Update: resolved by #538. The Databricks AI Gateway now serves the Codex dialect for the amazon_bedrock provider, so ucode codex --provider <bedrock-mps> reaches Bedrock end to end, verified against the live gateway. The original report is struck through below, kept for history.
Summary
Routing Codex to an Amazon Bedrock Model Provider Service through the Databricks AI Gateway does not work. The gateway serves the amazon_bedrock provider type only over Bedrock's native Converse API. Codex speaks the OpenAI Responses API, which the gateway rejects for Bedrock, so ucode codex --provider <bedrock-mps> cannot reach the provider and Codex falls back to its own picker (system-hosted OpenAI models).
Evidence
Tested against an amazon_bedrock MPS with the Databricks-Model-Provider-Service header set:
POST /ai-gateway/codex/v1/responses → INVALID_PARAMETER_VALUE: Native_api_type=openai/v1/responses is not supported for provider Amazon Bedrock.POST /ai-gateway/mlflow/v1/chat/completions → Native_api_type=mlflow/v1/chat/completions is not supported for provider Amazon Bedrock.POST /ai-gateway/model/{modelId}/converse and /converse-stream → work, returning real Bedrock output.
Declaring native_api_types on the MPS targets (for example openai/v1/responses) does not change this. The runtime still refuses non-Converse dialects for the amazon_bedrock provider, so that field is catalog metadata rather than a runtime switch.
Impact
Codex cannot use Amazon Bedrock through the gateway today.Pi and OpenCode are unaffected because they speak Converse. Pi support is in the follow-up PR.
Next steps
This is blocked on the gateway adding OpenAI Responses (or Chat) translation for the amazon_bedrock provider.Until that lands, ucode should not present Bedrock as a Codex provider, or should surface a clear "not supported" message instead of silently falling back.
SummaryRouting Codex to an Amazon Bedrock Model Provider Service through the Databricks AI Gateway does not work. The gateway serves theamazon_bedrockprovider type only over Bedrock's native Converse API. Codex speaks the OpenAI Responses API, which the gateway rejects for Bedrock, soucode codex --provider <bedrock-mps>cannot reach the provider and Codex falls back to its own picker (system-hosted OpenAI models).EvidenceTested against anamazon_bedrockMPS with theDatabricks-Model-Provider-Serviceheader set:POST /ai-gateway/codex/v1/responses→INVALID_PARAMETER_VALUE: Native_api_type=openai/v1/responses is not supported for provider Amazon Bedrock.POST /ai-gateway/mlflow/v1/chat/completions→Native_api_type=mlflow/v1/chat/completions is not supported for provider Amazon Bedrock.POST /ai-gateway/model/{modelId}/converseand/converse-stream→ work, returning real Bedrock output.Declaringnative_api_typeson the MPS targets (for exampleopenai/v1/responses) does not change this. The runtime still refuses non-Converse dialects for theamazon_bedrockprovider, so that field is catalog metadata rather than a runtime switch.ImpactCodex cannot use Amazon Bedrock through the gateway today.Pi and OpenCode are unaffected because they speak Converse. Pi support is in the follow-up PR.Next stepsThis is blocked on the gateway adding OpenAI Responses (or Chat) translation for theamazon_bedrockprovider.Until that lands, ucode should not present Bedrock as a Codex provider, or should surface a clear "not supported" message instead of silently falling back.