diff --git a/docs-site/src/content/docs/guides/providers.md b/docs-site/src/content/docs/guides/providers.md
index 24313e50a..835280d9f 100644
--- a/docs-site/src/content/docs/guides/providers.md
+++ b/docs-site/src/content/docs/guides/providers.md
@@ -291,6 +291,7 @@ free-experimentation model.
 | SiliconFlow | `https://api.siliconflow.cn/v1` |
 | Volcengine Ark · Coding Plan · Agent Plan | `https://ark.cn-beijing.volces.com/api/v3` · `https://ark.cn-beijing.volces.com/api/coding/v3` · `https://ark.cn-beijing.volces.com/api/plan/v3` |
 | Xiaomi MiMo | `https://api.xiaomimimo.com/anthropic` |
+| Xiaomi MiMo (OpenAI Chat) | `https://api.xiaomimimo.com/v1` |
 | Kilo | `https://api.kilo.ai/api/gateway` |
 | GitLab Duo | `https://cloud.gitlab.com/ai/v1/proxy/openai/v1` |
 | Cloudflare AI Gateway | `https://gateway.ai.cloudflare.com/v1/{account-id}/{gateway}/anthropic` |
diff --git a/docs-site/src/content/docs/ja/guides/providers.md b/docs-site/src/content/docs/ja/guides/providers.md
index 7a44f3a70..988bbfab7 100644
--- a/docs-site/src/content/docs/ja/guides/providers.md
+++ b/docs-site/src/content/docs/ja/guides/providers.md
@@ -218,6 +218,7 @@ Cline IDE/CLI のみで API からは使えません。`minimax/minimax-m2.5` 
 | SiliconFlow | `https://api.siliconflow.cn/v1` |
 | Volcengine Ark · Coding Plan · Agent Plan | `https://ark.cn-beijing.volces.com/api/v3` · `https://ark.cn-beijing.volces.com/api/coding/v3` · `https://ark.cn-beijing.volces.com/api/plan/v3` |
 | Xiaomi MiMo | `https://api.xiaomimimo.com/anthropic` |
+| Xiaomi MiMo (OpenAI Chat) | `https://api.xiaomimimo.com/v1` |
 | Kilo | `https://api.kilo.ai/api/gateway` |
 | GitLab Duo | `https://cloud.gitlab.com/ai/v1/proxy/openai/v1` |
 | Cloudflare AI Gateway | `https://gateway.ai.cloudflare.com/v1/{account-id}/{gateway}/anthropic` |
diff --git a/docs-site/src/content/docs/ko/guides/providers.md b/docs-site/src/content/docs/ko/guides/providers.md
index 0911820da..4d0e033d5 100644
--- a/docs-site/src/content/docs/ko/guides/providers.md
+++ b/docs-site/src/content/docs/ko/guides/providers.md
@@ -218,6 +218,7 @@ Cline IDE/CLI에서만 제공되며 API로는 사용할 수 없습니다. `minim
 | SiliconFlow | `https://api.siliconflow.cn/v1` |
 | Volcengine Ark · Coding Plan · Agent Plan | `https://ark.cn-beijing.volces.com/api/v3` · `https://ark.cn-beijing.volces.com/api/coding/v3` · `https://ark.cn-beijing.volces.com/api/plan/v3` |
 | Xiaomi MiMo | `https://api.xiaomimimo.com/anthropic` |
+| Xiaomi MiMo (OpenAI Chat) | `https://api.xiaomimimo.com/v1` |
 | Kilo | `https://api.kilo.ai/api/gateway` |
 | GitLab Duo | `https://cloud.gitlab.com/ai/v1/proxy/openai/v1` |
 | Cloudflare AI Gateway | `https://gateway.ai.cloudflare.com/v1/{account-id}/{gateway}/anthropic` |
diff --git a/docs-site/src/content/docs/ru/guides/providers.md b/docs-site/src/content/docs/ru/guides/providers.md
index 5b2e67a45..e2cb648c3 100644
--- a/docs-site/src/content/docs/ru/guides/providers.md
+++ b/docs-site/src/content/docs/ru/guides/providers.md
@@ -229,6 +229,7 @@ opencodex поставляется с 79 встроенными пресетам
 | SiliconFlow | `https://api.siliconflow.cn/v1` |
 | Volcengine Ark · Coding Plan · Agent Plan | `https://ark.cn-beijing.volces.com/api/v3` · `https://ark.cn-beijing.volces.com/api/coding/v3` · `https://ark.cn-beijing.volces.com/api/plan/v3` |
 | Xiaomi MiMo | `https://api.xiaomimimo.com/anthropic` |
+| Xiaomi MiMo (OpenAI Chat) | `https://api.xiaomimimo.com/v1` |
 | Kilo | `https://api.kilo.ai/api/gateway` |
 | GitLab Duo | `https://cloud.gitlab.com/ai/v1/proxy/openai/v1` |
 | Cloudflare AI Gateway | `https://gateway.ai.cloudflare.com/v1/{account-id}/{gateway}/anthropic` |
diff --git a/docs-site/src/content/docs/zh-cn/guides/providers.md b/docs-site/src/content/docs/zh-cn/guides/providers.md
index 1740e66e1..9537da4b4 100644
--- a/docs-site/src/content/docs/zh-cn/guides/providers.md
+++ b/docs-site/src/content/docs/zh-cn/guides/providers.md
@@ -206,6 +206,7 @@ Cline IDE/CLI 中提供，不能通过 API 使用；`minimax/minimax-m2.5` 是
 | SiliconFlow | `https://api.siliconflow.cn/v1` |
 | 火山方舟 · Coding Plan · Agent Plan | `https://ark.cn-beijing.volces.com/api/v3` · `https://ark.cn-beijing.volces.com/api/coding/v3` · `https://ark.cn-beijing.volces.com/api/plan/v3` |
 | Xiaomi MiMo | `https://api.xiaomimimo.com/anthropic` |
+| Xiaomi MiMo (OpenAI Chat) | `https://api.xiaomimimo.com/v1` |
 | Kilo | `https://api.kilo.ai/api/gateway` |
 | GitLab Duo | `https://cloud.gitlab.com/ai/v1/proxy/openai/v1` |
 | Cloudflare AI Gateway | `https://gateway.ai.cloudflare.com/v1/{account-id}/{gateway}/anthropic` |
diff --git a/docs-site/src/content/docs/zh-tw/guides/providers.md b/docs-site/src/content/docs/zh-tw/guides/providers.md
index b21bc6e98..cbbe1d38f 100644
--- a/docs-site/src/content/docs/zh-tw/guides/providers.md
+++ b/docs-site/src/content/docs/zh-tw/guides/providers.md
@@ -272,6 +272,7 @@ IDE／CLI，不透過 API；`minimax/minimax-m2.5` 是文件列出的 API 免費
 | SiliconFlow | `https://api.siliconflow.cn/v1` |
 | Volcengine Ark · Coding Plan · Agent Plan | `https://ark.cn-beijing.volces.com/api/v3` · `https://ark.cn-beijing.volces.com/api/coding/v3` · `https://ark.cn-beijing.volces.com/api/plan/v3` |
 | Xiaomi MiMo | `https://api.xiaomimimo.com/anthropic` |
+| Xiaomi MiMo (OpenAI Chat) | `https://api.xiaomimimo.com/v1` |
 | Kilo | `https://api.kilo.ai/api/gateway` |
 | GitLab Duo | `https://cloud.gitlab.com/ai/v1/proxy/openai/v1` |
 | Cloudflare AI Gateway | `https://gateway.ai.cloudflare.com/v1/{account-id}/{gateway}/anthropic` |
@@ -507,4 +508,4 @@ refresh 的即時 utilization bar。bar 代表特定 window（5 小時、weekly
 
 具有 live probe 的 provider：OpenAI/Codex、Anthropic、xAI、Cursor、Kimi、Google Antigravity、
 OpenRouter、DeepSeek、ClinePass、Z.AI、MiniMax、Moonshot、Venice、Synthetic、DeepInfra、Neuralwatt，
-以及任何由 a6api 支援的 custom provider。
\ No newline at end of file
+以及任何由 a6api 支援的 custom provider。
diff --git a/src/providers/registry.ts b/src/providers/registry.ts
index 54c623027..5f2f5c2ae 100644
--- a/src/providers/registry.ts
+++ b/src/providers/registry.ts
@@ -2303,6 +2303,24 @@ export const PROVIDER_REGISTRY: readonly ProviderRegistryEntry[] = [
     noVisionModels: OPENCODE_ZEN_TEXT_ONLY_MODELS,
   },
   { id: "xiaomi", label: "Xiaomi MiMo", baseUrl: "https://api.xiaomimimo.com/anthropic", adapter: "anthropic", authKind: "key", dashboardUrl: "https://xiaomimimo.com", defaultModel: "mimo-v2.5-pro" },
+  // Xiaomi's public OpenAI-compatible endpoint is a distinct transport from both the Anthropic
+  // preset above and the paid token-plan host below. Keep a separate fixed-destination contract
+  // so existing custom providers are never retargeted while the official route receives the
+  // strict reasoning ladder its validator enforces (#1483).
+  {
+    id: "xiaomi-mimo",
+    label: "Xiaomi MiMo (OpenAI Chat)",
+    baseUrl: "https://api.xiaomimimo.com/v1",
+    adapter: "openai-chat",
+    authKind: "key",
+    dashboardUrl: "https://platform.xiaomimimo.com/console/balance",
+    defaultModel: "mimo-v2.5",
+    models: ["mimo-v2.5"],
+    reasoningEfforts: ["low", "medium", "high"],
+    reasoningEffortMap: { xhigh: "high", max: "high", ultra: "high" },
+    preserveCustomDestination: true,
+    note: "Official Xiaomi MiMo OpenAI-compatible Chat endpoint. The upstream validator accepts reasoning_effort none/low/medium/high; higher Codex tiers are clamped to high.",
+  },
   { id: "kilo", label: "Kilo", baseUrl: "https://api.kilo.ai/api/gateway", adapter: "openai-chat", authKind: "key", dashboardUrl: "https://kilo.ai" },
   {
     id: "mimo-free",
diff --git a/structure/03_catalog-and-subagents.md b/structure/03_catalog-and-subagents.md
index d35f29272..5de606df0 100644
--- a/structure/03_catalog-and-subagents.md
+++ b/structure/03_catalog-and-subagents.md
@@ -150,6 +150,21 @@ wire-clamps ultra/max to each model's real top rung (e.g. gpt-5.5 ultra → xhig
 (`src/server/effort-policy.ts`): they lower or preserve the requested effort rather than rejecting
 the request, and they never raise it.
 
+[Decision Log]
+- 목적과 의도: Xiaomi MiMo의 공식 OpenAI Chat endpoint가 실제로 받지 않는 `max`/
+  `ultra` reasoning tier를 catalog에 노출하지 않도록 한다.
+- 기존 구현 및 제약 조건: `xiaomi`는 Anthropic endpoint, `mimo`는 token-plan endpoint를
+  소유하며, 공식 `https://api.xiaomimimo.com/v1`은 generic custom provider로 처리됐다.
+- 검토한 주요 대안: 기존 `xiaomi`/`mimo` contract를 확장하기, 모든 custom provider의 ladder를
+  일괄 축소하기, 공식 public endpoint만을 별도 registry row로 소유하기.
+- 선택한 방식: `xiaomi-mimo`를 고정 목적지의 `openai-chat` preset으로 등록하고
+  `low`/`medium`/`high`만 노출하며 높은 direct request는 `high`로 clamp한다.
+- 다른 대안 대신 이 방식을 선택한 이유: 서로 다른 auth/wire/host를 하나의 preset으로
+  합치지 않으면서 upstream error로 확인된 계약만 적용할 수 있다.
+- 장점, 단점 및 영향: 공식 endpoint에서 안전한 picker/wire 계약을 제공하고,
+  `preserveCustomDestination`으로 같은 이름의 다른 host/key를 보호한다. 대신 새 preset 표면을
+  문서와 registry parity에서 함께 유지해야 한다.
+
 [Decision Log]
 - 목적과 의도: bare `defaultModel` selectors that route into third-party providers must keep their
   adapter-owned effort ladder; only true ChatGPT-native requests should receive the mock-max repair.
diff --git a/tests/mimo-token-plan-provider.test.ts b/tests/mimo-token-plan-provider.test.ts
index 17314d6e7..83dfc0877 100644
--- a/tests/mimo-token-plan-provider.test.ts
+++ b/tests/mimo-token-plan-provider.test.ts
@@ -1,9 +1,74 @@
 import { describe, expect, test } from "bun:test";
+import { applyProviderConfigHints } from "../src/codex/catalog";
 import { KEY_LOGIN_PROVIDERS } from "../src/oauth/key-providers";
 import { PROVIDER_REGISTRY } from "../src/providers/registry";
+import { mapReasoningEffort } from "../src/reasoning-effort";
 import { routeModel } from "../src/router";
 import type { OcxConfig } from "../src/types";
 
+describe("Xiaomi MiMo public OpenAI Chat endpoint (#1483)", () => {
+  const baseUrl = "https://api.xiaomimimo.com/v1";
+  const entry = PROVIDER_REGISTRY.find(row => row.id === "xiaomi-mimo");
+
+  test("owns the official destination and advertises only its validated ladder", () => {
+    expect(entry).toMatchObject({
+      adapter: "openai-chat",
+      baseUrl,
+      dashboardUrl: "https://platform.xiaomimimo.com/console/balance",
+      defaultModel: "mimo-v2.5",
+      models: ["mimo-v2.5"],
+      preserveCustomDestination: true,
+      reasoningEfforts: ["low", "medium", "high"],
+    });
+    expect(KEY_LOGIN_PROVIDERS["xiaomi-mimo"]?.baseUrl).toBe(baseUrl);
+
+    const config: OcxConfig = {
+      port: 10100,
+      defaultProvider: "xiaomi-mimo",
+      providers: {
+        "xiaomi-mimo": {
+          adapter: "openai-chat",
+          baseUrl,
+          authMode: "key",
+          apiKey: "test-key",
+          liveModels: true,
+        },
+      },
+    };
+    const route = routeModel(config, "xiaomi-mimo/mimo-v2.5");
+    const catalogModel = applyProviderConfigHints("xiaomi-mimo", route.provider, {
+      provider: "xiaomi-mimo",
+      id: route.modelId,
+    });
+
+    expect(catalogModel.reasoningEfforts).toEqual(["low", "medium", "high"]);
+    for (const tier of ["xhigh", "max", "ultra"]) {
+      expect(mapReasoningEffort(route.provider, route.modelId, tier)).toBe("high");
+    }
+  });
+
+  test("does not claim a same-named provider at another destination", () => {
+    const config: OcxConfig = {
+      port: 10100,
+      defaultProvider: "xiaomi-mimo",
+      providers: {
+        "xiaomi-mimo": {
+          adapter: "openai-chat",
+          baseUrl: "https://private.example/v1",
+          authMode: "key",
+          apiKey: "private-key",
+        },
+      },
+    };
+
+    const route = routeModel(config, "xiaomi-mimo/mimo-v2.5");
+    expect(route.provider.baseUrl).toBe("https://private.example/v1");
+    expect(route.provider.apiKey).toBe("private-key");
+    expect(route.provider.reasoningEfforts).toBeUndefined();
+    expect(route.provider.reasoningEffortMap).toBeUndefined();
+  });
+});
+
 describe("Xiaomi MiMo token plan (#1158)", () => {
   const entry = PROVIDER_REGISTRY.find(row => row.id === "mimo");
 
diff --git a/tests/provider-registry-parity.test.ts b/tests/provider-registry-parity.test.ts
index f5ab05f11..1c08074ae 100644
--- a/tests/provider-registry-parity.test.ts
+++ b/tests/provider-registry-parity.test.ts
@@ -35,7 +35,7 @@ const EXPECTED_KEY_PROVIDER_IDS = [
   "huggingface", "nvidia", "venice", "zai", "zhipu-bigmodel", "zhipu-bigmodel-coding", "nanogpt", "synthetic", "siliconflow", "qwen-cloud", "tencent-coding-plan",
   "volcengine", "volcengine-coding-plan", "volcengine-agent-plan", "qianfan", "alibaba", "alibaba-token-plan", "alibaba-token-plan-intl", "parallel", "zenmux", "litellm", "ollama-cloud", "mistral",
   "minimax", "minimax-cn", "kimi-code", "opencode-zen", "vercel-ai-gateway",
-  "opencode-free", "xiaomi", "kilo", "mimo-free", "mimo", "cloudflare-ai-gateway", "cloudflare-workers-ai", "gitlab-duo",
+  "opencode-free", "xiaomi", "xiaomi-mimo", "kilo", "mimo-free", "mimo", "cloudflare-ai-gateway", "cloudflare-workers-ai", "gitlab-duo",
 ];
 
 describe("provider registry parity", () => {