Claude Code plugin

Install once from the nexus repo — every Claude Code session on this host picks up the plugin automatically.

The nexus Claude Code plugin registers a skill and an MCP server so a main agent working in any repo can discover nexus, configure egress policy, and delegate a unit of work into a microVM sandbox. It requires the nexus binary on PATH — see Install.

Install

claude plugin marketplace add IniZio/nexus
claude plugin install nexus@nexus

Verify the MCP server is connected from any repo:

claude mcp list
# plugin:nexus:nexus: nexus mcp - ✔ Connected

Uninstall

claude plugin uninstall nexus@nexus
claude plugin marketplace remove nexus

What the plugin provides

Skills

One skill, nexus:nexus, is available in every Claude Code session after install. It is a dispatcher: its routing table opens the reference that matches the question — sandbox lifecycle, named volumes, guest setup, running an agent in a sandbox, creating a PR from inside a sandbox, first-run onboarding (.nexus/config.yaml and .nexus/Containerfile), egress policy authoring, and delegating a unit of work into a worktree sandbox.

Three slash commands ship alongside it: /nexus:nexus-init, /nexus:nexus-delegate, and /nexus:nexus-doctor.

MCP server

The plugin's .mcp.json wires nexus mcp as a stdio transport. The same 13-tool surface described in AI agents is available without any manual claude mcp add call.

`.nexus/config.yaml` — per-repo egress configuration

Repos that already have a .nexus/config.yaml are pre-configured. A worktree sandbox reads the file from its own checkout — the same file nexus create --file builds from — so a change takes effect on the next worktree-sandbox create for that checkout; no push to the default branch is needed.

Repos without one can run /nexus:nexus-init to generate one. The minimum structure:

yaml

version: 1
egress:
  policy:
    - host: api.github.com
      paths:
        - "/repos/owner/repo"
        - "/repos/owner/repo/**"
    - host: github.com
      paths:
        - "/owner/repo/**"
        - "/owner/repo.git/**"
  secrets:
    - env: GH_TOKEN
      hosts: [github.com, api.github.com]

Keep policy paths scoped to the repo

Never write /** at the host root. A path-scoped allowlist is what keeps a compromised guest from reaching other repos or the GraphQL write channel with the same token. See Egress and perimeter.

Existing ad-hoc MCP registration

If you registered nexus's MCP server manually before the plugin existed — claude mcp add --transport stdio nexus -- nexus mcp or a direct ~/.claude.json entry — you now have two registrations with the same name: one from the plugin's .mcp.json (pointing at the installed binary) and one from the manual entry (pointing at whatever binary the manual command referenced). Remove the manual entry to avoid the ambiguity.

What's built

Surface	Built	Live-proven
Marketplace install (`claude plugin marketplace add IniZio/nexus`)	Yes	No
Plugin MCP server (`plugin:nexus:nexus`)	Yes	Yes
`nexus` dispatcher skill (onboard, egress, delegate references)	Yes	Yes
`/nexus:nexus-init`, `-delegate`, `-doctor` commands	Yes	Yes
`nexus plugin install` CLI verb	No	—

Claude Code plugin ​

Install ​

Uninstall ​

What the plugin provides ​

Skills ​

MCP server ​

.nexus/config.yaml — per-repo egress configuration ​

Existing ad-hoc MCP registration ​

What's built ​