llm_schema library

Zod-style schema validation for LLM structured outputs.

Define a schema once and use it to:

• validate JSON produced by a language model into typed Dart values, with precise, path-aware error messages you can feed back to the model for a retry;
• emit JSON Schema (toJsonSchema) for tool-parameter definitions and structured-output APIs;
• parse raw model text (parseText) that wraps JSON in Markdown code fences, prose, or trailing commas.

Classes

AnyOfSchema<T>

Matches if any of options matches; the first success wins.

AnySchema

Matches any JSON value unchanged.

BoolSchema

Matches JSON booleans.

DefaultSchema<T>

Supplies a default when input is null or absent. See Schema.withDefault.

DescribedSchema<T>

Attaches a JSON Schema description. See Schema.describe.

DoubleSchema

Matches JSON numbers (integers or doubles), producing a double.

EnumOfSchema<T extends Enum>

Matches the names of a Dart enum, producing the enum value itself.

EnumSchema

Matches one of a fixed set of strings.

IntSchema

Matches JSON integers. Whole-valued doubles such as 5.0 — which some models emit for integer fields — are accepted and truncated to int.

ListSchema<T>

Matches JSON arrays whose every element matches items.

LiteralSchema<T>

Matches exactly one value, compared with ==.

MapSchema<V>

Matches JSON objects used as dictionaries: arbitrary string keys, all values matching values.

NullableSchema<T>

Accepts null in addition to the inner schema's values.

ObjectSchema

Matches JSON objects with a fixed set of named fields.

OptionalSchema<T>

Marks an object field as omittable. See Schema.optional.

RefineSchema<T>

Adds a custom predicate check. See Schema.refine.

S

Entry point for building schemas, in the spirit of TypeScript's z.

Schema<T>

Base class for all schemas.

SchemaFailure<T>

A failed validation carrying every SchemaIssue that was found.

SchemaIssue

A single validation problem found while checking input against a schema.

SchemaResult<T>

The outcome of validating a value against a Schema<T>.

SchemaSuccess<T>

A successful validation carrying the parsed value.

StringSchema

Matches JSON strings, with optional length/pattern constraints.

TransformSchema<I, O>

Maps a validated value to another type. See Schema.transform.

Functions

extractJson(String text) → Object?

Extracts and decodes the first JSON value found in text.

Exceptions / Errors

SchemaValidationException

Thrown by Schema.parse and Schema.parseText when validation fails.