Extensions
Install harnesses, MCP servers, skills, and agents from local directories, zip files, or git URLs.
Extensions add capabilities to nui via a manifest (extension.yaml) and contribution list files. Installed extensions live in ~/.nui/extensions/<name>/.
Full developer reference: Extension API documentation — manifest schema, harness SDK, HITL, storage, deployers, and worked examples.
Install
nui extension add ./my-extension
nui extension add https://github.com/example/my-extension.git
nui extension list
nui extension remove my-extension
Manage installed extensions from Settings → Extensions, or disable individual extensions without uninstalling.
Contribution types
| Contribution | Description |
|---|---|
harnesses |
stdio, TCP, or HTTP harness agents |
aiAssets.mcpServers |
Custom command-tool MCP servers |
aiAssets.skills / rules |
Bundled skills and instruction files |
catalog |
Discoverable MCP servers and skills |
agents |
ADL agent definitions |
mentionProviders |
@-mention autocomplete sources |
hitlChannels |
Human-in-the-loop delivery channels |
storage |
Session history and memory backends |
agentDeployers |
Deploy user agents to remote platforms |
Harness transports
Extension harnesses wire through three transports:
| Transport | Go client |
|---|---|
stdio (default) |
stdioHarnessAgent |
tcp |
ExtensionAgent (JSON-RPC 2.0) |
http |
HTTPExtensionAgent |
ADL agents reference extension harnesses as harness.type: ext:<extension>/<harness-id>.
Get started
- Getting started with extensions — install corp-pack and run your first extension agent
- Manifest reference — complete
extension.yamlschema - Programmatic SDK — Python, TypeScript, and Go packages
Examples in the repository
| Example | Demonstrates |
|---|---|
| corp-pack | Harnesses, MCP tools, skills, rules, mentions |
| hitl-demo | HITL channels and REST bridge |
| storage-demo | Custom persistence |
| docker-deployer | Agent deployer |
| programmatic-echo | Python NuiExtension package |