import {z, type ZodRawShape, type ZodTypeAny} from 'zod';
type AliasMap = Record<string, string>;
/**
* Creates a strict Zod object schema that:
* 1. Accepts aliased parameter names (e.g., new_string -> new_str)
* 2. Rejects any unknown parameters after alias resolution
*/
export function strictSchemaWithAliases<T extends ZodRawShape>(
shape: T,
aliases: AliasMap = {},
): ZodTypeAny {
const objectSchema = z.object(shape).strict();
const effectsSchema = z.preprocess((args: unknown) => {
if (typeof args !== 'object' || args === null) {
return args;
}
const input = args as Record<string, unknown>;
const result: Record<string, unknown> = {};
// Build result object, mapping aliases to canonical names
for (const key of Object.keys(input)) {
const canonicalKey = aliases[key] ?? key;
// Only use alias if canonical key isn't already set
if (!(canonicalKey in result)) {
result[canonicalKey] = input[key];
}
}
return result;
}, objectSchema);
// Expose .shape so MCP SDK's normalizeObjectSchema can find the inner schema.
// Without this, the SDK falls back to an empty JSON schema for ZodEffects.
(effectsSchema as unknown as {shape: T}).shape = objectSchema.shape;
return effectsSchema;
}
