One — Claude Code MCP server: what it does, how to install
One gives AI agents a single MCP connection to connected apps, letting them find documented API actions and run them when a task needs it.
claude mcp add --transport http mcp https://mcp.withone.ai/mcpWhat One does
One connects an agent to actions in Gmail, Slack, Shopify, HubSpot, Stripe, Linear, QuickBooks, and other apps. It can identify the operations a task needs, return their documentation, and call an action on a connected platform. The server exposes three tools: list_one_integrations, find_one_actions, and execute_one_action.
Access can be scoped by connection, action, and permission level: read, write, or admin. Requests are proxied through One, with secrets redacted automatically. You can use the remote endpoint at https://mcp.withone.ai/mcp with OAuth, or run the local @withone/mcp package. The local setup through one init asks for an API key.
What it helps with
- find the API action needed for a task
- inspect action documentation before execution
- send a Slack message from an agent
- retrieve data from Gmail, Shopify, or Linear
- limit agent access by permission level
Example prompts for the agent
- Find and run the action that sends a message to a Slack channel.
- Fetch my latest Gmail messages and show their senders and subjects.
- Build a searchable, sortable table of QuickBooks invoices.
How to install One
1Platform CLI: remote server
claude mcp add --transport http mcp https://mcp.withone.ai/mcp2Platform CLI
claude mcp add --env ONE_SECRET=<ONE_SECRET> --env ONE_PERMISSIONS=<ONE_PERMISSIONS> --env ONE_CONNECTION_KEYS=<ONE_CONNECTION_KEYS> --env ONE_ACTION_IDS=<ONE_ACTION_IDS> --env ONE_KNOWLEDGE_AGENT=<ONE_KNOWLEDGE_AGENT> --transport stdio one -- npx -y @withone/mcpReplace <…> with your own values. 2 more environment variables are in the server README
1Platform CLI: remote server
codex mcp add one --url https://mcp.withone.ai/mcp2Platform CLI
codex mcp add one --env ONE_SECRET=<ONE_SECRET> --env ONE_PERMISSIONS=<ONE_PERMISSIONS> --env ONE_CONNECTION_KEYS=<ONE_CONNECTION_KEYS> --env ONE_ACTION_IDS=<ONE_ACTION_IDS> --env ONE_KNOWLEDGE_AGENT=<ONE_KNOWLEDGE_AGENT> -- npx -y @withone/mcpReplace <…> with your own values. 2 more environment variables are in the server README
Config file
{
"mcpServers": {
"one": {
"url": "https://mcp.withone.ai/mcp"
}
}
}{
"mcpServers": {
"one": {
"command": "npx",
"args": [
"-y",
"@withone/mcp"
],
"env": {
"ONE_SECRET": "<ONE_SECRET>",
"ONE_PERMISSIONS": "<ONE_PERMISSIONS>",
"ONE_CONNECTION_KEYS": "<ONE_CONNECTION_KEYS>",
"ONE_ACTION_IDS": "<ONE_ACTION_IDS>",
"ONE_KNOWLEDGE_AGENT": "<ONE_KNOWLEDGE_AGENT>"
}
}
}
}Replace <…> with your own values. 2 more environment variables are in the server README
Config file
{
"servers": {
"one": {
"type": "http",
"url": "https://mcp.withone.ai/mcp"
}
}
}{
"servers": {
"one": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@withone/mcp"
],
"env": {
"ONE_SECRET": "<ONE_SECRET>",
"ONE_PERMISSIONS": "<ONE_PERMISSIONS>",
"ONE_CONNECTION_KEYS": "<ONE_CONNECTION_KEYS>",
"ONE_ACTION_IDS": "<ONE_ACTION_IDS>",
"ONE_KNOWLEDGE_AGENT": "<ONE_KNOWLEDGE_AGENT>"
}
}
}
}Replace <…> with your own values. 2 more environment variables are in the server README
1Platform CLI: remote server
gemini mcp add -t http one https://mcp.withone.ai/mcp2Platform CLI
gemini mcp add -e ONE_SECRET=<ONE_SECRET> -e ONE_PERMISSIONS=<ONE_PERMISSIONS> -e ONE_CONNECTION_KEYS=<ONE_CONNECTION_KEYS> -e ONE_ACTION_IDS=<ONE_ACTION_IDS> -e ONE_KNOWLEDGE_AGENT=<ONE_KNOWLEDGE_AGENT> one npx -y @withone/mcpReplace <…> with your own values. 2 more environment variables are in the server README
Step by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about One
How do I install One in Claude Code?
Run claude mcp add --transport http one https://mcp.withone.ai/mcp. Claude Code then opens One’s OAuth authorization flow on the first connection.
What does One do?
One finds the app action a task requires, provides its documentation, and executes the API call through three MCP tools.
How does the remote setup differ from the local one?
The remote server uses https://mcp.withone.ai/mcp and OAuth, so it does not need npm install or ONE_SECRET. The local option runs @withone/mcp and uses API-related environment settings.
