Getting Started

Getting Started

NOTE: This page covers installing and using the hypha plugin conversationally. If you want to run the underlying CLI yourself, or work on the generation pipelines, see Hypha CLI and Developers Experience.

Prerequisites

• Claude Code.
• Windows only: Git for Windows, for Git Bash – the SessionStart hook is pinned to run under bash, so Claude Code reports a clear error naming the missing shell if it isn't installed.
• Recommended: jq – brew install jq, sudo apt install jq, or winget install jqlang.jq. The metamodel ships as a structural graph (knowledge/<tag>/metamodel/metamodel.json, ~8 MB) with inheritance closures precomputed. Set-shaped and cross-cutting questions – "which metaclasses have a feature typed by Expression", "every concrete subclass of Usage" – are one jq query against it. Without jq the skills fall back to reading the per-element markdown, which is slower and pulls more into context.

Install

1. Add the marketplace and install the plugin:

   /plugin marketplace add mycelium-cmbse/mycelium-hypha
   /plugin install hypha@mycelium
   

   /plugin list confirms it is installed, but installing only adds a SessionStart hook, and that hook only runs at session start, so nothing about SysML v2/KerML data happens yet.

2. Start a new session, or resume one (claude --resume / --continue) so the hook actually runs it does not fire mid-session. It quietly compares what is installed locally against what is offerable upstream and feeds the result into Claude's context as additionalContext; expect no visible output unless there is something to report. See Skills and Agents#the-sessionstart-hook for what it checks.

3. Ask it, for example, "what SysML v2 releases are available?" Claude will report that nothing is installed yet, name the releases available upstream, and ask which one to fetch – this is the first visible sign anything happened. Confirm a release, and it fetches and generates it for you (see The Knowledge Base and Hypha CLI).

4. Ask your real question. Metamodel lookup and validation work as soon as a release is installed; spec citation additionally needs the specification text generated locally, which hypha generate now does on its own once a release's OMG PDFs are fetched – no maintainer source checkout needed any more (see The Knowledge Base#spec).

Run /overview at any point for a fixed summary of Hypha's three capabilities with example prompts.

Example prompts

• Metamodel lookup: "What features does PartUsage own and inherit?", "How does ConnectionUsage relate to ConnectionDefinition?", or "Which metaclasses specialize Feature?"
• Model library lookup: "What does ISQBase::mass look like?", "Where is ScalarValues::Real defined?"
• Spec citation: "What does the SysML v2 spec say about conformance?" or "Quote the normative rule for redefinition."
• Validation: "Is this valid SysML v2? part def Vehicle { attribute mass : Real[2..1]; }"
• Release management: "What releases are available?", "Fetch the latest", "Switch to 2026-04", "Remove 2026-03".

Releases

KerML and SysML v2 are released on a rolling tag cadence (YYYY-MM), and Hypha generates its knowledge base per release tag. Nothing is pre-installed – the first thing a fresh install does is ask which release to fetch.

Manage this conversationally, in plain language, and Claude drives the underlying hypha CLI for you (check / discover / fetch / generate / use / remove). It always states what the current default release is, and asks before fetching (real time, real bandwidth) or removing (deletes that release's files for good). The skills state which release an answer came from, and answer from the default unless you name one.

See Hypha CLI if you would rather run these commands yourself.