Hypha – SysML v2 and KerML

Ask GitHub Copilot about SysML v2 and KerML using knowledge from a specific OMG release, rather than relying on general model knowledge. Hypha looks up metamodel elements and standard-library declarations on your machine and gives Copilot source links to cite in its answers.

What you can do

• Explore the metamodel – ask about elements such as PartUsage, their features, inheritance, operations and constraints.
• Find standard-library declarations – look up names such as ScalarValues::Real.
• Know which release answers your question – check the default release and whether its generated knowledge is available.
• Keep working across folders – installed knowledge is shared across workspaces on the same VS Code host.

Hypha is a preview, published as a pre-release for Windows x64 and for Linux x64 and arm64 (including WSL and SSH remotes).

Get started

You need VS Code 1.100 or later and access to GitHub Copilot Chat with tools enabled. Use a trusted local or remote workspace; browser-based VS Code and virtual workspaces are not supported.

1. Install Hypha – SysML v2 and KerML from the Extensions view, or a VSIX for your platform with Extensions: Install from VSIX…. In WSL or SSH, install it on the remote host where your workspace runs. You do not need to install .NET, Python, a separate CLI or an Agent Plugin.
2. Open the Command Palette (Ctrl+Shift+P, or Cmd+Shift+P on macOS) and run Hypha: Install a SysML v2 Release.
3. Choose a release and confirm the download and generation. It becomes the default only after generation succeeds. The first installation needs internet access and may take several minutes. The first specification generation may also download uv, a managed Python build and the extraction dependencies pinned by Hypha.
4. Run Hypha: Show Installed Releases to check readiness. Installation progress and the data location appear in the Hypha output channel.

If you previously installed the checkout-based Hypha Agent Plugin, disable it in VS Code while using this extension to avoid competing instructions or different data locations.

Use Hypha in Copilot Chat

1. Open Copilot Chat and select Agent mode.
2. Open Configure Tools near the chat input.
3. Search for Hypha and enable Hypha Release Status and Hypha Grounded Knowledge Lookup if they are not already checked.
4. Type #hypha in the chat input to select a tool, or use one of the prompts below.

Check the release and readiness

Use #hyphaReleaseStatus to report the default release and artifact readiness.
Do not fetch or generate anything.

Explore a metamodel element

Use #hyphaLookup to explain PartUsage from the default release's metamodel.
Cite the release and source; follow pagination as needed.

Find a standard-library declaration

Use #hyphaLookup to find ScalarValues::Real in the default release's model library.
Cite the release and source, not general knowledge.

Answers should identify the release and include clickable source links. Long source pages are returned in sections; Copilot can request the next section. If a name is ambiguous, Hypha returns matching names rather than choosing one arbitrarily. You can also ask for a particular installed release instead of the default.

Both tools are read-only: invoking them never downloads inputs or generates knowledge.

Commands

Run these commands from the Command Palette:

Your knowledge stays available across workspaces

Hypha stores downloaded inputs, generated knowledge and managed runtime caches in VS Code's extension-global storage, not in your modeling workspace. Opening another folder on the same host uses the same installed releases.

Windows, WSL, SSH hosts and other machines have separate storage; releases are not synchronized between them. You can find the storage location with Hypha: Show Installed Releases.

Uninstalling and stored data: Uninstalling Hypha may leave downloaded releases, generated knowledge and runtime caches on disk. Reinstalling can reuse this data. Hypha can remove individual releases, but provides no command to clear all stored data. Use Hypha: Show Installed Releases to find the data location.

The extension contains its runtime and extraction code, but no release knowledge, specification PDFs or extracted specification text. With your confirmation, installation downloads upstream inputs and generates knowledge locally. It may also download uv, a matching Python and extraction dependencies. Source excerpts returned to Copilot are included in its chat context.

Readiness and troubleshooting

• No installed release: run Hypha: Install a SysML v2 Release.
• Core artifacts are incomplete: installation may have been interrupted. Run installation again for the same release; existing downloaded inputs are reused.
• Normative specification text is missing: core lookups can still work. Check the Hypha output channel for extraction or download problems, then retry installation for the same release.
• Generation cannot download its runtime: the first specification generation needs access to the download sources for uv, managed Python and the pinned extraction dependencies. If a download fails or the machine is offline, generation reports the failure in the Hypha output channel and the new release does not become the default; retry when those sources are reachable.
• A release-operation lock prevents changes: wait for the other window to finish and retry. If a lock or its recovery was interrupted and the error persists, close all Hypha windows and ensure no Hypha processes are running before removing the named lock file from the data location.
• Tools are not listed: check that Hypha is enabled on the current workspace host, reload the window and open a new Agent chat. Check Configure Tools again.
• Windows: a path is too long: Hypha's data sits under %APPDATA%\Code\User\globalStorage\mycelium-cmbse.mycelium-hypha\, and its deepest files – a generated example page and files inside the managed Python – add up to about 165 characters. With a long Windows user name (about 18 characters or more), or with VS Code Insiders, whose folder name is longer, some paths go past Windows' classic 260-character limit. Hypha's CLI, uv and VS Code handle long paths, but other tools may not. If extraction, or opening a cited file, fails with a path-length error, turn on Windows' long path support (the LongPathsEnabled setting, which needs administrator rights), then retry installation for the same release.

A manifest entry alone does not mean generation finished. Status checks report artifact presence, not a full integrity check.

Current limits

• Hypha supports SysML v2 and KerML, not UML.
• Lookups provide source-backed knowledge, not compiler validation of your models.
• The lookup tool reads metamodel and model-library sources; it does not search or quote normative specification text, even when that text is installed.
• Hypha is published for Windows x64 and Linux x64/arm64, where it has been validated end to end. macOS x64/arm64 packages build but have not been validated yet, and are not published.
• On Windows, some paths in Hypha's data can exceed 260 characters for long user names or VS Code Insiders; see Windows: a path is too long above.

For feedback and source code, visit the Hypha repository.