✓ PASS

tanstack-ai 1.4.0

truncation.text-stream · gemini

Requirements

Id	Level	Status	Evidence
cause-is-truncation	MUST	SATISFIED	finish.value=null (absent); truth.finish="length"; error.category="truncation"; structured.returned_as_success=false
text-reported	SHOULD	SATISFIED	text.value="Octopuses are the ultimate masters of disguise, utilizing a" (primary); truth.text="Octopuses are the ultimate masters of disguise, utilizing a"
usage-reported	SHOULD	SATISFIED	usage.output=12 (primary); truth.usage.output=12

What the provider sent

Finish: length
Raw finish: MAX_TOKENS
Text: Octopuses are the ultimate masters of disguise, utilizing a
Tool calls: []
Usage: { "alternatives": {}, "cached_input": null, "input": 22, "output": 12, "raw": { "candidatesTokenCount": 12, "promptTokenCount": 22, "promptTokensDetails": [ { "modality": "TEXT", "tokenCount": 22 } ], "serviceTier": "standard", "totalTokenCount": 34 }, "reasoning": null, "total": 34 }
Stream completed: true
Error: null

Wire excerpt

status: 200
content-type: text/event-stream
body (sse):
data: {"candidates": [{"content": {"parts": [{"text": "Octop"}],"role": "model"},"index": 0}],"usageMetadata": {"promptTokenCount": 22,"candidatesTokenCount": 2,"totalTokenCount": 24,"promptTokensDetails": [{"modality": "TEXT","tokenCount": 22}],"serviceTier": "standard"},"modelVersion": "gemini-3.5-flash-lite","responseId": "pgTOaonbKMuV_uMPvK7d4AE"}


data: {"candidates": [{"content": {"parts": [{"text": "uses are the ultimate masters of disguise, utilizing a"}],"role": "model"},"index": 0}],"usageMetadata": {"promptTokenCount": 22,"candidatesTokenCount": 12,"totalTokenCount": 34,"promptTokensDetails": [{"modality": "TEXT","tokenCount": 22}],"serviceTier": "standard"},"modelVersion": "gemini-3.5-flash-lite","responseId": "pgTOaonbKMuV_uMPvK7d4AE"}


data: {"candidates": [{"content": {"parts": [{"text": "","thoughtSignature": "EmAKXgFpFH0TZDFrxNfmg9AEtzn2/Lx2X7T4rX3Pufmp9MeuUeV6QQ4IEIffogLQkVUdgUWJ+G4L48EXf5L/wtPCbXTOk+KphherC1msoBUGh/7uYYFRDFon0XDRetF/fVo="}],"role": "model"},"finishReason": "MAX_TOKENS","index": 0}],"usageMetadata": {"promptTokenCount": 22,"candidatesTokenCount": 12,"totalTokenCount": 34,"promptTokensDetails": [{"modality": "TEXT","tokenCount": 22}],"serviceTier": "standard"},"modelVersion": "gemini-3.5-flash-lite","responseId": "pgTOaonbKMuV_uMPvK7d4AE"}

What the library reported

Outcome

returned

Finish

{
  "raw": null,
  "source": null,
  "surface": "absent",
  "value": null
}

Text

Value: Octopuses are the ultimate masters of disguise, utilizing a
Surface: primary

Tool calls

[]

Usage

{
  "cached_input": null,
  "input": 22,
  "output": 12,
  "reasoning": null,
  "surface": {
    "cached_input": "absent",
    "input": "primary",
    "output": "primary",
    "reasoning": "absent",
    "total": "primary"
  },
  "total": 34
}

Stream

{
  "chunks_seen": 6,
  "completed": false,
  "used": true
}

Error

Type: max_tokens
Message: The response was cut off because the maximum token limit was reached.
Category: truncation
Retry after: null
Stack top: null

Unsupported reason

null

Full observation JSON

{
  "elapsed_ms": 132.5453990000001,
  "error": {
    "category": "truncation",
    "message": "The response was cut off because the maximum token limit was reached.",
    "retry_after": null,
    "stack_top": null,
    "type": "max_tokens"
  },
  "finish": {
    "raw": null,
    "source": null,
    "surface": "absent",
    "value": null
  },
  "format": "wiretruth.observation/v1",
  "library": {
    "api": "chat",
    "language": "javascript",
    "name": "tanstack-ai",
    "version": "1.4.0"
  },
  "notes": [],
  "outcome": "returned",
  "stream": {
    "chunks_seen": 6,
    "completed": false,
    "used": true
  },
  "structured": {
    "attempted": false,
    "returned_as_success": false,
    "value": null
  },
  "text": {
    "surface": "primary",
    "value": "Octopuses are the ultimate masters of disguise, utilizing a"
  },
  "tool_calls": [],
  "unsupported_reason": null,
  "usage": {
    "cached_input": null,
    "input": 22,
    "output": 12,
    "reasoning": null,
    "surface": {
      "cached_input": "absent",
      "input": "primary",
      "output": "primary",
      "reasoning": "absent",
      "total": "primary"
    },
    "total": 34
  }
}

Fixture

recorded gemini/truncation.text-stream

Provenance	Value
Recorded at	2026-10-13T10:15:02Z
Requested model	gemini-3.5-flash-lite
Returned model	gemini-3.5-flash-lite
CI run	https://github.com/kartsan03/wiretruth/actions/runs/38381941285

Reproduce

wiretruth serve gemini/truncation.text-stream

Plain-library snippet from the shim manifest.

createGeminiChat(model, apiKey, { baseURL: WIRETRUTH_BASE_URL_GEMINI }); SDK appends /v1beta/models/<model>:streamGenerateContent or :generateContent.

Upstream

No matching upstream report.

History

Version	Grade
1.4.0	✓ PASS
1.0.0	✓ PASS
0.71.0	✓ PASS