docs: add TKBK custom endpoint example

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

@@ -25,6 +25,7 @@
     "perplexity",
     "portkey",
     "shuttleai",
+    "tkbk",
     "togetherai",
     "truefoundry",
     "vllm",

content/docs/configuration/librechat_yaml/ai_endpoints/tkbk.mdx

@@ -0,0 +1,54 @@
+---
+title: TKBK
+icon: Network
+description: Configure TKBK as a custom endpoint in LibreChat.
+---
+
+TKBK is an independent API gateway that serves Claude, GPT, Gemini, Grok, DeepSeek and GLM models with one API key, through an OpenAI-compatible endpoint and the native Anthropic Messages API. It is not affiliated with the model developers.
+
+## Get an API key
+
+Create a key at [tkbk.online/account](https://tkbk.online/account). Keys start with `cr_`. Add it to your `.env` file:
+
+```bash filename=".env"
+TKBK_API_KEY=cr_your-key-here
+```
+
+## Configuration
+
+Add the endpoints to the `custom` list under `endpoints` in your `librechat.yaml`. If your file already has an `endpoints.custom` list, paste only the `- name:` entries into it, keeping the same indentation.
+
+The first entry sends Claude models through the native Anthropic Messages API. The second entry serves every model in the catalog through the OpenAI-compatible endpoint and fetches the model list automatically.
+
+```yaml filename="librechat.yaml"
+endpoints:
+  custom:
+    - name: "TKBK Claude"
+      provider: "anthropic"
+      apiKey: "${TKBK_API_KEY}"
+      baseURL: "https://api.tkbk.online"
+      headers:
+        anthropic-version: "2023-06-01"
+      models:
+        default: ["claude-sonnet-5", "claude-opus-5-5", "claude-haiku-4-5"]
+        fetch: false
+      titleConvo: true
+      titleModel: "claude-haiku-4-5"
+      modelDisplayLabel: "TKBK Claude"
+    - name: "TKBK"
+      apiKey: "${TKBK_API_KEY}"
+      baseURL: "https://api.tkbk.online/v1"
+      models:
+        default: ["gpt-6.1-sol", "gemini-3.1-pro", "grok-4.7", "deepseek-v4-pro", "glm-5.3"]
+        fetch: true
+      titleConvo: true
+      titleModel: "deepseek-v4.1-flash"
+      modelDisplayLabel: "TKBK"
+```
+
+## Notes
+
+- For the `anthropic` provider, `baseURL` is the host without a path: LibreChat appends `/v1/messages` itself. Adding `/v1` there results in `404` errors.
+- Native Anthropic custom endpoints do not use `models.fetch`, so list the Claude models explicitly. The current model IDs are on [tkbk.online/models](https://tkbk.online/models) and in the machine-readable price list at [tkbk.online/pricing.json](https://tkbk.online/pricing.json).
+- With `fetch: true`, the OpenAI-compatible entry loads the model list from `GET https://api.tkbk.online/v1/models`. The `default` array is only the initial selection.
+- Usage is billed per token from the key's prepaid balance.