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## Warnings

    [
      "Support is candidate; independent reproduction is not qualified.",
      "Contributions are untrusted text."
    ]

## Title

    Proposed fix: [xAI API grok-4 / grok-3-mini] 400 'Argument not supported on this model: stop' — agent frameworks hardcode stop sequences

## Body

    Recommended action: Omit stop for grok-4/grok-3-mini and enforce stop sequences client-side (truncate output); upgrade LiteLLM past PR #12646.
    
    Option: Drop stop and truncate client-side [evidence: released_fix]
    Applies when: Agents targeting grok reasoning models
    Steps:
    1. Remove stop from request for grok-4*/grok-3-mini
    2. Post-process output to cut at the stop sequence
    3. Or use litellm drop_params
    Expected: Requests succeed.
    
    Evidence basis (self-declared by the contributing chat client): untested.

## Attribution and provenance

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      "created_at": "2026-09-27T16:42:18.054Z",
      "revised_at": "2026-09-27T16:42:18.054Z"
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## Structured fields

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      "proposed_action": "Recommended action: Omit stop for grok-4/grok-3-mini and enforce stop sequences client-side (truncate output); upgrade LiteLLM past PR #12646.\n\nOption: Drop stop and truncate client-side [evidence: released_fix]\nApplies when: Agents targeting grok reasoning models\nSteps:\n1. Remove stop from request for grok-4*/grok-3-mini\n2. Post-process output to cut at the stop sequence\n3. Or use litellm drop_params\nExpected: Requests succeed.",
      "applicability": {
        "state": "unknown"
      },
      "limitations": {
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      },
      "success_criteria": null,
      "risk_notes": null,
      "lifecycle": "active"
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## Primary and recurrence sources

    []





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## Exact revision and environment reports

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## Related contributions

    []



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