✓ PASS

pydantic-ai 2.61.0

stream.utf8-split · anthropic

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: end_turn
Text: Café Zürich — καλημέρα! 東京で会いましょう 🌸🎉
Tool calls: []
Usage: { "alternatives": {}, "cached_input": null, "input": 25, "output": 40, "raw": { "input_tokens": 25, "output_tokens": 40 }, "reasoning": null, "total": 65 }
Stream completed: true
Error: null

Wire excerpt

status: 200
content-type: text/event-stream
body (chunks_b64):
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
qSAifX0KCmV2ZW50OiBjb250ZW50X2Jsb2NrX2RlbHRhCmRhdGE6IHsidHlwZSI6ICJjb250ZW50X2Jsb2NrX2RlbHRhIiwgImluZGV4IjogMCwgImRlbHRhIjogeyJ0eXBlIjogInRleHRfZGVsdGEiLCAidGV4dCI6ICJaw7xyaWNoIOKAlCDO
us6xzrvOt868zq3Pgc6xISDm
nQ==
seS6rOOBp+S8muOBhOOBvuOBl+OCh+OBhiDw
nw==
jA==
uPCfjokifX0KCmV2ZW50OiBjb250ZW50X2Jsb2NrX3N0b3AKZGF0YTogeyJ0eXBlIjogImNvbnRlbnRfYmxvY2tfc3RvcCIsICJpbmRleCI6IDB9CgpldmVudDogbWVzc2FnZV9kZWx0YQpkYXRhOiB7InR5cGUiOiJtZXNzYWdlX2RlbHRhIiwiZGVsdGEiOnsic3RvcF9yZWFzb24iOiJlbmRfdHVybiIsInN0b3Bfc2VxdWVuY2UiOm51bGx9LCJ1c2FnZSI6eyJvdXRwdXRfdG9rZW5zIjo0MH19CgpldmVudDogbWVzc2FnZV9zdG9wCmRhdGE6IHsidHlwZSI6ICJtZXNzYWdlX3N0b3AifQoK

What the library reported

Outcome

returned

Finish

{
  "raw": "end_turn",
  "source": "ModelResponse.finish_reason",
  "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": 0,
  "input": 25,
  "output": 40,
  "reasoning": 0,
  "surface": {
    "cached_input": "primary",
    "input": "primary",
    "output": "primary",
    "reasoning": "primary",
    "total": "primary"
  },
  "total": 65
}

Stream

{
  "chunks_seen": 5,
  "completed": true,
  "used": true
}

Error

null

Unsupported reason

null

Full observation JSON

{
  "elapsed_ms": 233.0670515075326,
  "error": null,
  "finish": {
    "raw": "end_turn",
    "source": "ModelResponse.finish_reason",
    "surface": "primary",
    "value": "stop"
  },
  "format": "wiretruth.observation/v1",
  "library": {
    "api": "Agent.run_stream_events",
    "language": "python",
    "name": "pydantic-ai",
    "version": "2.61.0"
  },
  "notes": [],
  "outcome": "returned",
  "stream": {
    "chunks_seen": 5,
    "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": 0,
    "input": 25,
    "output": 40,
    "reasoning": 0,
    "surface": {
      "cached_input": "primary",
      "input": "primary",
      "output": "primary",
      "reasoning": "primary",
      "total": "primary"
    },
    "total": 65
  }
}

Fixture

derived anthropic/stream.utf8-split

Provenance	Value
Transform	rechunk_inside_utf8
Source fixture	anthropic/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 anthropic/stream.utf8-split

Plain-library snippet from the shim manifest.

AnthropicModel(model, provider=AnthropicProvider(base_url=WIRETRUTH_BASE_URL_ANTHROPIC, api_key=WIRETRUTH_API_KEY)); host root

Upstream

No matching upstream report.

History

Version	Grade
2.61.0	✓ PASS
2.56.0	✓ PASS