docs: expand minimax + cerebras setup

docs/gateway/configuration.md

@@ -1850,6 +1850,46 @@ Notes:
 - Available model: `MiniMax-M2.1` (default).
 - Update pricing in `models.json` if you need exact cost tracking.
 
+### Cerebras (GLM 4.6 / 4.7)
+
+Use Cerebras via their OpenAI-compatible endpoint:
+
+```json5
+{
+  env: { CEREBRAS_API_KEY: "sk-..." },
+  agents: {
+    defaults: {
+      model: {
+        primary: "cerebras/zai-glm-4.7",
+        fallbacks: ["cerebras/zai-glm-4.6"]
+      },
+      models: {
+        "cerebras/zai-glm-4.7": { alias: "GLM 4.7 (Cerebras)" },
+        "cerebras/zai-glm-4.6": { alias: "GLM 4.6 (Cerebras)" }
+      }
+    }
+  },
+  models: {
+    mode: "merge",
+    providers: {
+      cerebras: {
+        baseUrl: "https://api.cerebras.ai/v1",
+        apiKey: "${CEREBRAS_API_KEY}",
+        api: "openai-completions",
+        models: [
+          { id: "zai-glm-4.7", name: "GLM 4.7 (Cerebras)" },
+          { id: "zai-glm-4.6", name: "GLM 4.6 (Cerebras)" }
+        ]
+      }
+    }
+  }
+}
+```
+
+Notes:
+- Use `cerebras/zai-glm-4.7` for Cerebras; use `zai/glm-4.7` for Z.AI direct.
+- Set `CEREBRAS_API_KEY` in the environment or config.
+
 Notes:
 - Supported APIs: `openai-completions`, `openai-responses`, `anthropic-messages`,
   `google-generative-ai`