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feat: Add duck-typed isZodType guard for Zod schemas across bundles #473

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feat: Add duck-typed isZodType guard for Zod schemas across bundles #473

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e0c35b6
Use runtime guard for Zod types that works across bundles
bohdan-romanchenko May 9, 2025
f6262a0
Merge branch 'main' of github.com:bohdan-romanchenko/typescript-sdk
bohdan-romanchenko May 9, 2025
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18 changes: 17 additions & 1 deletion src/server/mcp.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -660,14 +660,30 @@ export class McpServer {
throw new Error(`Tool ${name} is already registered`);
}

// Runtime type guard for Zod types that works across bundles/realms
const isZodType = (value: unknown): value is ZodTypeAny => {
if (typeof value !== "object" || value === null) return false;

if (!("_def" in value)) return false;

const def = (value as { _def: unknown })._def;
if (typeof def !== "object" || def === null) return false;

if (!("typeName" in def)) return false;

return typeof (def as { typeName: unknown }).typeName === "string";
};

// Helper to check if an object is a Zod schema (ZodRawShape)
const isZodRawShape = (obj: unknown): obj is ZodRawShape => {
if (typeof obj !== "object" || obj === null) return false;

const isEmptyObject = z.object({}).strict().safeParse(obj).success;

// Check if object is empty or at least one property is a ZodType instance
return isEmptyObject || Object.values(obj as object).some(v => v instanceof ZodType);
return (
isEmptyObject || Object.values(obj as object).some((v) => isZodType(v))
);
};

let description: string | undefined;
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