] Engine 000: Avg prompt throughput: 2071.5 tokens/s, Avg generation throughput: 107.7 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 6.2%, Prefix cache hit rate: 69.2%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:17:41 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 109.1 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 6.5%, Prefix cache hit rate: 69.2%
^[[1;36m(APIServer pid=3168319)^[[0;0m WARNING 11-17 14:17:48 [protocol.py:126] The following fields were present in the request but ignored: {'prompt_cache_key'}
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO: 127.0.0.1:65258 - "POST /v1/responses HTTP/1.1" 200 OK
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:17:51 [loggers.py:236] Engine 000: Avg prompt throughput: 2329.3 tokens/s, Avg generation throughput: 105.1 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 6.8%, Prefix cache hit rate: 74.3%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:18:01 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 104.6 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 7.1%, Prefix cache hit rate: 74.3%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:18:11 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 103.2 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 7.4%, Prefix cache hit rate: 74.3%
^[[1;36m(APIServer pid=3168319)^[[0;0m WARNING 11-17 14:18:13 [protocol.py:126] The following fields were present in the request but ignored: {'prompt_cache_key'}
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO: 127.0.0.1:65258 - "POST /v1/responses HTTP/1.1" 200 OK
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:18:21 [loggers.py:236] Engine 000: Avg prompt throughput: 2586.4 tokens/s, Avg generation throughput: 98.3 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 7.7%, Prefix cache hit rate: 77.8%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:18:31 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 100.0 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 7.9%, Prefix cache hit rate: 77.8%
^[[1;36m(APIServer pid=3168319)^[[0;0m WARNING 11-17 14:18:39 [protocol.py:126] The following fields were present in the request but ignored: {'prompt_cache_key'}
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO: 127.0.0.1:65258 - "POST /v1/responses HTTP/1.1" 200 OK
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:18:41 [loggers.py:236] Engine 000: Avg prompt throughput: 2842.3 tokens/s, Avg generation throughput: 96.1 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 8.2%, Prefix cache hit rate: 80.4%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:18:51 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 97.4 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 8.5%, Prefix cache hit rate: 80.4%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:19:01 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 96.0 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 8.8%, Prefix cache hit rate: 80.4%
^[[1;36m(APIServer pid=3168319)^[[0;0m WARNING 11-17 14:19:06 [protocol.py:126] The following fields were present in the request but ignored: {'prompt_cache_key'}
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO: 127.0.0.1:65258 - "POST /v1/responses HTTP/1.1" 200 OK
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:19:11 [loggers.py:236] Engine 000: Avg prompt throughput: 3100.8 tokens/s, Avg generation throughput: 92.5 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 9.0%, Prefix cache hit rate: 82.3%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:19:21 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 93.3 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 9.3%, Prefix cache hit rate: 82.3%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:19:31 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 92.6 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 9.6%, Prefix cache hit rate: 82.3%
^[[1;36m(APIServer pid=3168319)^[[0;0m WARNING 11-17 14:19:34 [protocol.py:126] The following fields were present in the request but ignored: {'prompt_cache_key'}
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO: 127.0.0.1:65258 - "POST /v1/responses HTTP/1.1" 200 OK
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:19:41 [loggers.py:236] Engine 000: Avg prompt throughput: 3357.9 tokens/s, Avg generation throughput: 89.0 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 9.8%, Prefix cache hit rate: 83.9%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:19:51 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 89.5 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 10.1%, Prefix cache hit rate: 83.9%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:20:01 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 88.5 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 10.3%, Prefix cache hit rate: 83.9%
^[[1;36m(APIServer pid=3168319)^[[0;0m WARNING 11-17 14:20:03 [protocol.py:126] The following fields were present in the request but ignored: {'prompt_cache_key'}
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO: 127.0.0.1:65258 - "POST /v1/responses HTTP/1.1" 200 OK
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:20:11 [loggers.py:236] Engine 000: Avg prompt throughput: 3621.6 tokens/s, Avg generation throughput: 85.4 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 10.6%, Prefix cache hit rate: 85.2%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:20:21 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 85.8 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 10.8%, Prefix cache hit rate: 85.2%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:20:31 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 85.4 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 11.1%, Prefix cache hit rate: 85.2%
^[[1;36m(APIServer pid=3168319)^[[0;0m WARNING 11-17 14:20:34 [protocol.py:126] The following fields were present in the request but ignored: {'prompt_cache_key'}
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO: 127.0.0.1:65258 - "POST /v1/responses HTTP/1.1" 200 OK
^[[1;36m(APIServer pid=3168319)^[[0;0m WARNING 11-17 14:20:35 [protocol.py:126] The following fields were present in the request but ignored: {'prompt_cache_key'}
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO: 127.0.0.1:65258 - "POST /v1/responses HTTP/1.1" 200 OK
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:20:41 [loggers.py:236] Engine 000: Avg prompt throughput: 7771.6 tokens/s, Avg generation throughput: 81.9 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 11.3%, Prefix cache hit rate: 87.9%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:20:51 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 84.0 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 11.6%, Prefix cache hit rate: 87.9%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:21:01 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 83.0 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 11.8%, Prefix cache hit rate: 87.9%
^[[1;36m(APIServer pid=3168319)^[[0;0m WARNING 11-17 14:21:05 [protocol.py:126] The following fields were present in the request but ignored: {'prompt_cache_key'}
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO: 127.0.0.1:65258 - "POST /v1/responses HTTP/1.1" 200 OK
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:21:11 [loggers.py:236] Engine 000: Avg prompt throughput: 4147.6 tokens/s, Avg generation throughput: 80.1 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 12.0%, Prefix cache hit rate: 88.6%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:21:21 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 81.5 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 12.3%, Prefix cache hit rate: 88.6%
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:21:31 [loggers.py:236] Engine 000: Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 70.7 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 12.5%, Prefix cache hit rate: 88.6%
^[[1;36m(APIServer pid=3168319)^[[0;0m WARNING 11-17 14:21:40 [protocol.py:126] The following fields were present in the request but ignored: {'prompt_cache_key'}
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO: 127.0.0.1:65258 - "POST /v1/responses HTTP/1.1" 200 OK
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO 11-17 14:21:41 [loggers.py:236] Engine 000: Avg prompt throughput: 4421.2 tokens/s, Avg generation throughput: 76.6 tokens/s, Running: 1 reqs, Waiting: 0 reqs, GPU KV cache usage: 12.7%, Prefix cache hit rate: 89.2%
^[[1;36m(APIServer pid=3168319)^[[0;0m WARNING 11-17 14:21:42 [protocol.py:126] The following fields were present in the request but ignored: {'prompt_cache_key'}
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO: 127.0.0.1:65258 - "POST /v1/responses HTTP/1.1" 200 OK
^[[1;36m(APIServer pid=3168319)^[[0;0m WARNING 11-17 14:21:44 [protocol.py:126] The following fields were present in the request but ignored: {'prompt_cache_key'}
^[[1;36m(APIServer pid=3168319)^[[0;0m INFO: 127.0.0.1:65258 - "POST /v1/responses HTTP/1.1" 200 OK

Client side:

Implemented a comprehensive refactor of
parse_output_message in vllm/entrypoints/harmony_utils.py:

• Added detailed docstring and clarified.
  Streamlined assistant role handling and early for
  non‑assistant messages.
• Reorganized logic with clear sections browser actions,
  analysis, commentary, and final channels.
• Simplified JSON handling for browser calls with
  placeholder fallback.
• Utilized descriptive variable names and removed redundant
  comments.
• Consolidated output item creation for each channel type.
• Ensured consistent error handling for unknown channels
  or recipients.