feat(zai): auto-detect endpoint + default glm-5 (#14786)

* feat(zai): auto-detect endpoint + default glm-5

* test: fix Z.AI default endpoint expectation (#14786)

* test: bump embedded runner beforeAll timeout

* chore: update changelog for Z.AI GLM-5 autodetect (#14786)

* chore: resolve changelog merge conflict with main (#14786)

* chore: append changelog note for #14786 without merge conflict

* chore: sync changelog with main to resolve merge conflict

src/agents/pi-embedded-runner/model.ts

@@ -114,6 +114,51 @@ function resolveAnthropicOpus46ForwardCompatModel(
   return undefined;
 }
 
+// Z.ai's GLM-5 may not be present in pi-ai's built-in model catalog yet.
+// When a user configures zai/glm-5 without a models.json entry, clone glm-4.7 as a forward-compat fallback.
+const ZAI_GLM5_MODEL_ID = "glm-5";
+const ZAI_GLM5_TEMPLATE_MODEL_IDS = ["glm-4.7"] as const;
+
+function resolveZaiGlm5ForwardCompatModel(
+  provider: string,
+  modelId: string,
+  modelRegistry: ModelRegistry,
+): Model<Api> | undefined {
+  if (normalizeProviderId(provider) !== "zai") {
+    return undefined;
+  }
+  const trimmed = modelId.trim();
+  const lower = trimmed.toLowerCase();
+  if (lower !== ZAI_GLM5_MODEL_ID && !lower.startsWith(`${ZAI_GLM5_MODEL_ID}-`)) {
+    return undefined;
+  }
+
+  for (const templateId of ZAI_GLM5_TEMPLATE_MODEL_IDS) {
+    const template = modelRegistry.find("zai", templateId) as Model<Api> | null;
+    if (!template) {
+      continue;
+    }
+    return normalizeModelCompat({
+      ...template,
+      id: trimmed,
+      name: trimmed,
+      reasoning: true,
+    } as Model<Api>);
+  }
+
+  return normalizeModelCompat({
+    id: trimmed,
+    name: trimmed,
+    api: "openai-completions",
+    provider: "zai",
+    reasoning: true,
+    input: ["text"],
+    cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+    contextWindow: DEFAULT_CONTEXT_TOKENS,
+    maxTokens: DEFAULT_CONTEXT_TOKENS,
+  } as Model<Api>);
+}
+
 // google-antigravity's model catalog in pi-ai can lag behind the actual platform.
 // When a google-antigravity model ID contains "opus-4-6" (or "opus-4.6") but isn't
 // in the registry yet, clone the opus-4-5 template so the correct api
@@ -242,6 +287,10 @@ export function resolveModel(
     if (antigravityForwardCompat) {
       return { model: antigravityForwardCompat, authStorage, modelRegistry };
     }
+    const zaiForwardCompat = resolveZaiGlm5ForwardCompatModel(provider, modelId, modelRegistry);
+    if (zaiForwardCompat) {
+      return { model: zaiForwardCompat, authStorage, modelRegistry };
+    }
     const providerCfg = providers[provider];
     if (providerCfg || modelId.startsWith("mock-")) {
       const fallbackModel: Model<Api> = normalizeModelCompat({