fix: handle anyOf/oneOf/ in JSON schema to Zod conversion (CopilotKit#2220)

Author: jpr5

packages/shared/src/utils/json-schema.ts

@@ -241,7 +241,36 @@ function convertAttribute(attribute: Parameter): JSONSchema {
 export function convertJsonSchemaToZodSchema(
   jsonSchema: any,
   required: boolean,
+  definitions?: Record<string, any>,
 ): z.ZodSchema {
+  // Resolve $ref references
+  if (jsonSchema.$ref && definitions) {
+    const refPath = jsonSchema.$ref.replace(/^#\/\$defs\/|^#\/definitions\//, "");
+    const resolved = definitions[refPath];
+    if (resolved) {
+      return convertJsonSchemaToZodSchema(resolved, required, definitions);
+    }
+  }
+
+  // Collect top-level definitions for $ref resolution
+  const defs = definitions ?? jsonSchema.$defs ?? jsonSchema.definitions;
+
+  // Handle anyOf / oneOf as z.union
+  const unionVariants = jsonSchema.anyOf ?? jsonSchema.oneOf;
+  if (Array.isArray(unionVariants) && unionVariants.length > 0) {
+    if (unionVariants.length === 1) {
+      return convertJsonSchemaToZodSchema(unionVariants[0], required, defs);
+    }
+    const schemas = unionVariants.map((v: any) =>
+      convertJsonSchemaToZodSchema(v, true, defs),
+    );
+    let schema = z.union(schemas as [z.ZodSchema, z.ZodSchema, ...z.ZodSchema[]]);
+    if (jsonSchema.description) {
+      schema = schema.describe(jsonSchema.description);
+    }
+    return required ? schema : schema.optional();
+  }
+
   if (jsonSchema.type === "object") {
     const spec: { [key: string]: z.ZodSchema } = {};
 
@@ -253,6 +282,7 @@ export function convertJsonSchemaToZodSchema(
       spec[key] = convertJsonSchemaToZodSchema(
         value,
         jsonSchema.required ? jsonSchema.required.includes(key) : false,
+        defs,
       );
     }
     let schema = z.object(spec).describe(jsonSchema.description);
@@ -266,18 +296,27 @@ export function convertJsonSchemaToZodSchema(
     }
     let schema = z.string().describe(jsonSchema.description);
     return required ? schema : schema.optional();
-  } else if (jsonSchema.type === "number") {
+  } else if (jsonSchema.type === "number" || jsonSchema.type === "integer") {
     let schema = z.number().describe(jsonSchema.description);
     return required ? schema : schema.optional();
   } else if (jsonSchema.type === "boolean") {
     let schema = z.boolean().describe(jsonSchema.description);
     return required ? schema : schema.optional();
   } else if (jsonSchema.type === "array") {
-    let itemSchema = convertJsonSchemaToZodSchema(jsonSchema.items, true);
+    let itemSchema = convertJsonSchemaToZodSchema(jsonSchema.items, true, defs);
     let schema = z.array(itemSchema).describe(jsonSchema.description);
     return required ? schema : schema.optional();
+  } else if (jsonSchema.type === "null") {
+    let schema = z.null().describe(jsonSchema.description);
+    return required ? schema : schema.optional();
+  }
+
+  // Fallback: accept any value rather than throwing
+  let schema = z.any();
+  if (jsonSchema.description) {
+    schema = schema.describe(jsonSchema.description);
   }
-  throw new Error("Invalid JSON schema");
+  return required ? schema : schema.optional();
 }
 
 export function getZodParameters<T extends [] | Parameter[] | undefined>(