AI API receipt · BerriAI/litellm

Concurrent /v1/messages calls sometimes answer 500 "dictionary changed size during iteration" while the spend row records success

BerriAI/litellm#44748 · upstream bug reproduced by running the issue's own reproduction

✓ Badgr rejects this response

The provider answered and the spend row landed as a success, but the caller received a 500 with no message.

Outcome contract verdict: response is empty. The attempt is recorded as failed (invalid_outcome) instead of a verified success, so it is not billed as a good answer and can fall back to another route.

What the upstream returned (replayed)

The output the bug produces, taken from the issue’s reproduction and fed to Badgr’s validators. Not a live provider call.

text: none
tool_calls: none

Badgr receipt

Written by Badgr’s receipt ledger and read back from GET /v1/receipts/replay-litellm-44748-500-while-spend-records-success.

{
  "request_id": "replay-litellm-44748-500-while-spend-records-success",
  "status": "failed",
  "endpoint": "/v1/chat/completions",
  "stream": false,
  "failure_stage": "outcome_contract",
  "error_code": "invalid_outcome",
  "error_message": "Response did not satisfy the outcome contract: response is empty",
  "retryable": true,
  "provider_mode": "replay",
  "routing_decision": "replayed_upstream_output",
  "created_at": "1791543162.32357"
}

Recorded 2026-10-09 in Badgr’s local development environment. Replay cases and verdicts are pinned by backend/test_ai_api_replay_cases.py.

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