✓ PASS

tanstack-ai 1.4.0

stream.utf8-split · openai-chat

Requirements

Id	Level	Status	Evidence
text-reported	MUST	SATISFIED	text.value="Café Zürich — καλημέρα! 東京で会いましょう 🌸🎉" (primary); truth.text="Café Zürich — καλημέρα! 東京で会いましょう 🌸🎉"
no-replacement-chars	MUST	SATISFIED	text.value="Café Zürich — καλημέρα! 東京で会いましょう 🌸🎉" (primary); U+FFFD count=0

What the provider sent

Finish: stop
Raw finish: stop
Text: Café Zürich — καλημέρα! 東京で会いましょう 🌸🎉
Tool calls: []
Usage: { "alternatives": {}, "cached_input": null, "input": null, "output": null, "raw": null, "reasoning": null, "total": null }
Stream completed: true
Error: null

Wire excerpt

status: 200
content-type: text/event-stream; charset=utf-8
body (chunks_b64):
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What the library reported

Outcome

returned

Finish

{
  "raw": null,
  "source": "RUN_FINISHED.metadata.tanstack.finishReason",
  "surface": "primary",
  "value": "stop"
}

Text

Value: Café Zürich — καλημέρα! 東京で会いましょう 🌸🎉
Surface: primary

Tool calls

[]

Usage

{
  "cached_input": null,
  "input": null,
  "output": null,
  "reasoning": null,
  "surface": {
    "cached_input": "absent",
    "input": "absent",
    "output": "absent",
    "reasoning": "absent",
    "total": "absent"
  },
  "total": null
}

Stream

{
  "chunks_seen": 21,
  "completed": true,
  "used": true
}

Error

null

Unsupported reason

null

Full observation JSON

{
  "elapsed_ms": 99.70082400000001,
  "error": null,
  "finish": {
    "raw": null,
    "source": "RUN_FINISHED.metadata.tanstack.finishReason",
    "surface": "primary",
    "value": "stop"
  },
  "format": "wiretruth.observation/v1",
  "library": {
    "api": "chat",
    "language": "javascript",
    "name": "tanstack-ai",
    "version": "1.4.0"
  },
  "notes": [],
  "outcome": "returned",
  "stream": {
    "chunks_seen": 21,
    "completed": true,
    "used": true
  },
  "structured": {
    "attempted": false,
    "returned_as_success": false,
    "value": null
  },
  "text": {
    "surface": "primary",
    "value": "Café Zürich — καλημέρα! 東京で会いましょう 🌸🎉"
  },
  "tool_calls": [],
  "unsupported_reason": null,
  "usage": {
    "cached_input": null,
    "input": null,
    "output": null,
    "reasoning": null,
    "surface": {
      "cached_input": "absent",
      "input": "absent",
      "output": "absent",
      "reasoning": "absent",
      "total": "absent"
    },
    "total": null
  }
}

Fixture

derived openai-chat/stream.utf8-split

Provenance	Value
Transform	rechunk_inside_utf8
Source fixture	openai-chat/stream.utf8
Rationale	A network chunk boundary splits a multi-byte UTF-8 character.
Evidence	https://github.com/langchain-ai/langchainjs/issues/5285

Reproduce

wiretruth serve openai-chat/stream.utf8-split

Plain-library snippet from the shim manifest.

createOpenaiChatCompletions(model, apiKey, { baseURL: WIRETRUTH_BASE_URL_OPENAI_CHAT }); POST /v1/chat/completions. https://tanstack.com/ai/latest/docs/adapters/openai#chat-completions-api

Upstream

No matching upstream report.

History

Version	Grade
1.4.0	✓ PASS
1.0.0	✓ PASS
0.71.0	✓ PASS