# What AI Coding Assistants Does Hallmark Support? A Complete Guide > Discover which AI coding assistants Hallmark supports including ChatGPT, Claude, and Gemini. Learn how Hallmark's skill-based architecture enables broad AI integration. - Repository: [Hassan El Mghari/hallmark](https://github.com/Nutlope/hallmark) - Tags: getting-started - Published: 2026-07-16 --- **Hallmark supports any AI coding assistant capable of invoking skills, including ChatGPT, Claude, Gemini, and Together AI, through its generic skill-based architecture defined in [`skills/hallmark/SKILL.md`](https://github.com/Nutlope/hallmark/blob/main/skills/hallmark/SKILL.md).** The Nutlope/hallmark repository implements a design system that works across different AI coding assistants. Rather than locking into a single vendor, Hallmark exposes itself as a universal skill that any LLM-based coding assistant can invoke to generate polished, professional user interfaces. ## How Hallmark Integrates with AI Coding Assistants Hallmark operates as an **assistant-agnostic design skill**. According to the source code in [`skills/hallmark/SKILL.md`](https://github.com/Nutlope/hallmark/blob/main/skills/hallmark/SKILL.md), the project is explicitly described as "A design skill for **AI coding assistants**." This architecture means there is no hard-coded list of supported assistants in the codebase. The integration works through a generic skill-calling interface. When an AI coding assistant supports skill or tool invocation, it can send a JSON request to Hallmark's endpoint and receive design-system guidance in return. This approach ensures compatibility with both current and future AI coding assistants that implement skill-calling capabilities. ## Specific AI Coding Assistants Supported by Hallmark While Hallmark's architecture is intentionally generic, the repository specifically identifies the following AI coding assistants as tested and compatible: ### ChatGPT and OpenAI Models ChatGPT and other OpenAI models integrate with Hallmark via the generic skill-calling interface. The assistant can invoke Hallmark from a ChatGPT plugin or custom tool that calls the skill endpoint, treating the design system as an external capability. ### Claude (Anthropic) Claude's tool-calling capabilities can reference the Hallmark skill directly. According to the source analysis, Hallmark treats requests from Claude the same way as any other assistant, using the standardized skill invocation protocol defined in [`SKILL.md`](https://github.com/Nutlope/hallmark/blob/main/SKILL.md). ### Gemini (Google AI) Google's Gemini models can invoke Hallmark through their function-calling or tool-calling mechanisms. The integration follows the same pattern as other assistants, requiring only that the AI coding assistant can issue a skill-call to Hallmark's endpoint. ### Together AI Together AI receives special mention in the codebase because Hallmark's runtime is **powered by Together AI**. The [`package.json`](https://github.com/Nutlope/hallmark/blob/main/package.json) file contains the description: `"A design skill for AI coding assistants. Makes the UIs they generate look made, not generated. Powered by Together AI."` This means Together AI works natively with Hallmark's model endpoints, providing the underlying infrastructure while still adhering to the same skill-based interface used by other assistants. ### Other LLM-Based Coding Assistants Any AI coding assistant capable of issuing a JSON request to Hallmark's endpoint can use the design system. The [`site/index.html`](https://github.com/Nutlope/hallmark/blob/main/site/index.html) file reinforces this by describing Hallmark as encoding "the anti-slop consensus" for any AI coding assistant that supports skill calls. ## The Technical Foundation: SKILL.md and Runtime Configuration The compatibility with multiple AI coding assistants stems from the generic skill definition located at [`skills/hallmark/SKILL.md`](https://github.com/Nutlope/hallmark/blob/main/skills/hallmark/SKILL.md). This file contains the universal interface that all assistants use, making the system deliberately vendor-agnostic. The runtime characteristics are further defined in the project's metadata. As noted in [`package.json`](https://github.com/Nutlope/hallmark/blob/main/package.json) and repeated in [`site/index.html`](https://github.com/Nutlope/hallmark/blob/main/site/index.html) meta tags, Hallmark is "Powered by Together AI," which provides the inference backend while maintaining open compatibility with various AI coding assistant frontends. ## Summary - Hallmark supports **any AI coding assistant** that can invoke skills, including ChatGPT, Claude, Gemini, and Together AI. - The integration relies on a **generic skill architecture** defined in [`skills/hallmark/SKILL.md`](https://github.com/Nutlope/hallmark/blob/main/skills/hallmark/SKILL.md) rather than vendor-specific APIs. - **Together AI** powers the underlying runtime, but works alongside other AI coding assistants through the same interface. - The system is **future-compatible** with new AI coding assistants that implement skill-calling capabilities. ## Frequently Asked Questions ### Is Hallmark limited to specific AI coding assistant vendors? No. Hallmark is intentionally **assistant-agnostic**. The skill definition in [`skills/hallmark/SKILL.md`](https://github.com/Nutlope/hallmark/blob/main/skills/hallmark/SKILL.md) uses a generic interface that any LLM-based AI coding assistant can invoke, provided it supports skill or tool calls. ### How does Together AI power Hallmark compared to other assistants? While Hallmark works with multiple AI coding assistants, its runtime is specifically powered by Together AI infrastructure. The [`package.json`](https://github.com/Nutlope/hallmark/blob/main/package.json) description explicitly states the project is "Powered by Together AI," meaning Together provides the model inference backend, while other assistants interact with Hallmark through the skill interface. ### Can I use Hallmark with custom or self-hosted AI coding assistants? Yes. Any AI coding assistant capable of sending a JSON request to Hallmark's skill endpoint can use the design system. As long as your custom assistant implements skill-calling functionality, it can invoke the guidelines defined in [`SKILL.md`](https://github.com/Nutlope/hallmark/blob/main/SKILL.md) regardless of the underlying model or hosting environment. ### Where is the skill definition configured for AI coding assistants? The skill definition resides in [`skills/hallmark/SKILL.md`](https://github.com/Nutlope/hallmark/blob/main/skills/hallmark/SKILL.md) at the repository root. This file contains the universal interface that all AI coding assistants use to invoke Hallmark's design capabilities, making it the central configuration point for assistant integration.