{"record":{"id":"72646675dbde4474","repo":"VectifyAI/PageIndex","slug":"the-model-returned-no-response","errorCode":null,"errorMessage":"The model returned no response.","messagePattern":"The model returned no response\\.","errorType":"exception","errorClass":"PageIndexAPIError","httpStatus":null,"severity":"error","filePath":"pageindex/local_chat.py","lineNumber":1109,"sourceCode":"\n    try:\n        turns = [turn for turn in runner]\n    except anthropic.AnthropicError as exc:\n        raise _model_backend_error(exc, \"messages\", client) from exc\n    except TypeError as exc:\n        # the SDK's request-time credential-resolution failure\n        if \"authentication\" not in str(exc).lower():\n            raise\n        raise PageIndexAPIError(\n            \"The Anthropic backend is not configured: set the \"\n            \"ANTHROPIC_API_KEY environment variable, or pass an \"\n            f\"api_key in chat_backend / backend. ({exc})\") from exc\n    finally:\n        # safe here: the params read-back below does no HTTP\n        if owns_transport:\n            backend_client.close()\n    if not turns:\n        raise PageIndexAPIError(\"The model returned no response.\")\n    captured: dict = {}\n\n    def capture(params):\n        captured.update(params)\n        return params\n\n    runner.set_messages_params(capture)\n    if not captured.get(\"messages\"):\n        # The conversation is read back through a mutator; if a vendor\n        # change stops it delivering params, the envelope would silently\n        # lose the tool turns — fail loudly instead.\n        raise PageIndexAPIError(\n            \"Could not read the conversation back from the anthropic tool \"\n            \"runner — the installed anthropic version is incompatible with \"\n            \"this pageindex release.\"\n        )\n    conversation = list(captured[\"messages\"])\n    final = turns[-1]","sourceCodeStart":1091,"sourceCodeEnd":1127,"githubUrl":"https://github.com/VectifyAI/PageIndex/blob/afb5e119766630af6014b04fe8b53357527bc05e/pageindex/local_chat.py#L1091-L1127","documentation":"After driving the Anthropic tool runner to completion, run_messages found zero turns recorded — the model never produced any assistant response the library could return. This is a server/model-side anomaly rather than a caller input problem.","triggerScenarios":"Calling client.messages(...) where the runner loop exits immediately without recording a turn (model returns an empty/aborted response, or an SDK edge case yields no events).","commonSituations":"A model outage or overloaded endpoint returning empty bodies; misconfigured backend pointing at a proxy that swallows responses; extremely rare vendor-side behavior.","solutions":["Retry the call — transient empty responses usually succeed on the next attempt","Inspect the backend/model name in chat_backend for typos or an unreachable base_url","If persistent, enable SDK-level logging to see the raw HTTP exchange"],"exampleFix":null,"handlingStrategy":"retry","validationCode":null,"typeGuard":null,"tryCatchPattern":"for attempt in range(3):\n    try:\n        return client.messages(prompt)\n    except PageIndexAPIError as e:\n        if 'no response' not in str(e) or attempt == 2:\n            raise\n        time.sleep(2 ** attempt)","preventionTips":["Retry with backoff on empty-model-response","Monitor for recurrence — persistent hits suggest backend misconfiguration"],"tags":["anthropic","empty-response","model","retry"],"backgroundTag":"empty-model-response","analyzedSha":"afb5e119766630af6014b04fe8b53357527bc05e","analyzedAt":"2026-08-27T11:20:48.519Z","schemaVersion":2},"datasetVersion":"2026-08-27T13:17:12.746Z"}