[BOT ISSUE] Mistral: add missing mistral-medium-3-5-26-04 snapshot

[github-actions]

Summary

The dated snapshot mistral-medium-3-5-26-04 for Mistral Medium 3.5 is missing from the catalog. The alias entries mistral-medium-3.5 (line ~4772) and mistral-medium-latest (line ~4357) exist with correct pricing ($1.50/$7.50) and specs, but the specific snapshot — which users can pass to pin to the April 2026 release — has no catalog entry.

This was part of issue #505 (closed May 2026), which added the aliases mistral-medium-3.5 and mistral-medium-3 but did not add the dated snapshot.

All other current Mistral models have both alias and snapshot entries:

• mistral-small-latest → mistral-small-2603 ✅
• mistral-large-latest → mistral-large-2512 ✅
• mistral-medium-latest → mistral-medium-3-5-26-04 ❌ missing

Missing Entry

Field	Value	Source
Model ID	mistral-medium-3-5-26-04	Mistral model card
Format	openai	Catalog convention for Mistral
Flavor	chat	Chat model
Multimodal	true	Model card: "frontier-class multimodal model"
Input pricing	$1.50 / MTok	Mistral model card
Output pricing	$7.50 / MTok	Mistral model card
Context window	256,000 tokens	Model card
Released	April 28, 2026	Model card

Verification

Check	Status	Detail
Cross-source (model existence)	✅	Models overview: lists Mistral Medium 3.5 with link to model card AND Mistral pricing: confirms $1.50/$7.50 pricing
Cross-source (snapshot ID)	✅	Model card page URL: snapshot ID in URL path AND Issue #505: previously identified this exact ID
Already fixed	✅	Confirmed mistral-medium-3-5-26-04 is absent from model_list.json
Alias entries exist	✅	mistral-medium-3.5 (line ~4772) and mistral-medium-latest (line ~4357) both present with correct pricing
ID format	✅	Follows Mistral's model-version-YYMM snapshot convention
Duplicate check	✅	Issue #505 (closed) covered this but snapshot was not added; no open issue covers it

Verification Notes

Field	Source	Notes
Snapshot ID mistral-medium-3-5-26-04	Model card page	Confirmed in URL and page content
Pricing $1.50/$7.50	Model card + pricing page	Matches existing alias entries
256K context	Model card	Matches existing alias entries

Additional Note

The existing mistral-medium-latest and mistral-medium-3.5 entries are missing reasoning: true and reasoning_budget: true flags. Mistral's documentation confirms Medium 3.5 supports the reasoning_effort parameter. This is a separate metadata concern from the missing snapshot.

Local Files Inspected

• packages/proxy/schema/model_list.json — confirmed mistral-medium-3-5-26-04 absent; mistral-medium-3.5 (line ~4772) and mistral-medium-latest (line ~4357) present with correct pricing

{
  "kind": "missing_model",
  "provider": "mistral",
  "models": ["mistral-medium-3-5-26-04"],
  "status": "active",
  "model_specs": {
    "mistral-medium-3-5-26-04": {
      "format": "openai",
      "flavor": "chat",
      "multimodal": true,
      "input_cost_per_mil_tokens": 1.5,
      "output_cost_per_mil_tokens": 7.5,
      "displayName": "Mistral Medium 3.5 (2026-04)",
      "parent": "mistral-medium-3.5",
      "max_input_tokens": 256000,
      "available_providers": ["mistral"]
    }
  },
  "source_urls": [
    "https://docs.mistral.ai/models/model-cards/mistral-medium-3-5-26-04",
    "https://docs.mistral.ai/getting-started/models",
    "https://mistral.ai/pricing"
  ]
}

[github-actions]

Prepared catalog updates for mistral-medium-3-5-26-04. Added models: mistral-medium-3-5-26-04.

Verification sources: https://docs.mistral.ai/models/model-cards/mistral-medium-3-5-26-04, https://docs.mistral.ai/getting-started/models, https://mistral.ai/pricing, #505
Verified metadata applied:

• mistral-medium-3-5-26-04: format=openai, flavor=chat, displayName=Mistral Medium 3.5 (2026-04), parent=mistral-medium-3.5, max_input_tokens=256000, max_output_tokens=not provided, pricing(input/output per 1M)=1.5/7.5, providers=mistral, multimodal=true

Included in the daily batch PR: #904