Eulerian MCP Integration Guide for Antigravity CLI
EULERIAN MCP
- Antigravity CLI integration guide
- For users without advanced technical knowledge
- Remote connector with OAuth 2.1 · Terminal (agy) · mcp_config.json
1. What it is and how it differs from the other versions
This guide connects Antigravity CLI to Eulerian's remote MCP server. The CLI (the agy command) is Google's terminal version: an agent you work with by typing in the console, with no graphical interface. It supports remote MCP servers with OAuth 2.1 authentication. You paste no API token: the connector is added in the mcp_config.json file and you sign in with your own Eulerian account. Versus Antigravity 2.0 and the IDE, here everything happens in the terminal: you open the manager with the /mcp command and the OAuth sign-in is completed by pasting a code into the console itself.
The principle, in one sentenceA remote endpoint + OAuth sign-in: you store no API tokens and the CLI never sees your password. Eulerian grants only a limited, revocable access.
What you can do with it:
- Check last week's paid search campaign performance with a single sentence.
- Find out which media channels drove the most conversions this month.
- Analyse the customer journey of your highest-converting segment.
- Get analytics insights without leaving the terminal.
2. Before you begin
You need these four items before continuing:
1
The Antigravity CLI (agy)
Installed with a single command (see Step 1). Works on Windows, macOS and Linux. It shares account and configuration with Antigravity 2.0 and the IDE.
2
A Google account
The CLI signs in with your Google account the first time you launch it (or reuses the existing session if you use Antigravity 2.0/IDE).
3
Eulerian's MCP endpoint URL
It's your Eulerian API endpoint with /mcp appended. You find it in the Eulerian interface, within your account, under the "Eulerian API" section.
4
Your Eulerian credentials
Your Eulerian username and password. You'll sign in during the OAuth step. There is no API token to paste.
Endpoint requirementsThe endpoint must be reachable over the internet and over HTTPS with a valid TLS certificate: the connection originates from your computer. If you have access to several grids, use the endpoint of the relevant one.
3. Step-by-step setup
Step 1 Install the CLI (agy)
Open a terminal and run the installer for your system. On Windows, open PowerShell (Windows key → type "powershell" → Enter) and paste:
Other platformsWindows (CMD): curl -fsSL https://antigravity.google/cli/install.cmd -o install.cmd && install.cmd && del install.cmd · macOS and Linux: curl -fsSL https://antigravity.google/cli/install.sh | bash. After installing, close and reopen the terminal so it recognises the agy command.
Step 2 Launch "agy" and finish the welcome
In a fresh terminal, type agy and press Enter. The first time, the CLI may open your browser to sign in with your Google account (or reuse the existing session). Then complete the wizard: choose a color theme (↑/↓ arrows + Enter), accept the terms of use ([Done]) and, when asked, trust the folder ("Yes, I trust this folder").
First launch of the CLI: choose a color theme with the arrows and press Enter.
The CLI asks you to trust the folder you open it from; leave "Yes, I trust this folder" and press Enter.
Sign-in on first runIt may ask you to sign in via the browser with your Google account, or reuse the existing session if you share credentials with Antigravity 2.0/IDE.
Step 3 Find your MCP endpoint in Eulerian
In the Eulerian interface, within your account, open the Eulerian API section. Your API Endpoint is shown there. The MCP server URL is that same endpoint with /mcp appended:
The "Eulerian API" section: your API Endpoint (demo values). You don't need the API token for this method.
https://<your-Eulerian-API-endpoint>/mcp
You don't need the API tokenHere you don't copy the API token. You only need the endpoint URL with /mcp; you'll identify yourself with your username and password during the OAuth step.
Step 4 Open the mcp_config.json configuration file
The connector is defined in a text file the CLI shares with Antigravity 2.0 and the IDE. Open it with a text editor. On Windows (in PowerShell):
notepad $env:USERPROFILE\.gemini\config\mcp_config.json
Where the file isWindows: C:\Users\<your-username>\.gemini\config\mcp_config.json · macOS and Linux: ~/.gemini/config/mcp_config.json. If the editor asks whether to create the file, say yes. You can also use it per project in .agents/mcp_config.json.
Step 5 Add Eulerian's server and save
Paste this content into the file (replace with your endpoint, with /mcp at the end) and save (File → Save):
{"mcpServers": {"eulerian": {"serverUrl": "https://<your-Eulerian-API-endpoint>/mcp"}}}
If you already added it in 2.0 or the IDESince the three surfaces share this file, Eulerian may already be there. In that case you don't need to add it again: skip straight to Step 6.
Step 6 Open the MCP manager with /mcp
In the CLI prompt box, type /mcp and press Enter. The MCP Servers manager opens, where you'll see Eulerian. Since you haven't signed in yet, it will show [Auth Needed] with an "Unauthorized" notice (this is normal; we fix it in the next step).
The "MCP Servers" manager shows Eulerian with "[Auth Needed]": authentication is missing.
Step 7 Start authentication
With Eulerian selected (the `>` arrow to its left), press Enter to open the actions. You'll see Restart, Disable and [Authenticate]. Move to Authenticate and press Enter.
With Eulerian selected, press Enter and choose "Authenticate".
Step 8 Sign in and authorize in the browser
The CLI opens your browser with Eulerian's sign-in page. Enter your Eulerian username and password, and on the permissions screen click "Approve" (the CLI never sees your password).
Eulerian's sign-in screen.
Authorization in Eulerian: review the permissions and click "Approve".
Grant only what's neededReview the permissions before approving. For read-only reports, eulerian:reports.read is enough; grant write only if your use case requires it.
Step 9 Copy the code and paste it into the terminal
The browser shows a one-time code (click Copy to Clipboard). Go back to the terminal: the CLI is waiting at "Paste the authorization code below". Paste the code and press Enter. You'll see "Authentication successful!".
Antigravity shows a one-time code: copy it with "Copy to Clipboard" (code hidden).
The CLI asks you to paste the authorization code (the URL is hidden); paste it and press Enter.
If the browser doesn't open automaticallyThe terminal prints an authorization URL: copy it and open it manually in the browser to sign in, then paste the code here.
Step 10 Connector connected
Press Enter to return to the MCP panel. Now Eulerian appears as ✓ [Authed] with the list of available tools. It's now connected.
Eulerian connected: "✓ Eulerian [Authed]" with its tools (eulerian_tool_invoke, …).
Connection completeNo tokens pasted. You can sign the CLI out at any time with the /logout command, or revoke access from your Eulerian account.
Step 11 Use it
Press Esc to leave the MCP panel and return to the prompt box. There, type your question in natural language and press Enter; the CLI will call Eulerian's tools. For example:
Which Eulerian tools do you have access to?
The CLI replies using Eulerian's MCP, listing the available tools.
4. Teams and organisations
The MCP configuration lives in the mcp_config.json file on your computer, and authentication is individual: each user signs in with their own Eulerian account.
- The connector is defined in your mcp_config.json (global at ~/.gemini/config/mcp_config.json or per project in .agents/mcp_config.json).
- Each user connects with their own Eulerian account, so they only access the data their account can see.
- In corporate environments, confirm with your IT department which AI tools are approved for processing business data.
The access granted is limited and revocable: use the /logout command in the CLI to sign out, or revoke it from your Eulerian account at any time.
5. Other clients and notes
Antigravity 2.0, the IDE and the CLI share the same MCP configuration file (~/.gemini/config/mcp_config.json) and the same session. If you already added Eulerian on another surface, the CLI detects it. And because authentication is OAuth 2.1 delegated to the client, the same endpoint also works with Claude, ChatGPT or Mistral: Eulerian's part is always the same; only where you add the connector changes.
CLI versus Antigravity 2.0 and IDEThis guide covers the terminal (Antigravity CLI, the agy command). Antigravity 2.0 is the agent app and the IDE is the code editor; each has its own guide, but Eulerian's part (endpoint + OAuth) is identical.
- Eulerian OAuth 2.1 (third-party integrations): doc.api.eulerian.com/#section/Introduction/OAuth-2.1-for-third-party-integrations
- Client-specific guides: Antigravity 2.0, Antigravity IDE, Claude, ChatGPT, Mistral and "Other clients".
6. Security and best practices
OAuth instead of tokens
No API token is stored on your computer. You authenticate with your Eulerian account and Eulerian grants the CLI a limited access (for example, read-only reports) that is revocable at any time.
The authorization code is one-time
The code you paste into the terminal is temporary and single-use: it only serves to complete authentication and expires quickly. It is not a token to store or share.
Explicit, minimal permissions
Review the permissions on Eulerian's authorization screen (for example eulerian:reports.read) before clicking "Approve". Avoid write permissions if you won't use them.
Trusted connectors only
Only add MCP servers from developers you trust. Always verify the origin of the URL: here, the developer is Eulerian.
Sign out when you're done
Use /logout to disconnect your account and clear the credentials saved on the computer. Before using real data, confirm with IT which AI platforms are approved.
7. If something doesn't work
"agy" is not recognised as a command
Close and reopen the terminal so it picks up the new PATH after installing. If it persists, reinstall with the Step 1 command.
I don't see Eulerian when I open /mcp
It hasn't been added to the config file: open it with a text editor (Step 4) and paste the block from Step 5, save and reopen /mcp.
Eulerian shows "[Auth Needed]" / "Unauthorized"
That's normal before signing in. Select Eulerian, press Enter and choose "Authenticate" (Step 7). If it persists after authenticating, contact Eulerian.
The browser doesn't open at the sign-in step
The terminal prints a URL: copy it and open it manually in the browser. After approving, copy the code and paste it into the terminal.
Eulerian rejects the sign-in
Use your Eulerian credentials (not your Google ones). If you have access to several grids, use the endpoint of the correct one.
I pasted the code but it won't connect
Copy the full code with "Copy to Clipboard" and paste it before it expires; if it expires, run "Authenticate" again.
I want to start the session from scratch
Run /logout in the CLI to clear the saved credentials and authenticate again.
8. Additional resources
- Your API endpoint: in the Eulerian interface, "Eulerian API" section (append /mcp).
- Eulerian MCP Server documentation: doc.eulerian.com/p/NhupKnGmQtUv_E/MCP-Server
- Antigravity CLI — installation and use (official docs): antigravity.google/docs/cli/install
- MCP in Antigravity CLI (official docs): antigravity.google/docs/cli/mcp
- Eulerian OAuth 2.1 (third-party integrations): doc.api.eulerian.com/#section/Introduction/OAuth-2.1-for-third-party-integrations
- GitHub repository: github.com/EulerianTechnologies/eulerian-marketing-platform-mcp