MCP server

ChatGPT

1. 1Go to Plugins (chatgpt.com/plugins), click + and pick Add custom MCP server.
2. 2Name it ApresMail, enter http://localhost:3000/mcp as the server URL and pick OAuth, with no client ID or secret. If ChatGPT asks how to register, pick Client ID Metadata Document.
3. 3Check I understand and want to continue, then click Create as a plugin.
4. 4Install the plugin, sign in to ApresMail when ChatGPT asks, choose permissions and click Allow.
5. 5In a chat, type @ and pick ApresMail.

Custom MCP servers are on ChatGPT on the web, for Business, Enterprise and Edu workspaces: on Business, admins and owners add them; on Enterprise and Edu, so can the members an admin allows. On Pro, ChatGPT only uses the read-only tools for now.

Claude

1. 1Go to Customize › Connectors and click Add custom connector.
2. 2Name it ApresMail and enter http://localhost:3000/mcp. If Claude asks how it identifies itself, keep Use Claude's published identity. Click Add.
3. 3Click Connect, sign in to ApresMail, choose permissions and click Allow.
4. 4The connector works in claude.ai, Claude Desktop and the mobile apps. Turn it on or off in a chat from + › Connectors.

On Team and Enterprise plans, an owner adds it once in Organization settings › Connectors › Add › Custom › Web, then each member clicks Connect under Customize › Connectors. The Free plan has one custom connector.

Grok Bot

1. 1In a chat, ask Grok Bot to add the custom MCP server http://localhost:3000/mcp.
2. 2Sign in to ApresMail when it asks, choose permissions and click Allow.

Claude Code

claude mcp add --transport http --scope user apresmail http://localhost:3000/mcp \
  --header "Authorization: Bearer $APRESMAIL_API_KEY"

The shell puts the key in Claude Code's settings when the command runs. --scope user makes the server available in every project; run /mcp in Claude Code to check it's connected.

Codex

[mcp_servers.apresmail]
url = "http://localhost:3000/mcp"
bearer_token_env_var = "APRESMAIL_API_KEY"

Codex reads the key from APRESMAIL_API_KEY each time it starts, so export it in your shell profile. The same server from the terminal: codex mcp add apresmail --url http://localhost:3000/mcp --bearer-token-env-var APRESMAIL_API_KEY

Cursor

{
  "mcpServers": {
    "apresmail": {
      "url": "http://localhost:3000/mcp",
      "headers": {
        "Authorization": "Bearer ${env:APRESMAIL_API_KEY}"
      }
    }
  }
}

Cursor reads APRESMAIL_API_KEY from the environment it was opened in. If it isn't set there, put the key itself after Bearer, and keep the file out of version control.

Connected apps

An app gets only the permissions you select, in your account only. Sending and subscriber data are separate. Older full grants stay labeled legacy until you revoke or replace them. The API keys page lists connected apps with when they were last used. Revoke one there and its tokens stop working right away; it has to ask you again to come back.