Engines and runtimeAgents
Grok Build
xAI's Grok Build agent inside Sentinel, on the shared ACP engine.
Sentinel can run a thread on Grok Build, xAI's coding agent CLI.
It starts grok agent stdio and talks to it over ACP, on the same engine that carries Cursor, Antigravity, and registry agents. Grok Build support is experimental.
Setup
| What | Details |
|---|---|
| Install | npm install -g @xai-official/grok, or curl -fsSL https://x.ai/cli/install.sh | bash |
| Update | grok update |
| Required | Grok 1.0.13 or newer; older builds predate the agent protocol Sentinel drives |
| Home variable | GROK_HOME |
Sign-in
- Sign in with Grok runs
grok loginin a terminal inside the Grok card; approve the sign-in in your browser. - Use an xAI API key stores the key encrypted on the instance as
XAI_API_KEY.
Running a thread
- Permission modes: Default, Auto, and Full. Grok has no accept-edits mode. The mode is a launch flag, so changing it restarts the Grok process.
- Plan mode: Sentinel's plan prompt. When Grok finishes its plan, it shows up as a plan card.
- Questions Grok asks become question cards.
- Background tasks and subagents get their own cards. Stopping a turn stops them with it.
- Models come from Grok, with the reasoning efforts each one offers.
- Images can be attached to a prompt, and MCP servers from Settings are passed to Grok.
Usage limits
The Grok card and the composer show the credit percentage of the grok.com login the CLI uses. Accounts set up any other way, such as an API key, are left alone: nothing is read or sent for them.
Skills and slash commands
Grok reports its slash commands, and the composer's slash menu offers them. Sentinel also reads Grok's skills with grok inspect --json, but skills for Grok are managed in Grok itself.