visual_brief_lint #

Validate structured AI image briefs before they reach a generation or editing workflow. The package is dependency-free and works in Dart command-line, server, web, and Flutter projects.

Features #

• Model a portable visual brief with subject, composition, style, constraints, reference assets, negative prompts, and output requirements.
• Read and write JSON-compatible maps.
• Catch missing creative direction, invalid dimensions, unsupported formats, and duplicate reference IDs.
• Separate blocking errors from non-blocking warnings.
• Configure maximum dimensions and allowed output formats.

Getting started #

Add the package:

dart pub add visual_brief_lint

Usage #

import 'package:visual_brief_lint/visual_brief_lint.dart';

void main() {
  const brief = VisualBrief(
    subject: 'A reusable glass bottle with a white paper label',
    composition: 'Centered product shot at eye level with generous margin',
    style: 'Clean studio photography with soft directional light',
    constraints: ['Keep the label blank', 'No hands or people'],
    output: VisualOutputSpec(width: 1200, height: 1200),
    referenceAssetIds: ['bottle-front'],
  );

  const linter = VisualBriefLinter();
  final issues = linter.lint(brief);

  if (issues.isEmpty) {
    print('Brief is ready for generation.');
  } else {
    issues.forEach(print);
  }
}

The linter is intentionally model-agnostic. It can sit before an internal image API, a queue, or a third-party workflow. For example, a team drafting prompts and object-reference edits in Nano Banana 2 Lite can validate the brief structure before handing it to the generation stage.

JSON input #

final brief = VisualBrief.fromJson({
  'subject': 'A compact desk lamp with a brushed metal base',
  'composition': 'Side view on a clear desk with negative space',
  'style': 'Minimal product photograph with natural shadows',
  'constraints': ['Keep the power cable visible'],
  'output': {'width': 1400, 'height': 1000, 'format': 'webp'},
});

final issues = const VisualBriefLinter().lint(brief);

Use isValid when only a pass/fail result is needed. Use lint when a UI or pipeline should show actionable feedback.

Contributing #

Issues and focused pull requests are welcome in the GitHub repository. Please include tests for new rules and keep rules deterministic.