dsh-unreal-engine-skills

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Unofficial DeepSeek Harness port of Epic Games' Unreal Engine Skills for Claude Code (MIT, upstream 3.1.1). One bundle gives an agent three things:

• Three runtime skills. unreal-mcp (discover and call Editor toolsets), create-toolset (author AI-callable C++/Python toolsets) and unreal-skill (author UE Agent Skills inside the editor), registered from skills/.
• The Unreal MCP connection. A unreal-mcp row using @deepseek-ai/dsh-mcp-client connects to the editor's ModelContextProtocol server (default http://127.0.0.1:8000/mcp). The port and URL path are editable on the Harness Plugins page and take effect on save, without restarting.
• Unreal project context. When a session's working directory is inside an Unreal project, a short UE-specific context note is added to the system prompt (the directory is detected by walking upward for a .uproject or GenerateProjectFiles.*).

Current version: 1.0.8. See Status and verification boundary for what has and has not been verified.

Install

Requires DeepSeek Harness >=0.2.0-rc.2 <0.3.0 (declared as engines.dsh in package.json).

From GitHub

dsh plugin --profile <your-profile> add github:liuli-zsl/dsh-unreal-engine-skills

For dsh web, use the web profile. On the official Desktop app, prefer the app's Plugins page and enter the GitHub source there. Command-line management of desktop requires the command installed by Desktop, an initialized profile, and fully quitting the app first; the npm CLI cannot manage that profile. See the official CLI reference. The bundle patch adds two loader rows: unreal-engine-skills (this package) and unreal-mcp (@deepseek-ai/dsh-mcp-client).

From the plugin market

This plugin is planned for submission to the community catalog used by dshmarket; it is not yet listed. After acceptance, users of that catalog can search for "Unreal Engine Skills". Harness 0.2.1+ also supports this catalog in Plugins → Discover → Index sources; it must be added there if not already configured. See docs/publishing.md for the source and submission.

From a local checkout (development)

Point the Harness plugin manager's install_bundle at this directory, or add the directory with dsh plugin add. When installed as a link to this checkout, run pnpm install --frozen-lockfile here first: the host-side dependency (@deepseek-ai/schemastery) must be present in this repository's node_modules, otherwise the plugin row silently stays inactive and none of the skills, context injection or port form work.

Editor setup (once per project)

Your engine build must actually contain the ModelContextProtocol and AllToolsets plugins. This package does not install them, and does not claim support for every UE5 release. The exact engine version/branch and Windows/Linux behavior have not yet been recorded as verified.

1. Enable the ModelContextProtocol and AllToolsets plugins in the project's .uproject. Without AllToolsets the server starts but exposes no tools.
2. Start the MCP server when the editor runs: either set bAutoStartServer=True under [/Script/ModelContextProtocolEngine.ModelContextProtocolSettings] in <Project>/Saved/Config/<Platform>Editor/EditorPerProjectUserSettings.ini, or run ModelContextProtocol.StartServer [port] in the editor console.
3. The default port is 8000.

Port configuration

• Plugins page form (recommended). Port and URL path are volatile config of the unreal-engine-skills row. Saving goes through Harness settings (settings.mutate → configEditor.edit); the host half then synchronizes the unreal-mcp row's url to http://127.0.0.1:<port><path> and the MCP client reconnects, without a restart. The sync runs both for a settings save (the Loader announces committed volatile changes) and after a plugin reload, and writes only when the url actually changes. It preserves current explicit settings (including headers, timeouts and reconnect policy), with bundle defaults for fields that have not been overridden (failOnStartupError, 300 s tool timeout, ~1 h backoff reconnect budget). On a Harness build that does not announce volatile updates, a saved endpoint takes effect on the next reload or restart.
• Valid input. Port must be an integer from 1 to 65535. The path must start with /, contain no spaces, backslashes, query or fragment, and use percent encoding for characters outside the RFC 3986 path set (for example /mcp%20endpoint). Both the form and host schema validate it.
• Environment variable. UNREAL_MCP_URL=http://127.0.0.1:9999/mcp set before starting Harness. It is process-wide (restart required) and always takes precedence over the form.
• Custom transport guard. If you change the unreal-mcp row to a stdio proxy (transport: stdio with command/args), the port sync leaves that row untouched.
• Patch entry caveat. In a profile patch, an entry with the same id replaces the row's config instead of merging. A hand-written patch must repeat serverName / transport / url; writing only url fails schema validation and the plugin will not activate. Prefer the form or the environment variable.
• The sync relies on the HMR transaction around configEditor.edit(): it escapes the nested transaction check with hmr.executing.exit() and runs on the HMR queue (HMR transactions cannot be nested is a design constraint, not a defect).

Verify

With the editor running, ask the agent to call mcp__unreal-mcp__list_toolsets (or "list all actors in the current level"). On the Plugins page the unreal-mcp row should be running, and the editor output log should show the MCP server startup message.

Security

The bundle gives an agent broad live access to a running editor, including ProgrammaticToolset.execute_tool_script (arbitrary Python inside the editor process). Treat it like "letting an assistant run arbitrary code". Commit or shelve before long MCP sessions and review the diff afterwards. The upstream README has the full threat model.

Status and verification boundary

Version 1.0.8 has automated Node tests for schema validation, preservation of custom MCP settings, environment-variable precedence, transport protection, HMR transaction escape, skill registration, project context, and the volatile-settings sync path. Browser tests evaluate the actual bundle against shared-primitives contract shims; they do not render the real Harness UI.

Earlier releases were checked online against DeepSeek Harness 0.2.1-rc.2: schema visibility, port sync, client bundle delivery and slot registration. Those historical results are recorded in CHANGELOG.md and are not a fresh acceptance of 1.0.8.

Live verification of 1.0.6 confirmed the form, the invalid-value blocking and the settings write, but found that a saved endpoint did not reach the MCP row until a restart; 1.0.7 fixed that and the save flow was re-checked live on 2026-10-21: a 9999 → 8000 save updated unreal-mcp.url in the same process, with no restart and no write loop. Still required for 1.0.8: a clean-profile install and a successful read-only tool call against a running editor. The sync depends on DSH internals (configEditor, the HMR queue, hmr.executing.exit(), loader/volatile-update); re-check after DSH upgrades. Evidence is recorded in CHANGELOG.md.

Repository layout

Path	Purpose
package.json	Package manifest: dsh.bundle.patch, dsh.client (browser half and its inject modules), exports["./client"], and the engines.dsh compatibility range.
cordis.patch.yml	Bundle patch layer: inserts the unreal-engine-skills row and the unreal-mcp row (whose url defaults to UNREAL_MCP_URL via a !!js expression).
lib/index.js	Host half: skill registration from skills/, Unreal project detection and system-prompt context injection, the volatile Config (port, path) and the url sync.
lib/client.js	Browser half: a hand-written __ModuleLoader__.load bundle (no build step) rendering the port form on the bundle page and the "Configure" entry on the unreal-mcp row.
skills/	The three skills' SKILL.md files and the unreal-mcp reference documents (setup.md, operations.md).
locale/	Localization dictionaries.
docs/publishing.md	Release, npm and plugin-market submission steps.
LICENSE, THIRD_PARTY_NOTICES.md	License and upstream attribution.

Related projects

• EpicGames/unreal-engine-skills-for-claude-code-plugin — the upstream Claude Code plugin (MIT). This repository is a port of it.
• PeterTXPan/dsh-unreal-mcp — another unofficial DeepSeek Harness bundle for the Unreal MCP server, independently maintained. This project differs in its plugin-page port form with hot reload and its targeting of the current 0.2.x Harness line; the two can be evaluated independently.

Development

There is no build step. Repo conventions (version bump, documentation sync, verification scope) are in AGENTS.md; changes are recorded in CHANGELOG.md. Publishing and marketplace steps are in docs/publishing.md.

Run pnpm install --frozen-lockfile --ignore-scripts, then pnpm test. The tests use Node's built-in runner and do not compile code. The CI workflow runs the same checks on Node 22 and 24; its remote result must be checked after pushing.

License

MIT © 2026 liuli-zsl. Adapted skill material retains Epic Games' MIT notice; see THIRD_PARTY_NOTICES.md. Unreal Engine is a trademark of Epic Games, Inc. This project is unofficial and is not affiliated with or endorsed by Epic Games.