Python: Bug: Bedrock chat connector rejects OpenAI models (GPT-6 Sol/Luna/Astra, GPT-5.6, gpt-oss) with a model provider ValueError

[kimnamu]

Thanks to the Python team for the Bedrock connector (#9100) and the per-provider modules under model_provider/, which keep a new provider down to a few lines.

Describe the bug

BedrockChatCompletion can't call any OpenAI model on Bedrock. GPT-6 Sol and Luna (on Bedrock since 2026-09-22), GPT-6 Astra, GPT-5.6 and gpt-oss-120b fail before any request is sent because BedrockModelProvider has no openai member. Setting the provider doesn't help either: BEDROCK_MODEL_PROVIDER=openai fails validation.

case (main ca40aa7, live us-east-1, "Say pong.")	result
us.openai.gpt-6-sol, us.openai.gpt-6-luna, global.openai.gpt-6-sol, global.openai.gpt-6-luna	❌ ValueError: Model ID ... does not contain a valid model provider name.
us.openai.gpt-6-astra, global.openai.gpt-6-astra	❌ same ValueError
us.openai.gpt-5.6-sol, openai.gpt-oss-120b-1:0	❌ same ValueError
BEDROCK_MODEL_PROVIDER=openai (Sol and Astra)	❌ ServiceInitializationError <- Input should be 'ai21', 'amazon', 'anthropic', 'cohere', 'meta' or 'mistral'
model_provider=BedrockModelProvider.MISTRALAI (workaround attempt, Sol and Astra)	❌ ValidationException: This model doesn't support the stopSequences field.
us.anthropic.claude-haiku-4-5-20251001-v1:0	✅ 'pong'

Two causes:

• services/model_provider/bedrock_model_provider.py L24-43: the enum has ai21/amazon/anthropic/cohere/meta/mistral, and to_model_provider raises when none of them is in the model ID.
• services/bedrock_chat_completion.py L214 always sends "stopSequences": settings.stop. stop defaults to [] and remove_none_recursively only drops None, so every request carries stopSequences: []. Claude and Nova accept that, but the OpenAI models reject the field even when the list is empty (raw boto3 below).

To Reproduce

# AWS_DEFAULT_REGION=us-east-1 python repro.py us.openai.gpt-6-sol
import asyncio
import sys

from semantic_kernel.connectors.ai.bedrock import BedrockChatCompletion, BedrockChatPromptExecutionSettings
from semantic_kernel.contents import ChatHistory


async def main(model_id: str):
    svc = BedrockChatCompletion(model_id=model_id)
    history = ChatHistory()
    history.add_user_message("Say pong.")
    print(await svc.get_chat_message_content(history, BedrockChatPromptExecutionSettings()))


asyncio.run(main(sys.argv[1]))

  File "semantic_kernel/connectors/ai/bedrock/services/model_provider/bedrock_model_provider.py", line 43, in to_model_provider
    raise ValueError(f"Model ID {model_id} does not contain a valid model provider name.")
ValueError: Model ID us.openai.gpt-6-sol does not contain a valid model provider name.

Raw boto3 converse, "Say pong.", only inferenceConfig differs

us.openai.gpt-6-sol                           inferenceConfig={}                     OK ['pong']
us.openai.gpt-6-sol                           inferenceConfig={'stopSequences': []}  ERR This model doesn't support the stopSequences field. Remove stopSequences and try again.
us.openai.gpt-6-luna                          inferenceConfig={}                     OK ['pong']
us.openai.gpt-6-luna                          inferenceConfig={'stopSequences': []}  ERR This model doesn't support the stopSequences field. Remove stopSequences and try again.
us.openai.gpt-6-astra                         inferenceConfig={}                     OK ['pong']
us.openai.gpt-6-astra                         inferenceConfig={'stopSequences': []}  ERR This model doesn't support the stopSequences field. Remove stopSequences and try again.
global.openai.gpt-6-astra                     inferenceConfig={}                     OK ['pong']
global.openai.gpt-6-astra                     inferenceConfig={'stopSequences': []}  ERR This model doesn't support the stopSequences field. Remove stopSequences and try again.
us.openai.gpt-5.6-sol                         inferenceConfig={}                     OK ['pong']
us.openai.gpt-5.6-sol                         inferenceConfig={'stopSequences': []}  ERR This model doesn't support the stopSequences field. Remove stopSequences and try again.
openai.gpt-oss-120b-1:0                       inferenceConfig={}                     OK ['pong']
openai.gpt-oss-120b-1:0                       inferenceConfig={'stopSequences': []}  ERR This model doesn't support the stopSequences field. Remove stopSequences and try again.
us.anthropic.claude-haiku-4-5-20251001-v1:0   inferenceConfig={}                     OK ['Pong.']
us.anthropic.claude-haiku-4-5-20251001-v1:0   inferenceConfig={'stopSequences': []}  OK ['Pong.']
us.amazon.nova-lite-v1:0                      inferenceConfig={}                     OK ['Pong! ...']
us.amazon.nova-lite-v1:0                      inferenceConfig={'stopSequences': []}  OK ['Pong! ...']

Expected behavior

OpenAI model IDs route like the other providers. The patch in #14471 does it: an OPENAI enum value with a bedrock_openai.py that mirrors bedrock_mistralai.py, and stopSequences sent only when stop is set. GPT-6 Sol and Astra then pass plain, streaming, system prompt and tool calls (Auto, Required, streaming). Responses with a reasoningContent block (often on Luna, nearly always on gpt-oss, Sol and Astra on image/2-turn/short max_tokens prompts) also need #14469 (#14468).

Platform

• Language: Python
• Source: main branch (ca40aa7, 1.44.1)
• AI model: Bedrock us.openai.gpt-6-sol, us.openai.gpt-6-luna, global.openai.gpt-6-sol, global.openai.gpt-6-luna, us.openai.gpt-6-astra, global.openai.gpt-6-astra, us.openai.gpt-5.6-sol, openai.gpt-oss-120b-1:0
• IDE: none (script)
• OS: macOS

Additional context

• Bedrock OpenAI model parameters: https://docs.aws.amazon.com/bedrock/latest/userguide/model-parameters-openai.html