fix: add Mistral models mistral-medium-2508 (#512)

fix: add Mistral models mistral-medium-2508

Closes #510

Source issue:
#510

**Summary**

| Field | Value |
| --- | --- |
| Provider | mistral |
| Primary model | mistral-medium-2508 |
| Changed models | `mistral-medium-2508` |
| Added models | `mistral-medium-2508` |
| Updated models | None |
| Verification sources |
[1](https://docs.mistral.ai/models/model-cards/mistral-medium-3-1-25-08)<br>[2](https://docs.mistral.ai/models/overview)
|

**Verified metadata**

| Model | Display name | Parent | Providers | Format | Flavor | Token
limits | Pricing | Lifecycle |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| mistral-medium-2508 | Mistral Medium 3.1 (2508) |
mistral-medium-latest | mistral | openai | chat | input=128000,
output=not provided | in/out=0.4/2 per 1M |
parent=mistral-medium-latest; multimodal=true |

**Verification notes**

_No LLM verification step ran — model metadata was already complete in
the issue._

**sync_models vs proposed update**

sync_models cross-check found differences. Official provider
verification was used for the applied values, and sync_models
discrepancies are listed below for review.

| Model | Field | Proposed update | sync_models | sync_models source
models |
| --- | --- | --- | --- | --- |
| mistral-medium-2508 | catalog entry | present | missing | None |

Co-authored-by: cpinn <4450689+cpinn@users.noreply.github.com>
Co-authored-by: Caitlin Pinn <caitlin.pinn@gmail.com>

Author: github-actions[bot]

packages/proxy/schema/index.ts

@@ -607,6 +607,7 @@ export const AvailableEndpointTypes: { [name: string]: ModelEndpointType[] } = {
   "grok-2-1212": ["xAI"],
   "grok-vision-beta": ["xAI"],
   "grok-beta": ["xAI"],
+  "mistral-medium-2508": ["mistral"],
   "deepseek-ai/DeepSeek-V4-Pro": ["together"],
   "Qwen/Qwen3.5-397B-A17B": ["together"],
   "accounts/fireworks/models/deepseek-v4-pro": ["fireworks"],

packages/proxy/schema/model_list.json

@@ -5297,6 +5297,19 @@
       "mistral"
     ]
   },
+  "mistral-medium-2508": {
+    "format": "openai",
+    "flavor": "chat",
+    "multimodal": true,
+    "input_cost_per_mil_tokens": 0.4,
+    "output_cost_per_mil_tokens": 2,
+    "displayName": "Mistral Medium (2508)",
+    "parent": "mistral-medium-latest",
+    "max_input_tokens": 128000,
+    "available_providers": [
+      "mistral"
+    ]
+  },
   "accounts/fireworks/models/kimi-k2p5": {
     "format": "openai",
     "flavor": "chat",