HVE Core is a collection of agents, prompts, coding instructions, and skills for building repeatable software-development workflows with GitHub Copilot. It is intended for individuals and teams that want structured AI-assisted research, planning, implementation, and review, while the catalogue entries provide many of its reusable workflow components.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add microsoft/hve-core --skill c4-architecturegit clone --depth 1 https://github.com/microsoft/hve-coreWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/microsoft/hve-core/c4-architecture)<a href="https://agentmods.dev/skills/microsoft/hve-core/c4-architecture"><img src="https://agentmods.dev/badge/skills/microsoft/hve-core/c4-architecture/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/microsoft/hve-core/c4-architecture"><img src="https://agentmods.dev/badge/skills/microsoft/hve-core/c4-architecture.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Prompt Injection · line 78 Large whitespace padding was detected (a block of blank lines or a long run of spaces). This can push injected instructions below or to the right of the visible area so a human reviewer never sees them while the agent still reads them. Manual review of the hidden content is recommended.Fix: Remove the large whitespace padding (blank-line blocks or long space runs) and review any content hidden below or to the right of it. Keep skill files compact and reviewable so no instructions can be
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00063 | $0.01235 |
| Opus 5.5 | $0.00025 | $0.00494 |
| Sonnet 5.5 | $0.00013 | $0.00247 |
| Haiku 4.5 | $0.00006 | $0.00123 |
Grade A, and why
c4-architecture scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 83 lines — stays where its author put it; the contents beside it link to each section on GitHub.
C4 Architecture Skill
Goal
Produce audience-appropriate C4 diagrams for existing systems from code or planned systems from requirements. Create new diagrams with the selected renderer, or update existing diagrams when their renderer is supported.
Supported Diagrams
These defaults apply when creating new diagrams. Updates change only what the request targets.
| Diagram | Generated by default | User selection | Answers |
|---|---|---|---|
| Level 1: System Context | Yes | Which system when several qualify | Who uses the system and what does it interact with |
| Level 2: Container | Yes | None | What separately deployable or runnable units make up a system |
| Level 3: Component | Yes | Which containers when several qualify | What major building blocks sit inside one container |
| Level 4: Code | On request only | Which component to detail | How one component maps to code structures |
| Deployment | Offered when evidenced | Opt-in and which environment | Where container instances run in one named environment |
Supported Renderers
Read the selected renderer reference in full before generating or modifying diagrams. Apply every relevant rule.
| Renderer | Reference | Status |
|---|---|---|
mermaid |
references/renderer-mermaid.md | Default |
Process
Follow these steps when activating this skill:
- Ensure the renderer required by the user is available.
- Inspect the relevant code and documentation to identify architecture elements, boundaries, relationships, and deployment evidence.
- Read and apply the C4 modelling instructions, including its modelling-uncertainty decision.
- When creating new diagrams, identify which diagrams, systems, and levels are required. Ask the user to clarify if unclear from context.
- When updating an existing diagram document, read the complete document first and apply only the requested model delta. Preserve existing nodes, relationships, comments, layout controls, and stable identifiers unless the requested change affects them. Ask the user before removing content whose relevance is uncertain.
- Before responding, validate each created/edited diagram rule by rule against the selected renderer reference and correct every violation.
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2mo ago First seen · 83 lines · 63 tokens per session scan A b100a480b723
c4-architecture is a skill published in the GitHub repository microsoft/hve-core (1,606 stars, last pushed today), licensed MIT. It adds 63 tokens to every session and 1,235 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
c4-architecture compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| c4-architecturemicrosoft/hve-core | Skill | 1.6k | today | MIT | A | 63 | Claude Code |
| mem0-oss-to-platformmem0ai/mem0 | Skill | 69k | 2d ago | Apache-2.0 | A | 217 | Claude Code, Codex |
| azure-mgmt-botservice-dotnetmicrosoft/skills | Skill | 3.2k | 2d ago | MIT | A | 78 | Claude Code |
| fastapi-router-pymicrosoft/skills | Skill | 3.2k | 2d ago | MIT | A | 46 | Claude Code |
| api-designericrisco/rsc-harness | Skill | 555 | 4d ago | MIT | A | 105 | Claude Code, Codex |
| migrate-segw-to-raparc-mcp/arc-1 | Skill | 253 | yesterday | MIT | A | 106 | Claude Code |
| telnyx-messaging-hosted-curlteam-telnyx/ai | Skill | 225 | today | MIT | A | 45 | Claude Code |