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Python: Hosted Responses lose CostControl budget failure metadata #8487
Description
When a Foundry-hosted Agent Framework Responses agent receives a streaming model failure caused by a CostControl budget block, the raw model response includes x-ms-budget-cause: budget_exceeded and related budget headers. The OpenAI streaming SDK later raises a generic APIError from the SSE error event, and the hosting adapter currently emits a generic response.failed with error.code: server_error.
Expected behavior:
- Preserve the allowlisted CostControl response headers across the streaming exception boundary.
- Emit
response.failed.error.codeasbudget_exceeded. - Include compact CostControl details in response metadata so streaming and non-streaming Responses clients can render the correct budget-block experience.
The outer Responses HTTP status should remain protocol-compatible; this issue concerns the terminal failure body and metadata.
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[-]Hosted Responses lose CostControl budget failure metadata[/-][+]Python: Hosted Responses lose CostControl budget failure metadata[/+]github-actions commentedon Sep 18, 2026
🤖 Automated triage reproduction notes (agent-authored — trust but verify)
Agent analysis
Repro:
python/packages/foundry_hosting/agent_framework_foundry_hosting/_responses.py::ResponsesHostServer._emit_failureemits a generic failure when an exception carriesresponse_headerscontainingx-ms-budget-cause: budget_exceeded. Minimal repro: raise such an exception from an agentResponseStream, then POST to the Foundry Responses endpoint with eitherstream=Falseorstream=True; both return HTTP 200 witherror.code: server_errorand no CostControl metadata.python/packages/foundry_hosting/tests/test_responses.py1.0.0b260910eavanvalkenburg commentedon Oct 27, 2026
This looks worth considering in the MAF hosting integration. Darren Cohen (@dargilco), I have added you as an owner; could you have a look and advise on the appropriate scope?
We should keep this narrowly scoped to a safe, allowlisted budget-exhaustion classification and bounded metadata, preserving the existing sanitized public failures and Responses transport contract rather than exposing arbitrary exception bodies or headers.
For context, the earlier #8488 is closed unmerged, with outstanding feedback about retaining headers when Azure tracing wraps streaming responses, including the retrieve path. Azure/azure-sdk-for-python#49073 merged generic failure-metadata support, but selecting safe public fields and reliably carrying those headers through the adapter still need assessment. Please review those boundaries before we settle the implementation direction; this is consideration, not a commitment to implementation or timing.