FlowiseAI/Flowise · error · Error

Failed to parse Zod schema: ${error.message}

Error message

Failed to parse Zod schema: ${error.message}

What it means

parseZodSchema is the single public entry of SecureZodSchemaParser. Its try-block runs cleanSchemaString -> parseSchemaStructure -> buildZodSchema; any error is caught and rethrown as 'Failed to parse Zod schema: <error.message>'. This nests the inner message (which is itself one of errors 608-619) and discards the original stack, hiding the precise throw site. To find the real cause, read the suffix after the colon.

Source

Thrown at packages/components/src/secureZodParser.ts:40

    /**
     * Safely parse a Zod schema string into a Zod schema object
     * @param schemaString The Zod schema as a string (e.g., "z.object({name: z.string()})")
     * @returns A Zod schema object
     * @throws Error if the schema is invalid or contains unsafe patterns
     */
    static parseZodSchema(schemaString: string): z.ZodTypeAny {
        try {
            // Remove comments and normalize whitespace
            const cleanedSchema = this.cleanSchemaString(schemaString)

            // Parse the schema structure
            const parsed = this.parseSchemaStructure(cleanedSchema)

            // Build the Zod schema securely
            return this.buildZodSchema(parsed)
        } catch (error) {
            throw new Error(`Failed to parse Zod schema: ${error.message}`)
        }
    }

    private static cleanSchemaString(schema: string): string {
        // Remove single-line comments
        schema = schema.replace(/\/\/.*$/gm, '')

        // Remove multi-line comments
        schema = schema.replace(/\/\*[\s\S]*?\*\//g, '')

        // Normalize whitespace
        schema = schema.replace(/\s+/g, ' ').trim()

        return schema
    }

    private static parseSchemaStructure(schema: string): any {
        // This is a simplified parser that handles common Zod patterns safely

View on GitHub (pinned to abe4a8601a)

Solutions

1. Read the suffix after 'Failed to parse Zod schema: ' to identify the underlying error (608-619) and fix that.
2. Simplify the schema to the supported subset: top-level z.object, base types in ALLOWED_TYPES, modifiers in ALLOWED_TYPES.
3. As a maintainer: preserve the original error via 'throw new Error(msg, { cause: error })' so the stack survives.

Example fix

// before: caller loses the underlying cause
try { SecureZodSchemaParser.parseZodSchema(str) } catch (e) { console.log(e.message) }
// -> 'Failed to parse Zod schema: Unsupported type: bigint'  (read the suffix)

// fix the schema: replace unsupported type
// before: 'z.object({ id: z.bigint() })'
// after:  'z.object({ id: z.string() })'

// Validate shape before parsing using the same rules the parser enforces.
function looksParsable(s: string): boolean {
  const c = s.replace(/\/\/.*$/gm, '').replace(/\/\*[\s\S]*?\*\//g, '').replace(/\s+/g, ' ').trim()
  return c.startsWith('z.object(') && /z\.object\(\s*\{[\s\S]*\}\s*\)/.test(c)
}

const isZodSchemaString = (s: unknown): s is string =>
  typeof s === 'string' && s.replace(/\s+/g, ' ').trim().startsWith('z.object(')

try {
  return SecureZodSchemaParser.parseZodSchema(schemaString)
} catch (e) {
  // the suffix after 'Failed to parse Zod schema: ' is the real cause
  const cause = (e as Error).message.replace(/^Failed to parse Zod schema: /, '')
  throw new Error(`Schema rejected (${cause})`, { cause: e })
}

When it happens

Trigger: Any malformed or unsupported schema string passed to SecureZodSchemaParser.parseZodSchema — the specific reason is the suffix (e.g. '... Schema must start with z.object()', '... Unsupported type: bigint').

Common situations: User-defined tool/input schema stored as a string and parsed at runtime; schema written against full Zod but the secure parser only supports a subset; copy-pasting a Zod schema from docs that uses unsupported types/modifiers.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• Schema must start with z.object()
• Invalid z.object() syntax
• Invalid object syntax
• Expected 'z' but got '${part}'
• Invalid base type: ${part}

AI-assisted analysis of FlowiseAI/Flowise@abe4a8601a (2026-08-12). Data as JSON: /api/errors/d0ca7e66665fd696. Report an issue: GitHub.