sysml-validation

sysml-validation is a skill for Claude Code from mycelium-cmbse/mycelium-hypha. It costs 71 tokens per session (1,546 once invoked), scanned A, original, Apache-2.0.

A validator for SysML v2 and KerML text files, which are textual languages for writing system models. It checks .sysml and .kerml notation against the language grammar and metamodel.

In plain words
What is it for?
Use it to validate model snippets or files, identify errors and their locations, and get corrections for constructs that do not match the selected language release.
Why use it?
It catches invalid syntax and structural violations and explains what needs to change, reducing trial-and-error when writing models.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions subagents.

Part of the hypha plugin — 5 skills, 1 command, 3 agents shipped together

Good fit Use it to validate model snippets or files, identify errors and their locations, and get corrections for constructs that do not match the selected language release.

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Install with agentmods
npx agentmods add skills/mycelium-cmbse/mycelium-hypha/sysml-validation
Install

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.

Any agent
npx skills add mycelium-cmbse/mycelium-hypha --skill sysml-validation
Clone the repo
git clone --depth 1 https://github.com/mycelium-cmbse/mycelium-hypha

Made for: Claude Code.

Or install hypha, the plugin that ships this one along with the rest of its 5 skills, 1 command, 3 agents.

Wrote 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.

agentmods badge for sysml-validation

README.md
[![agentmods](https://agentmods.dev/badge/skills/mycelium-cmbse/mycelium-hypha/sysml-validation.svg)](https://agentmods.dev/skills/mycelium-cmbse/mycelium-hypha/sysml-validation)
Your own site
<a href="https://agentmods.dev/skills/mycelium-cmbse/mycelium-hypha/sysml-validation"><img src="https://agentmods.dev/badge/skills/mycelium-cmbse/mycelium-hypha/sysml-validation.svg" alt="Measured on agentmods" height="20"></a>
Per session 71 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,546 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00071 $0.01546
Opus 5 $0.00036 $0.00773
Sonnet 5 $0.00014 $0.00309
Haiku 4.5 $0.00007 $0.00155

Measured 8d ago against content hash fb858e5d8ff7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

sysml-validation 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 8d 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.

skills/sysml-validation/SKILL.md · 115 lines

How it starts

The opening of the file, as written. The whole thing — 115 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SysML v2 validation

Check SysML v2 / KerML textual notation against the documented grammar and metamodel, then report findings with locations and corrections.

Releases

The metamodel and grammar are generated per upstream release tag (YYYY-MM). Read knowledge/versions.json for the installed tags and the default one, then substitute it for <tag> below. Validate against the default release unless the user names another, and say which release you validated against — a construct valid in one release may not be in another.

Knowledge base

  • knowledge/<tag>/textual-notation/index.md – the keyword reference, read from that release's own grammar. Start here for what is and is not a keyword.
  • knowledge/<tag>/textual-notation/examples/ – every model shipped with that release, copied verbatim, each linked to the metamodel elements it declares. These are the reference for what valid notation looks like: if a construct appears here, it is valid for this release.
  • knowledge/<tag>/metamodel/ – the combined KerML + SysML v2 metamodel: elements/<Metaclass>.md for structural constraints, index.json (or index.md) for fast name → element lookup, and metamodel.json for the structural checks below.
  • knowledge/<tag>/cross-references.json – element → clause identifiers, BNF production and worked example. Committed, so it works without the PDFs.
  • knowledge/<tag>/spec/ – normative clauses to cite. Git-ignored / generated locally (see tools/spec-extract); if it is empty, cite the metamodel/grammar and name the governing clause from cross-references.json rather than inventing one.

What to check

Syntax (against the grammar reference)

  • Every declaration is terminated by ; or has a { } body; braces/brackets/parentheses balance.
  • Names are not reserved keywords unless quoted ('name'); keywords are spelled and placed per the reference.
  • Relationship operators are correct: : (typing / defined by), :> (specializes / subsets), :>> (redefines), ::> (references), => (crosses). = binds a value, not a type.
  • Multiplicity is well-formed ([lower..upper], [n], [*]).

Read the full file on GitHub · 115 lines

Changes

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.

  1. 8d ago First seen · 115 lines · 71 tokens per session scan A fb858e5d8ff7

Subscribe to this mod's changes

sysml-validation is a skill published in the GitHub repository mycelium-cmbse/mycelium-hypha (11 stars, last pushed yesterday), licensed Apache-2.0. It adds 71 tokens to every session and 1,546 once invoked, about $0.0004 per session on Opus 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 2026-08-31.

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