Where to Find Hallmark's SKILL.md Definition: Complete Guide to the Design Skill Specification

Hallmark's SKILL.md definition is located at skills/hallmark/SKILL.md in the Nutlope/hallmark repository, containing the complete specification for invocation verbs, safety rails, and anti-slop design flows.

Hallmark is an open-source design skill that enforces rigorous quality standards when generating UI assets. According to the Nutlope/hallmark source code, every behavior, command pattern, and quality checkpoint is codified in a single authoritative document. Understanding where to find and how to read this specification is essential for anyone extending or invoking the skill.

SKILL.md Location and Structure

The definitive Hallmark skill definition resides in skills/hallmark/SKILL.md. This file serves as the contract between the skill and its consumers, specifying everything from version metadata to execution semantics.

You can access the canonical version directly on GitHub:

https://github.com/Nutlope/hallmark/blob/main/skills/hallmark/SKILL.md

The file is organized into functional sections that define:

• Skill identity — name, description, and version
• Usage verbs — how to invoke different operating modes
• Safety rails — constraints that prevent low-quality output
• Design flow — the step-by-step process Hallmark follows for all builds

Invocation Verbs Defined in SKILL.md

The SKILL.md specification defines four ways to invoke Hallmark, each mapped to a distinct execution path. These patterns are documented in the "How to use this skill" table within the file.

Default Design Flow

When no verb is specified, Hallmark executes its standard design pipeline:

hallmark <brief>

This triggers the complete flow: parse brief, apply macrostructures, generate assets, and run slop-tests.

Audit Mode

The audit verb performs anti-pattern detection on existing code:

hallmark audit ./src/pages/Homepage.tsx

This command invokes the rules defined in references/verbs/audit.md, checking for layout violations, accessibility gaps, and slop indicators.

Redesign Mode

The redesign verb regenerates an existing page with optional stylistic modifiers:

hallmark redesign ./src/pages/About.tsx --mood playful

The --mood flag maps to predefined aesthetic profiles in references/moods/. If omitted, Hallmark preserves the original intent while applying current best practices.

Study Mode

The study verb ingests external design references from URLs or local images:

hallmark study https://example.com
hallmark study ./screenshots/landing.png

This verb extracts structural patterns, color systems, and typographic scales for incorporation into Hallmark's knowledge base.

Supporting Reference Files

While SKILL.md contains the high-level contract, the implementation details are distributed across specialized files in references/. These are normatively referenced by the skill definition:

File Path	Purpose
skills/hallmark/SKILL.md	Core specification, verbs, and safety rails
references/verbs/audit.md	Detailed audit implementation rules
references/verbs/redesign.md	Detailed redesign implementation rules
references/verbs/study.md	Detailed study implementation rules
references/slop-test.md	Post-emit quality verification suite
references/macrostructures.md	Index of composable layout patterns

These files form a hierarchical specification: SKILL.md governs behavior, while reference files provide the executable detail.

Safety Rails and Quality Enforcement

A critical section of SKILL.md defines anti-slop design principles — mandatory checkpoints that block low-quality output. These include:

• Macrostructure validation — all generated layouts must derive from approved patterns in references/macrostructures.md
• Slop-test execution — every emit must pass the verification suite defined in references/slop-test.md
• Verb-specific constraints — each mode has hard limits on output scope and modification depth

These rails are not advisory; the skill implementation enforces them at runtime, rejecting non-compliant generations.

Version Tracking and Skill Evolution

SKILL.md includes semantic versioning that propagates to skill consumers. When Hallmark's design philosophy evolves — new macrostructures added, slop-tests refined, verbs extended — the version bump in SKILL.md signals breaking or additive changes to downstream systems.

Monitor this file's commit history to track:

• New verb additions
• Safety rail modifications
• Reference file reorganizations

Summary

• Primary location — skills/hallmark/SKILL.md contains the complete Hallmark skill specification
• Four invocation verbs — default, audit, redesign, and study, each with distinct parameters
• Distributed implementation — verb details live in references/verbs/, quality checks in references/slop-test.md
• Enforced constraints — anti-slop principles are binding, not optional
• Direct access — view the current version at github.com/Nutlope/hallmark/blob/main/skills/hallmark/SKILL.md

Frequently Asked Questions

What information does SKILL.md contain that isn't in other files?

SKILL.md holds the normative specification — the contract that defines valid skill behavior. While references/verbs/audit.md explains how auditing works, only SKILL.md declares that audit is a supported verb with specific syntax. It also bundles cross-cutting concerns: version, description, shared safety rails, and the complete "How to use" reference table.

Can I extend Hallmark by editing SKILL.md directly?

Yes, but with caveats. SKILL.md is the source of truth for skill behavior; modifications change what Hallmark considers valid. Adding a new verb requires updating the usage table in SKILL.md and creating the corresponding implementation file in references/verbs/. The skill runtime validates that declared verbs have matching reference implementations.

How do the mood flags in redesign mode work?

The --mood parameter maps to aesthetic profile files in references/moods/ (e.g., playful.md, minimal.md, corporate.md). SKILL.md defines the flag's syntax and valid values; the referenced files contain the concrete design tokens — color palettes, radius scales, motion curves — that Hallmark injects during redesign. Invalid mood values trigger a validation error before any generation begins.

What's the relationship between slop-tests and SKILL.md?

SKILL.md mandates slop-test execution; references/slop-test.md defines the tests. This separation of policy from implementation lets the Hallmark team iterate on quality criteria without changing the skill contract. When new anti-patterns are discovered, they get added to slop-test.md and immediately apply to all future Hallmark runs, regardless of verb or invocation mode.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}