Eulerian MCP Integration Guide for Antigravity
EULERIAN MCP
- Google Antigravity integration guide
- For users without advanced technical knowledge
- Remote connector with OAuth 2.1 · Desktop app · mcp_config.json
1. What it is and how it differs from the other versions
This guide connects Google Antigravity to Eulerian's remote MCP server. Antigravity is Google's desktop application (an agentic IDE); it supports remote MCP servers with OAuth 2.1 authentication. You install no local server and paste no API token: the connector is added in the mcp_config.json file and you sign in with your own Eulerian account. The main difference versus Claude, ChatGPT or Mistral is that here the connector is set up from a configuration file and the OAuth sign-in includes a copy-and-paste code step.
The principle, in one sentenceA remote endpoint + OAuth sign-in: you install no local servers, store no API tokens, and Antigravity 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 exporting data manually.
2. Before you begin
You need these four items before continuing:
1
The Antigravity app
Download and install Antigravity for your system (Windows, macOS or Linux) from antigravity.google/download . This guide uses Antigravity 2.0 (desktop app).
2
A Google account
Antigravity starts with “Continue with Google”, so you need a Google account to use the application.
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: in the desktop app, 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 Download and install Antigravity
Go to antigravity.google/download and download Antigravity for your system (Windows, macOS or Linux). Install it like any desktop application. This guide uses Antigravity 2.0.
The official Google Antigravity download page, with builds for macOS, Windows and Linux.
Step 2 Open it and sign in with Google
The first time you open Antigravity, click Continue with Google and follow the welcome wizard until you reach the main window, where you have New Conversation and, bottom-left, Settings.
Welcome screen: sign in with “Continue with Google”.
Antigravity's main window, with “New Conversation” and “Settings” at the bottom-left.
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 tokenUnlike other methods, here 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 settings in Antigravity
In Antigravity, open Settings (bottom-left) and go to Customizations. In the Installed MCP Servers block you'll see the Add MCP, Refresh and Open MCP Config buttons.
Settings → Customizations: the “Installed MCP Servers” block with “Open MCP Config”.
Step 5 Add Eulerian's server in mcp_config.json
Click Open MCP Config to open the mcp_config.json file. Add Eulerian's server with your endpoint and /mcp at the end, then save the file:
{"mcpServers": {"eulerian": {"serverUrl": "https://<your-Eulerian-API-endpoint>/mcp"}}}
mcp_config.json with the “eulerian” server and its serverUrl ending in /mcp (demo endpoint).
Step 6 Click Refresh, then Authenticate
Go back to Customizations and click Refresh. The Eulerian server will appear with an Authenticate button. Click it to start the OAuth sign-in.
After “Refresh”, the “Eulerian” connector shows the “Authenticate” button.
Error state: if you see “initialize: Unauthorized” with no “Authenticate” button, see Section 7.
If the “Authenticate” button doesn't appearIf instead you see “Error: initialize Unauthorized”, the MCP server isn't advertising OAuth correctly. Wait a few seconds and click “Refresh” again; if it persists, contact Eulerian (see Section 7).
Step 7 Sign in to Eulerian
Eulerian's sign-in screen opens in your browser. Enter your username (Identifiant) and continue with your Eulerian password. Antigravity never sees your password.
Eulerian's sign-in screen.
Step 8 Authorize access (Approve)
Eulerian shows the permissions antigravity-client requests (for example eulerian:reports.read). Review them and click “Approve” to authorize (or “Deny” to cancel).
Eulerian's authorization screen: review the permissions and click “Approve”.
Grant only what's neededAlways review the permissions before approving. For read-only reports, eulerian:reports.read is enough; grant write permissions only if your use case requires it.
Step 9 Copy the code and paste it into Antigravity
After approving, Antigravity shows a one-time code. Click Copy to Clipboard, go back to Antigravity and paste the code into the “Paste auth code” field; then click Submit.
Antigravity shows a one-time code: copy it with “Copy to Clipboard” (code hidden).
In Antigravity, paste the code into “Paste auth code” and click “Submit”.
Step 10 Connector connected
The Eulerian connector turns green with a Sign out button and shows the number of enabled tools (for example “133 tools enabled”). It's now connected.
The “Eulerian” connector connected (green dot, “Sign out”) with its tools enabled.
Connection completeNo local servers installed and no API tokens stored. You can revoke access at any time with “Sign out” in Antigravity or from your Eulerian account.
Step 11 Use it
Open a new conversation and ask in natural language. Antigravity will call Eulerian's tools based on what you ask, for example:
Which Eulerian tools do you have access to, and what websites are in my account?
Antigravity replies using Eulerian's MCP, listing the available tools.
4. Teams and organisations
Antigravity stores the MCP configuration 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 local mcp_config.json; you can have several MCP servers at once.
- 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: you can disconnect it with “Sign out” in Antigravity or revoke it from your Eulerian account at any time.
5. Other clients and notes
Because authentication uses OAuth 2.1 and is delegated to the MCP client, the same Eulerian remote endpoint works with other MCP-compatible clients (Claude, ChatGPT, Mistral, etc.). Eulerian's part — endpoint URL, OAuth sign-in and authorization — is always the same; only where each platform adds the connector changes.
Desktop app versus Antigravity CLIThis guide covers the desktop app (Antigravity 2.0), configured from Settings → Customizations with OAuth. Antigravity also offers a CLI and an IDE; how you add the MCP server may vary, 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: Claude (web and desktop), 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 Antigravity a limited access (for example, read-only reports) that is revocable at any time.
The authorization code is one-time
The code you copy and paste during sign-in 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”. Grant only what's needed and 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.
Validate with your IT department
Before using real business data, confirm with IT which AI platforms are approved for processing company data.
7. If something doesn't work
The connector shows “initialize: Unauthorized” and no “Authenticate” appears
The MCP server isn't advertising OAuth correctly. Click “Refresh” again after a few seconds; if it persists, contact Eulerian to review the endpoint's OAuth discovery.
I can't find where to add the connector
In Settings → Customizations, “Installed MCP Servers” block, use “Open MCP Config” to edit mcp_config.json.
The connection won't establish or is flagged invalid
Check the URL: it must be your Eulerian API endpoint with /mcp appended, over HTTPS and with a valid TLS certificate.
The connection doesn't reach the server
The endpoint must be reachable from your computer over the internet. If it's behind a corporate firewall or VPN, it may not connect.
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 still won't connect
Copy the full code with “Copy to Clipboard” and paste it into “Paste auth code” before it expires; if it expires, start again from “Authenticate”.
The assistant says it has no access to the MCP
Check the connector is green (“Sign out”) and enabled (toggle). Open a new conversation and ask 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
- Eulerian OAuth 2.1 (third-party integrations): doc.api.eulerian.com/#section/Introduction/OAuth-2.1-for-third-party-integrations
- Antigravity download: antigravity.google/download
- GitHub repository: github.com/EulerianTechnologies/eulerian-marketing-platform-mcp