AI Artifacts Architecture

HVE Core provides a four-tier artifact system for customizing GitHub Copilot behavior. Each tier serves a distinct purpose in the delegation chain, enabling structured, reusable AI guidance that flows from user intent to technology-specific standards and executable utilities.

Artifact Type Hierarchy

The artifact system organizes customizations by scope and responsibility. Prompts handle user interaction, agents orchestrate workflows, instructions encode standards, and skills provide executable utilities.

Prompts

Prompts (.prompt.md) serve as workflow entry points. They capture user intent and translate requests into structured guidance for Copilot execution.

Core Characteristics

• Define single-session workflows with clear inputs and outputs
• Accept user inputs through ${input:varName} template syntax
• Delegate to agents via agent: frontmatter references

Frontmatter Structure

---
description: 'Protocol for creating ADO pull requests'
agent: RPI Agent
---

Prompts answer the question "what does the user want to accomplish?" and route execution to appropriate agents.

Agents

Agents (.agent.md) define task-specific behaviors with access to Copilot tools. They orchestrate multi-step workflows and make decisions based on context.

Core Characteristics

• Specify available tools through tools: frontmatter arrays
• Enable workflow handoffs via handoffs: references to other agents
• Maintain conversation context across multiple interactions
• Apply domain expertise through detailed behavioral instructions

Frontmatter Structure

---
description: 'Orchestrates task planning with research integration'
tools: ['codebase', 'search', 'editFiles', 'changes']
handoffs:
  - label: "Coordinate RPI Work"
    agent: RPI Agent
    prompt: "Coordinate this task through the applicable RPI phases"
    send: true
---

Agents answer the question "how should this task be executed?" and coordinate the necessary tools and resources.

Instructions

Instructions (.instructions.md) encode technology-specific standards and conventions. They apply automatically based on file patterns and provide consistent guidance across the codebase.

Core Characteristics

• Match files through applyTo: glob patterns for automatic application
• Define coding standards, naming conventions, and quality requirements
• Apply to specific languages, frameworks, or file types
• Stack with other instructions when multiple patterns match

Frontmatter Structure

---
description: 'Python scripting standards with type hints'
applyTo: '**/*.py, **/*.ipynb'
---

Instructions answer the question "what standards apply to this context?" and ensure consistent code quality.

Repo-Specific Instructions

Instructions placed at the root of .github/instructions/ (without a subdirectory) are scoped to the hve-core repository itself and MUST NOT be included in marketplace package membership. These files govern internal repository concerns (CI/CD workflows, repo-specific conventions) that are not applicable outside the repository. Root-level artifacts are intentionally excluded from artifact selection and package composition.

IMPORTANT

Root-level files under .github/instructions/ (no subdirectory) are repo-specific and never distributed. Files in subdirectories like hve-core/, ado/, and shared/ are package-scoped and distributable.

Skills

Skills (.github/skills/<name>/SKILL.md) provide executable utilities that agents invoke for specialized tasks. Unlike instructions (passive reference), skills contain actual scripts that perform operations.

Core Characteristics

• Provide self-contained utility packages with documentation and scripts
• Include parallel implementations for cross-platform support (.sh and .ps1)
• Execute actual operations rather than providing guidance

Directory Structure (by Convention)

.github/skills/{package-id}/<skill-name>/
├── SKILL.md           # Required entry point with frontmatter
├── scripts/
│   ├── convert.sh     # Bash implementation
│   └── convert.ps1    # PowerShell implementation
└── examples/
    └── README.md      # Usage examples

Frontmatter Structure

---
name: video-to-gif
description: 'Video-to-GIF conversion with FFmpeg optimization'
---

Required Frontmatter Fields

Field	Description
name	Lowercase kebab-case identifier matching directory name
description	Brief capability description

Maturity is component metadata in .github/plugin/marketplace.json, not skill frontmatter. See Marketplace Identity.

Skills answer the question "what specialized utility does this task require?" and provide executable capabilities beyond conversational guidance.

Key Distinction from Instructions

Aspect	Instructions	Skills
Nature	Passive reference	Active execution
Content	Standards and conventions	Scripts and utilities
Activation	Automatic via glob patterns	Explicit invocation
Output	Guidance for Copilot	Executed operations

Delegation Flow

The artifact system follows a hierarchical delegation model. User requests flow through prompts to agents, which apply relevant instructions during execution.

graph LR
    USER[User Request] --> PROMPT[Prompt]
    PROMPT --> AGENT[Agent]
    AGENT --> INSTR[Instructions]
    AGENT --> SKILLS[Skills]

Flow Mechanics

1. User invokes a prompt through /prompt commands or workflow triggers.
2. Prompt references an agent via agent: frontmatter, delegating execution.
3. Agent executes with instructions auto-applied based on file context.
4. Agent invokes skills for specialized utilities with executable scripts.

This delegation model separates concerns. Prompts handle user interaction, agents manage orchestration, and instructions provide standards.

Interface Contracts

Each artifact type defines clear interfaces for interoperability.

Prompt-to-Agent References

Prompts reference agents through the agent: frontmatter field:

---
description: 'Create a pull request with work item linking'
agent: 'pr-creator'
---

The referenced agent file (pr-creator.agent.md) is typically organized under .github/agents/{package-id}/ by convention. When a user invokes the prompt, Copilot activates the specified agent with the prompt's context.

Instruction Glob Patterns

Instructions use applyTo: patterns for automatic activation:

Pattern	Matches
**/*.py	All Python files recursively
**/tests/**/*.ts	TypeScript files in test directories
**/.copilot-tracking/pr/**	PR tracking files

Multiple instructions can apply to the same file. When patterns overlap, all matching instructions contribute guidance. Pattern specificity determines precedence for conflicting directives.

Skill Entry Points

Skills provide self-contained utilities through the SKILL.md file:

.github/skills/{package-id}/<skill-name>/
├── SKILL.md                    # Entry point documentation
├── convert.sh                  # Bash implementation
├── convert.ps1                 # PowerShell implementation
└── examples/
    └── README.md

The {package-id} path segment reflects the conventional organization; artifacts can reside in any subfolder.

Copilot discovers skills automatically when their description matches the current task context. Skills can also be referenced explicitly by name. The skill's SKILL.md documents prerequisites, parameters, and usage patterns. Cross-platform scripts ensure consistent behavior across operating systems.

Marketplace Identity

.github/plugin/marketplace.json is the sole distribution authority. Every active plugins[] entry is an ordinary, self-contained recipe whose standard agents, commands, rules, skills, and optional hooks fields declare membership. The x-hve overlay carries display metadata, component lifecycle maturity, a documentation path, and optional profiles.

hve-core is the focused package for RPI workflows, HVE Builder, Git operations, and code review. hve-core-all is the full bundle of active content and the only package that declares the starter profile. Domain and utility packages provide narrower capability sets. The catalog remains authoritative for active package names, memberships, maturity, and documentation.

Shared Projection

Catalog membership is relative to the canonical .github source root: agents/*.agent.md, prompts/*.prompt.md, instructions/*.instructions.md, skills/* directories, and hooks/*.json. MarketplaceHelpers.psm1 applies lifecycle policy and closes transitive agent handoffs over those paths. Plugin generation and VSIX preparation consume the same resolved source set before mapping it to a host-specific package layout. Unresolved or ambiguous handoffs fail validation.

Lifecycle Labels and Channels

Lifecycle label	Stable Channel	PreRelease Channel
stable	Included	Included
preview	Included	Included
experimental	Included	Included
deprecated	Excluded	Excluded
removed	Excluded	Excluded

Component maturity defaults to stable. The label discloses lifecycle posture and informs governance; it does not select a release channel. Stable and PreRelease contain the same active package-name set and the same active component and maturity projection for each package. Removed component tombstones may remain in x-hve.componentMaturity after active membership is removed so policy checks retain the retirement record.

Self-Contained Outputs

Every plugin and VSIX contains the complete resolved projection for its catalog entry. The architecture does not use package dependencies, aggregate metadata, extensionPack, or extensionDependencies to compose advertised content.

Extension Integration

The VS Code extension discovers and activates AI artifacts through contribution points.

Discovery Mechanism

The extension scans these directories at startup:

• .github/prompts/{package-id}/ for workflow entry points
• .github/agents/{package-id}/ for specialized behaviors
• .github/instructions/{package-id}/ for technology standards
• .github/skills/{package-id}/ for utility packages

These paths reflect the conventional directory structure. Artifact inclusion is controlled by standard component paths in .github/plugin/marketplace.json. Root-level artifacts (files directly under .github/{type}/ with no subdirectory) are repo-specific, excluded from discovery, and never packaged into extension builds.

The lifecycle table above applies equally to extension contributions. Stable and PreRelease differ in source ownership, cadence, and version, not component membership.

Extension Identities

Each active catalog entry projects to one Copilot plugin root and one VSIX identity. The focused hve-core entry retains the unsuffixed HVE Core extension identity, ise-hve-essentials.hve-core. Other entries use deterministic package-specific identities in the same publisher namespace, ise-hve-essentials.hve-<package-name>. These identities are generated from catalog package names and do not indicate that publication has occurred.

The VS Code extension is prepared with Prepare-Extension.ps1 and packaged with Package-Extension.ps1. Copilot package assembly materializes regular-file packages only under a caller-supplied absolute staging root outside the repository. Set HVE_PLUGIN_STAGING_ROOT before running npm run plugin:generate, or pass -StagingRoot directly to Generate-Plugins.ps1. Ordinary validation does not generate a repository-root plugins/ tree.

Choose the catalog entry that matches the required scope. Do not install hve-core and hve-core-all together because their content overlaps. Both plugin entries include the telemetry hook. VS Code has no declarative hook contribution point, so extension users configure hook locations manually.

For a repository-owned selection, the installer requires an exact PackageName before it resolves a profile or component. The starter profile belongs only to hve-core-all. It copies agents, prompts, instructions, and complete skill directories while preserving repository-relative paths; hooks are not copied.

Activation Context

Instructions activate based on the current file's path matching applyTo: patterns. Prompts and agents activate through explicit user invocation. Skills activate when agents or users request their utilities.

The extension provides these contribution points:

• /prompt <name> invokes prompts by filename.
• Agents activate through prompt references or direct invocation.
• Matching instructions inject into Copilot context automatically.

Deprecated Artifacts

Artifacts that have been superseded or are scheduled for removal live under .github/deprecated/{type}/, preserving the same type subdirectories used by active artifacts.

Location

.github/deprecated/
├── agents/         # Superseded agent files
├── instructions/   # Retired instruction files
├── prompts/        # Retired prompt files
└── skills/         # Retired skill packages

Automatic Exclusion

The build system excludes .github/deprecated/ contents from all downstream surfaces:

Surface	Exclusion Mechanism
Marketplace packages	Catalog membership and source containment
Plugin generation	Get-ArtifactFiles path filter
Extension packaging	Discovery function deprecated path filter
VS Code activation	Not discovered at runtime

Remove deprecated paths from marketplace membership when an artifact moves to .github/deprecated/. The path-based exclusion operates independently of maturity metadata, providing a reliable safety net against silent reintroduction.

Retention and Removal

Deprecated artifacts remain in the repository for traceability and migration guidance. Each deprecated file SHOULD contain a frontmatter note or heading that identifies its replacement. Permanent removal occurs at a planned retirement window with a corresponding changelog entry.

When to Deprecate

Move an artifact to .github/deprecated/{type}/ when:

• A newer artifact fully replaces its functionality
• The artifact is no longer maintained or tested
• The artifact targets a retired platform or workflow

Removed Artifacts

The removed maturity is an x-hve.componentMaturity tombstone keyed by a .github-root-relative canonical component path. It removes an artifact from every generated distribution while retaining policy history without adding maturity to artifact frontmatter.

To reactivate an artifact, restore its standard membership path, remove or change the tombstone, regenerate plugin and extension outputs, and run marketplace validation. The validator requires non-vacuous tombstone coverage and complete active-membership coverage for each applicable package recipe.

Mechanism	Signal	Distribution behavior
deprecated maturity	Sunset in progress	Excluded from both channels
removed tombstone	Withdrawn from distribution	Excluded while policy history remains
.github/deprecated/ path	Archived source	Excluded by source containment rules

Related Documentation

• Agent Systems Catalog - Overview of all agent systems with workflow documentation
• AI Artifacts Common Standards - Quality requirements for all artifacts
• Contributing Prompts - Prompt file specifications
• Contributing Agents - Agent file specifications
• Contributing Instructions - Instruction file specifications
• Contributing Skills - Skill package specifications

🤖 Crafted with precision by ✨Copilot following brilliant human instruction, then carefully refined by our team of discerning human reviewers.