docs: add Rapid-MLX as a custom AI endpoint

content/docs/configuration/librechat_yaml/ai_endpoints/meta.json

@@ -23,6 +23,7 @@
     "openrouter",
     "perplexity",
     "portkey",
+    "rapid-mlx",
     "shuttleai",
     "togetherai",
     "truefoundry",

content/docs/configuration/librechat_yaml/ai_endpoints/rapid-mlx.mdx

@@ -0,0 +1,34 @@
+---
+title: Rapid-MLX
+description: Configure Rapid-MLX as a custom endpoint in LibreChat.
+---
+
+[Rapid-MLX](https://rapidmlx.com) is an Apple-Silicon-native inference server (pure MLX) that serves models locally through an OpenAI-compatible API, so you can point LibreChat at your own Mac.
+
+Install it with `brew install rapid-mlx` (or `pip install rapid-mlx`) and start a model with `rapid-mlx serve qwen3.5-4b-4bit --port 8000`. This pins the server to `http://localhost:8000`. Browse the model catalog at [models.rapidmlx.com](https://models.rapidmlx.com/).
+
+## Configuration
+
+By default, the local Rapid-MLX server does not require an API key, so the value below is a placeholder. Point `baseURL` at your running server and add the endpoint under `endpoints.custom` in your `librechat.yaml`:
+
+```yaml filename="librechat.yaml"
+    - name: "Rapid-MLX"
+      apiKey: "rapid-mlx"
+      baseURL: "http://localhost:8000/v1/"
+      models:
+        default: [
+          "qwen3.5-4b-4bit"
+          ]
+        fetch: false # list the model served by this instance explicitly
+      titleConvo: true
+      titleModel: "current_model"
+      summarize: false
+      summaryModel: "current_model"
+      modelDisplayLabel: "Rapid-MLX"
+```
+
+## Notes
+
+- Each server instance serves one model. For another model, start a second instance on another port and add an endpoint with its own `baseURL`.
+- If LibreChat runs in Docker on the same Mac, use `host.docker.internal` in place of `localhost` in `baseURL`.
+- Set `default` to the alias you launched (e.g. `qwen3.5-4b-4bit`). Any alias from the [Rapid-MLX catalog](https://models.rapidmlx.com/) works.