dotprompt 2.0.0

Dotprompt for Dart: parse and render .prompt files (YAML frontmatter + Handlebars templates) for Generative AI.

Changelog

All notable changes to dotprompt-dart will be documented in this file.

[Unreleased]

2.0.0 - 2026-10-04

Picoschema now follows the spec and behaves like the other runtimes. Schemas that relied on the old Dart-only syntax, or on unknown names becoming $ref, need updating.

Breaking changes

• Picoschema is strict. These now throw PicoschemaException:

  Before (1.x)	Now
  email(the email): string	email: string, the email
  tags: string[]	tags(array): string
  status: a | b	status(enum): [a, b]
  wild(*): string	(*): string
  n: int (also str, bool, ...)	n: integer
  a and a? in the same object	pick one

• Unknown named schemas throw instead of becoming {"$ref": name}. Names are looked up in schemas/defineSchema, then DotpromptOptions.schemaResolver (Dotprompt and Picoschema.parse only; toJsonSchema is sync and only sees schemas). Register schemas before converting prompts that use them.

• The input: Name / output: Name shorthand is parsed as {"$type": Name} (same as schema: Name) instead of {"$ref": Name}, so renderMetadata resolves it.

• Picoschema.toJsonSchema's schemas parameter is now Map<String, Map<String, dynamic>>? (was Map<String, dynamic>?).

• Picoschema.isPicoschema returns true for anything that is not JSON Schema (it used to require a bare scalar value). JSON Schema is detected as in the other runtimes: a top-level type naming a JSON Schema type or a properties map, plus list-valued type/anyOf/oneOf/allOf/enum, $schema and $ref. Calling it before toJsonSchema is no longer needed.

• DotpromptOptions.schemas and defineSchema take JSON Schema (as in the other runtimes), not Picoschema. Registered schemas are inserted as-is; convert Picoschema with Picoschema.toJsonSchema first.

Fixed

• Picoschema now follows the spec and the JavaScript reference implementation (genkit-dart#562):
  • field(array[, desc]): type, field(object[, desc]): and field(enum[, desc]): [...] produce arrays, objects and enums. Previously the parenthesized qualifier was treated as a description.
  • (*) wildcards and every Picoschema form are always converted. Previously some schemas skipped conversion and were passed through raw.
  • Top-level JSON Schema (type: string, a bare properties map, anyOf, enum, type: [string, "null"], etc.) is passed through instead of being parsed as Picoschema.
  • Passed-through JSON Schema and resolved named schemas are deep copies, so editing the result never changes the input or registered schemas.
  • A frontmatter schema with a $type field next to other fields is parsed as a Picoschema object instead of being collapsed to the $type value.
  • x?: null produces {type: null} instead of {type: [null, null]}.
  • a ?: string produces a property named a, not a .
  • Named schemas are resolved via DotpromptOptions.schemaResolver as well as schemas/defineSchema.
  • The input: Name / output: Name shorthand resolves the named schema. Previously it became a raw {"$ref": name}.
• The spec test runner now checks output and named schemas, so spec/picoschema.yaml is actually enforced.

Added

• Picoschema.parse(schema, {schemas, schemaResolver}), an async variant of toJsonSchema that resolves named schemas through a SchemaResolver.

1.0.0 - 2026-08-25

Added

• renderMetadata and compile now accept an optional additionalMetadata argument that is merged on top of the prompt's parsed frontmatter (scalar fields override, config map is shallow-merged with additional winning on conflict), matching the JavaScript reference implementation.

0.0.1 - 2026-01-30

Added

• Initial release of Dotprompt for Dart
• YAML frontmatter parsing with Parser class
• Handlebars-style templating using the pure-Dart handlebars_dart library
• Picoschema to JSON Schema conversion
• Core types: Message, Part, Role, DataArgument
• Built-in helpers: role, media, history, json, section, ifEquals, unlessEquals
• Partial template support with resolver callbacks
• Tool and schema resolution
• Comprehensive error handling with custom exceptions
• Full spec test suite for cross-runtime conformance