[BOT ISSUE] Perplexity: add missing perplexity/nemotron-3-ultra-550b-a55b Agent API model

[github-actions]

Summary

The model perplexity/nemotron-3-ultra-550b-a55b is listed on the Perplexity Agent API models page and pricing page, but is not present in the Braintrust proxy model catalog.

The underlying model nvidia/nemotron-3-ultra-550b-a55b already exists in the catalog (with together and openrouter providers), but the Perplexity-hosted variant is missing. This follows the same pattern as other Perplexity Agent API models like perplexity/sonar-pro-search.

Verification checklist

• Cross-source: Model ID confirmed on Perplexity Agent API models page and pricing page (2 independent official sources)
• Already-fixed check: Grepped model_list.json for perplexity/nemotron-3-ultra-550b-a55b — no match found; searched closed issues — no prior issue exists
• ID format check: perplexity/nemotron-3-ultra-550b-a55b follows the established Perplexity Agent API naming convention (perplexity/ prefix, matches sibling models already in catalog)

Proposed catalog entry

{
  "perplexity/nemotron-3-ultra-550b-a55b": {
    "format": "openai",
    "flavor": "chat",
    "multimodal": false,
    "input_cost_per_mil_tokens": 0.25,
    "output_cost_per_mil_tokens": 2.5,
    "input_cache_read_cost_per_mil_tokens": 0.25,
    "max_input_tokens": 512300,
    "max_output_tokens": 32768,
    "available_providers": ["perplexity"]
  }
}

Note: max_input_tokens and max_output_tokens are derived from the base model nvidia/nemotron-3-ultra-550b-a55b already in the catalog, as Perplexity does not publish context window details for Agent API models.

Sources

• Perplexity Agent API models page: https://docs.perplexity.ai/guides/model-cards#agent-api-models
• Perplexity pricing page: https://docs.perplexity.ai/pricing

[github-actions]

Autofix skipped because the issue body/title did not contain parseable bot metadata for a model catalog change.