diff --git a/packages/opencode/src/provider/transform.ts b/packages/opencode/src/provider/transform.ts
index f78cc53e75..e459380faa 100644
--- a/packages/opencode/src/provider/transform.ts
+++ b/packages/opencode/src/provider/transform.ts
@@ -666,6 +666,9 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
   if (!model.capabilities.reasoning) return {}
 
   const id = model.id.toLowerCase()
+  const glm52 = ["glm-5.2", "glm-5-2", "glm-5p2"].some(
+    (name) => id.includes(name) || model.api.id.toLowerCase().includes(name),
+  )
   if (
     model.api.id.toLowerCase().includes("minimax-m3") &&
     ["@ai-sdk/anthropic", "@ai-sdk/openai-compatible"].includes(model.api.npm)
@@ -677,13 +680,32 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
   }
   const adaptiveThinkingOmitted = anthropicOmitsThinking(model.api.id)
   const adaptiveEfforts = anthropicAdaptiveEfforts(model.api.id)
+  if (glm52 && model.api.npm === "@openrouter/ai-sdk-provider") {
+    // OpenRouter maps xhigh to GLM-5.2's native max effort.
+    return {
+      high: { reasoning: { effort: "high" } },
+      xhigh: { reasoning: { effort: "xhigh" } },
+    }
+  }
+  if (glm52 && model.api.npm === "@ai-sdk/openai-compatible") {
+    return {
+      high: { reasoningEffort: "high" },
+      max: { reasoningEffort: "max" },
+    }
+  }
+  if (glm52 && model.api.npm === "@ai-sdk/anthropic") {
+    return {
+      high: { effort: "high" },
+      max: { effort: "max" },
+    }
+  }
   if (
     id.includes("deepseek-chat") ||
     id.includes("deepseek-reasoner") ||
     id.includes("deepseek-r1") ||
     id.includes("deepseek-v3") ||
     id.includes("minimax") ||
-    id.includes("glm") ||
+    (id.includes("glm") && !glm52) ||
     id.includes("kimi") ||
     id.includes("k2p") ||
     id.includes("qwen") ||
diff --git a/packages/opencode/test/provider/transform.test.ts b/packages/opencode/test/provider/transform.test.ts
index 04d75bfba2..5fa530155d 100644
--- a/packages/opencode/test/provider/transform.test.ts
+++ b/packages/opencode/test/provider/transform.test.ts
@@ -2895,6 +2895,102 @@ describe("ProviderTransform.variants", () => {
     expect(result).toEqual({})
   })
 
+  test("glm-5.2 returns native effort variants for openai-compatible providers", () => {
+    const model = createMockModel({
+      id: "zhipuai/glm-5.2",
+      providerID: "zhipuai",
+      api: {
+        id: "glm-5.2",
+        url: "https://open.bigmodel.cn/api/paas/v4",
+        npm: "@ai-sdk/openai-compatible",
+      },
+    })
+    expect(ProviderTransform.variants(model)).toEqual({
+      high: { reasoningEffort: "high" },
+      max: { reasoningEffort: "max" },
+    })
+  })
+
+  test("recognizes GLM-5.2 provider model IDs", () => {
+    for (const id of ["accounts/fireworks/models/glm-5p2", "zai-org-glm-5-2", "umans-glm-5.2"]) {
+      const model = createMockModel({
+        id: `test/${id}`,
+        api: {
+          id,
+          url: "https://api.test.com",
+          npm: "@ai-sdk/openai-compatible",
+        },
+      })
+      expect(ProviderTransform.variants(model)).toEqual({
+        high: { reasoningEffort: "high" },
+        max: { reasoningEffort: "max" },
+      })
+    }
+  })
+
+  test("recognizes GLM-5.2 from the API ID when the configured model ID is an alias", () => {
+    const model = createMockModel({
+      id: "custom/my-glm",
+      api: {
+        id: "accounts/fireworks/models/glm-5p2",
+        url: "https://api.fireworks.ai/inference/v1",
+        npm: "@ai-sdk/openai-compatible",
+      },
+    })
+    expect(ProviderTransform.variants(model)).toEqual({
+      high: { reasoningEffort: "high" },
+      max: { reasoningEffort: "max" },
+    })
+  })
+
+  test("glm-5.2 returns openrouter effort variants for openrouter", () => {
+    const model = createMockModel({
+      id: "openrouter/z-ai/glm-5.2",
+      providerID: "openrouter",
+      api: {
+        id: "z-ai/glm-5.2",
+        url: "https://openrouter.ai/api/v1",
+        npm: "@openrouter/ai-sdk-provider",
+      },
+    })
+    expect(ProviderTransform.variants(model)).toEqual({
+      high: { reasoning: { effort: "high" } },
+      xhigh: { reasoning: { effort: "xhigh" } },
+    })
+  })
+
+  test("glm-5.2 returns effort variants for anthropic-compatible providers", () => {
+    const model = createMockModel({
+      id: "zai-coding-plan/glm-5.2",
+      providerID: "zai-coding-plan",
+      api: {
+        id: "glm-5.2",
+        url: "https://api.z.ai/api/anthropic",
+        npm: "@ai-sdk/anthropic",
+      },
+    })
+    expect(ProviderTransform.variants(model)).toEqual({
+      high: { effort: "high" },
+      max: { effort: "max" },
+    })
+  })
+
+  test("glm-5.2 falls back to provider defaults for other packages", () => {
+    const model = createMockModel({
+      id: "test/glm-5.2",
+      api: {
+        id: "glm-5.2",
+        url: "https://api.test.com",
+        npm: "@ai-sdk/amazon-bedrock",
+      },
+    })
+    expect(ProviderTransform.variants(model)).toEqual({
+      low: { reasoningConfig: { type: "enabled", maxReasoningEffort: "low" } },
+      medium: { reasoningConfig: { type: "enabled", maxReasoningEffort: "medium" } },
+      high: { reasoningConfig: { type: "enabled", maxReasoningEffort: "high" } },
+    })
+  })
+
   test("mistral models with reasoning support return variants", () => {
     const model = createMockModel({
       id: "mistral/mistral-small-latest",