diff --git a/.changeset/add-zai-glm-provider.md b/.changeset/add-zai-glm-provider.md
new file mode 100644
index 00000000..6075d505
--- /dev/null
+++ b/.changeset/add-zai-glm-provider.md
@@ -0,0 +1,6 @@
+---
+"@open-codesign/shared": minor
+"@open-codesign/providers": patch
+---
+
+Add Z.ai (GLM Coding Plan) as a built-in provider with support for GLM-5.1, GLM-5-Turbo, GLM-4.7, and GLM-4.5-Air models via the Anthropic-compatible API endpoint.
diff --git a/packages/providers/src/validate.ts b/packages/providers/src/validate.ts
index 0336b283..89ca98f9 100644
--- a/packages/providers/src/validate.ts
+++ b/packages/providers/src/validate.ts
@@ -67,6 +67,19 @@ function endpoint(provider: SupportedOnboardingProvider, baseUrl?: string): Prov
         headers: () => ({}),
       };
     }
+    case 'zai': {
+      const root = baseUrl ? normalizeValidateBaseUrl(baseUrl) : 'https://api.z.ai/api/anthropic';
+      return {
+        url: `${root}/v1/models`,
+        headers: (apiKey) => {
+          const auth: Record<string, string> = {
+            'x-api-key': apiKey,
+            'anthropic-version': '2023-06-01',
+          };
+          return withClaudeCodeIdentity('anthropic', baseUrl, auth);
+        },
+      };
+    }
   }
 }
 
diff --git a/packages/shared/src/config.test.ts b/packages/shared/src/config.test.ts
index 129396be..8852be94 100644
--- a/packages/shared/src/config.test.ts
+++ b/packages/shared/src/config.test.ts
@@ -499,3 +499,46 @@ describe('provider capability helpers', () => {
     expect(caps.modelDiscoveryMode).toBe('manual');
   });
 });
+
+describe('zai builtin provider', () => {
+  it('has a well-formed zai entry in BUILTIN_PROVIDERS', () => {
+    const zai = BUILTIN_PROVIDERS.zai;
+    expect(zai).toBeDefined();
+    expect(zai.id).toBe('zai');
+    expect(zai.name).toBe('Z.ai (GLM Coding Plan)');
+    expect(zai.builtin).toBe(true);
+    expect(zai.wire).toBe('anthropic');
+    expect(zai.baseUrl).toBe('https://api.z.ai/api/anthropic');
+    expect(zai.defaultModel).toBe('glm-5.1');
+    expect(zai.modelsHint).toEqual(['glm-5.1', 'glm-5-turbo', 'glm-4.7', 'glm-4.5-air']);
+    expect(zai.requiresApiKey).toBe(true);
+  });
+
+  it('zai capabilities are set for static-hint discovery with reasoning', () => {
+    const caps = resolveProviderCapabilities('zai', BUILTIN_PROVIDERS.zai);
+    expect(caps.supportsKeyless).toBe(false);
+    expect(caps.supportsModelsEndpoint).toBe(false);
+    expect(caps.supportsReasoning).toBe(true);
+    expect(caps.modelDiscoveryMode).toBe('static-hint');
+  });
+
+  it('zai is included in SUPPORTED_ONBOARDING_PROVIDERS', () => {
+    expect(SUPPORTED_ONBOARDING_PROVIDERS).toContain('zai');
+  });
+
+  it('detects z.ai anthropic URL as anthropic wire', () => {
+    expect(detectWireFromBaseUrl('https://api.z.ai/api/anthropic')).toBe('anthropic');
+  });
+
+  it('accepts zai as active provider in v3 config', () => {
+    const parsed = ConfigV3Schema.parse({
+      version: 3,
+      activeProvider: 'zai',
+      activeModel: 'glm-5.1',
+      secrets: { zai: { ciphertext: 'plain:sk-test', mask: 'sk-***test' } },
+      providers: { zai: BUILTIN_PROVIDERS.zai },
+    });
+    expect(parsed.activeProvider).toBe('zai');
+    expect(parsed.activeModel).toBe('glm-5.1');
+  });
+});
diff --git a/packages/shared/src/config.ts b/packages/shared/src/config.ts
index 12aac774..4e34b3bb 100644
--- a/packages/shared/src/config.ts
+++ b/packages/shared/src/config.ts
@@ -21,6 +21,7 @@ export const SUPPORTED_ONBOARDING_PROVIDERS = [
   'openai',
   'openrouter',
   'ollama',
+  'zai',
 ] as const;
 export type SupportedOnboardingProvider = (typeof SUPPORTED_ONBOARDING_PROVIDERS)[number];
 
@@ -294,6 +295,23 @@ export const BUILTIN_PROVIDERS: Readonly<Record<SupportedOnboardingProvider, Pro
       modelDiscoveryMode: 'models',
     },
   },
+  zai: {
+    id: 'zai',
+    name: 'Z.ai (GLM Coding Plan)',
+    builtin: true,
+    wire: 'anthropic',
+    baseUrl: 'https://api.z.ai/api/anthropic',
+    defaultModel: 'glm-5.1',
+    modelsHint: ['glm-5.1', 'glm-5-turbo', 'glm-4.7', 'glm-4.5-air'],
+    requiresApiKey: true,
+    capabilities: {
+      supportsKeyless: false,
+      supportsModelsEndpoint: false,
+      supportsReasoning: true,
+      requiresClaudeCodeIdentity: false,
+      modelDiscoveryMode: 'static-hint',
+    },
+  },
 } as const;
 
 // ── ConfigSchema v3 — canonical on-disk shape ────────────────────────────────
@@ -514,6 +532,13 @@ export const PROVIDER_SHORTLIST: Record<SupportedOnboardingProvider, ProviderSho
     primary: [OLLAMA_DEFAULT_MODEL, 'llama3.1', 'qwen2.5'],
     defaultPrimary: OLLAMA_DEFAULT_MODEL,
   },
+  zai: {
+    provider: 'zai',
+    label: 'Z.ai (GLM Coding Plan)',
+    keyHelpUrl: 'https://z.ai/manage-apikey/apikey-list',
+    primary: ['glm-5.1', 'glm-5-turbo', 'glm-4.7', 'glm-4.5-air'],
+    defaultPrimary: 'glm-5.1',
+  },
 };
 
 export function isSupportedOnboardingProvider(p: string): p is SupportedOnboardingProvider {
diff --git a/packages/shared/src/proxy-presets.ts b/packages/shared/src/proxy-presets.ts
index fd1a2fb7..145e25b4 100644
--- a/packages/shared/src/proxy-presets.ts
+++ b/packages/shared/src/proxy-presets.ts
@@ -59,6 +59,13 @@ export const PROXY_PRESETS = [
     baseUrl: 'http://127.0.0.1:8317',
     notes: '',
   },
+  {
+    id: 'zai-glm',
+    label: 'Z.ai GLM Coding Plan',
+    provider: 'anthropic',
+    baseUrl: 'https://api.z.ai/api/anthropic',
+    notes: 'GLM-5.1, GLM-5-Turbo, GLM-4.7, GLM-4.5-Air',
+  },
   {
     id: 'custom',
     label: 'Custom...',