[BOT ISSUE] xAI: add missing `grok-4.20-multi-agent-0309` primary model ID

[github-actions]

Gap

The xAI model grok-4.20-multi-agent-0309 (the primary/canonical model ID) is missing from packages/proxy/schema/model_list.json. The catalog has the beta alias grok-4.20-multi-agent-beta-0309 but not the primary non-beta ID — which is how xAI now lists this model on their official docs. This follows the pattern of other grok-4.20 models in the catalog where both beta and non-beta IDs have separate entries (e.g., grok-4.20-beta-0309-reasoning and grok-4.20-0309-reasoning both exist).

Official sources

Field	Source	URL
Model ID, listing, pricing	xAI Models page	https://docs.x.ai/developers/models
Model ID, pricing, aliases, capabilities, regions	xAI Model detail page	https://docs.x.ai/developers/models/grok-4.20-multi-agent-0309

Verified fields

• Model ID: grok-4.20-multi-agent-0309 — confirmed as the primary identifier on both pages
• Aliases: grok-4.20-multi-agent, grok-4.20-multi-agent-latest, grok-4.20-multi-agent-beta-latest, grok-4.20-multi-agent-experimental-beta-0304, grok-4.20-multi-agent-experimental-beta-latest, grok-4.20-multi-agent-beta-0309 — all confirmed on model detail page
• Format: openai — xAI uses OpenAI-compatible API format (same as all other grok models in catalog)
• Flavor: chat
• Multimodal: true — text and image input → text output (confirmed on model detail page)
• Input cost: $1.25 / 1M tokens — confirmed on both models page and model detail page
• Output cost: $2.50 / 1M tokens — confirmed on both pages
• Cached input cost: $0.20 / 1M tokens — confirmed on model detail page
• Reasoning: true — listed as a capability on model detail page
• Context window (max_input_tokens): 1000000 — confirmed on model detail page (1,000,000 tokens)
• Available providers: ["xAI"]

Fields NOT published

• max_output_tokens: Not specified on model detail page. Should be omitted or left for manual review.
• displayName: Not officially published; suggest "Grok 4.20 Multi-Agent (0309)" based on naming pattern.

Comparison with existing catalog entry

The catalog has grok-4.20-multi-agent-beta-0309 with pricing $2.00/$6.00, which differs from the xAI official pricing of $1.25/$2.50. The beta entry may also need a pricing update, but that is a separate issue (cost update, not missing model).

Local files inspected

• packages/proxy/schema/model_list.json — grep for grok-4.20-multi returns only grok-4.20-multi-agent-beta-0309
• Existing pattern: the catalog has both grok-4.20-beta-0309-non-reasoning AND grok-4.20-0309-non-reasoning as separate entries, confirming the convention of listing both beta and non-beta IDs

Verification notes

• Cross-source: Model ID confirmed on (1) xAI models listing page and (2) xAI model detail page — two independent official signals
• Recent commits: grok-4.20-multi-agent-0309 not present in current model_list.json
• ID format: grok-4.20-multi-agent-0309 matches xAI convention (like grok-4.20-0309-reasoning, grok-4.20-0309-non-reasoning)
• No duplicate issue: No existing [BOT ISSUE] references grok-4.20-multi-agent-0309

{
  "kind": "missing_model",
  "provider": "xAI",
  "models": ["grok-4.20-multi-agent-0309"],
  "status": "active",
  "model_specs": {
    "grok-4.20-multi-agent-0309": {
      "format": "openai",
      "flavor": "chat",
      "multimodal": true,
      "input_cost_per_mil_tokens": 1.25,
      "output_cost_per_mil_tokens": 2.5,
      "input_cache_read_cost_per_mil_tokens": 0.2,
      "reasoning": true,
      "max_input_tokens": 1000000,
      "available_providers": ["xAI"]
    }
  },
  "source_urls": [
    "https://docs.x.ai/developers/models",
    "https://docs.x.ai/developers/models/grok-4.20-multi-agent-0309"
  ]
}

Summary: Add grok-4.20-multi-agent-0309 to the xAI section of the model catalog. All fields except max_output_tokens are verified from official sources. The existing grok-4.20-multi-agent-beta-0309 entry may also need a pricing update ($2/$6 → $1.25/$2.50) as a separate issue.

[github-actions]

Prepared catalog updates for grok-4.20-multi-agent-0309. Added models: grok-4.20-multi-agent-0309.

Verification sources: https://docs.x.ai/developers/models, https://docs.x.ai/developers/models/grok-4.20-multi-agent-0309
Verified metadata applied:

• grok-4.20-multi-agent-0309: format=openai, flavor=chat, max_input_tokens=1000000, max_output_tokens=not provided, pricing(input/output per 1M)=1.25/2.5, input_cache_read_cost_per_mil_tokens=0.2, providers=xAI, reasoning=true, multimodal=true

Opened #668 to apply the catalog update.