$ mentions, such as $summation-start, or let Codex pick them up automatically when your request matches. Where a shell is available, the skills prefer sumcli for data work and fall back to the hosted MCP server.
Installing for Codex CLI
1
Add the Summation marketplace
2
Install the plugin
From the Start a new Codex thread (or restart Codex) so the plugin’s skills and MCP server load.
/plugins menu inside Codex, or the command line:3
Sign in
Sign me in to Summation. Codex picks the same skill automatically.The plugin ships a pre-wired connection to the hosted Summation MCP server. Codex opens a browser window to approve it using standard OAuth; codex mcp login summation does the same thing directly. Approve, pick your organization, and you’re connected. No codes to copy, no tokens to paste.4
Take the tour
Set up Summation and show me what data I can use. Codex starts the same guided flow.A guided first run: a map of your connected data, an introduction to the analyst, and your first report.Commands
You don’t need commands for most work. Describe what you need in plain English and the analyst picks it up.
The CLI underneath
Where Codex has a shell, the skills prefer sumcli for data operations, because the CLI exposes the full API contract, including operations the curated MCP toolset deliberately withholds: deletes, connection management, and ingestion batches. The skills check the installed version before the first CLI call and only install after you say yes. Session-start checks and routing hints are Claude Code-only today; on Codex the skills carry the routing. The CLI keeps its own sign-in, separate from the MCP browser approval:Installing for the Codex app
The Codex app adds a plugin marketplace through a dialog rather than the command line. The steps are the same underneath: add the marketplace, install the plugin, sign in.1
Open Add plugin marketplace
In the Codex app, open the plugins area and choose Add plugin marketplace.
2
Point it at the Summation repository
Fill in the dialog:
Then choose Add marketplace.If you must sparse-checkout, include both the catalog and the package:
.agents/plugins and plugins/summation. The package path alone fails with “marketplace root does not contain a supported manifest”.3
Install Summation
Open the Summation marketplace and install summation.
4
Sign in
Start a new thread and type
$summation-start (or $summation-signin), or ask in plain English: Set up Summation and show me what data I can use. Approve the connection in your browser, and the analyst connects and shows a map of your data.Troubleshooting
Summation tools return 401 / ask me to authenticate
Summation tools return 401 / ask me to authenticate
The MCP session expired or was never approved. Run
$summation-signin, or codex mcp login summation. It takes seconds in the browser.The Summation tools don't appear after installing
The Summation tools don't appear after installing
Codex loads plugins and MCP tools when a thread starts. Start a new Codex thread, or restart Codex, after installing.
The CLI says I'm not signed in even though Codex is connected
The CLI says I'm not signed in even though Codex is connected
The MCP browser approval and the CLI session are separate credentials, so run
sumcli auth login once. Being signed in over MCP doesn’t sign in the CLI, and vice versa.A report or query is taking a while
A report or query is taking a while
Report generation and validation are thorough and can take a minute or two. The analyst tells you it’s working. This is normal, not a hang.
I need automation or a non-production environment
I need automation or a non-production environment
The plugin is production and browser-approval only, the right default for almost everyone. For scripting and machine-to-machine access, use sumcli with an M2M profile or the Public API, or contact your Summation representative.