Zod to JSON Schema conversion

zodToJsonSchema(schema, options) converts common Zod types into JSON Schema used for prompt injection and provider-native structured output.

const generic = zodToJsonSchema(schema)
const strict = zodToJsonSchema(schema, { strict: true })

Generic mode

Generic mode is optimized for prompt injection and JSON-mode providers.

• Optional/default/catch properties are not added to required.
• nullable(T) becomes T plus nullable: true.
• Objects set additionalProperties: false.

Strict mode

Strict mode is used for json_schema and tool_call requests.

• Every object key is listed in required.
• Optional/default/catch properties become anyOf [T, { type: 'null' }].
• Nullable properties become anyOf [T, null] instead of the non-standard nullable keyword.

Supported types

Zod	JSON Schema
string()	type: 'string' plus min/max/length/email/url/uuid/regex checks
number()	type: 'number'; .int() becomes integer; min/max/multipleOf mapped
boolean()	type: 'boolean'
literal(v)	enum: [v]
enum / nativeEnum	enum: [...]
array(T)	type: 'array', items, min/max/exact length
object({...})	properties, required, additionalProperties: false
record(V)	type: 'object', additionalProperties: V
union([...])	anyOf
discriminatedUnion	oneOf
tuple([...])	prefixItems, minItems, maxItems; optional rest mapped to items
intersection(A, B)	allOf
date()	type: 'string', format: 'date-time'
wrappers	optional/default/catch/readonly/branded/effects/pipeline are unwrapped with description preserved

Unsupported types fall back to a description marker instead of throwing, so prompt-based flows can still run while native strict flows should be tested before rollout.