What problem does it solve? Keeping a hand-written Dart SDK in sync with the evolving Anthropic OpenAPI specification is error-prone: new content blocks, built-in tools, and beta-gated resources are easy to miss or wire incorrectly. This Skill provides a repeatable fetch-review-scaffold-verify workflow so spec changes are detected, implemented, and validated systematically. ## Core Features & Use Cases - Spec Fetch & Review: Downloads the latest Anthropic OpenAPI spec, compares it against the pinned hash, and reports what changed via the shared api-toolkit CLI. - Scaffolding & Implementation Guidance: Generates model scaffolds and provides package-specific patterns for built-in tool routing, input/output content block pairing, and enum round-trip fidelity. - Verification & Documentation: Runs coverage and export checks, then guides updates to examples, README, and llms.txt before opening a PR. - Use Case: When Anthropic ships a new built-in tool in the API spec, run the fetch and review commands, scaffold the new schema, wire it into BuiltInTool and ToolDefinition, then verify and update docs. ## Quick Start Ask the AI to fetch the latest Anthropic OpenAPI spec and review what changed for the anthropic_sdk_dart package.