ChatGPT Setup

Use this guide when ChatGPT should call Roster tools through a custom MCP app. ChatGPT currently describes these integrations as apps; older product and support pages may call them custom connectors.

Customer admins can share this page with end users after Roster is deployed. Replace <your-roster-public-url>/mcp with the customer’s Roster MCP URL.

Prerequisites

• A public HTTPS Roster MCP endpoint, for example <your-roster-public-url>/mcp.
• The default MCP auth mode allows user-based ChatGPT access plus API-key automation. Set ROSTER_MCP_AUTH_MODE=oauth only when ChatGPT/user access is the only MCP path.
• ROSTER_AUTH_URL set to the public Roster origin, for example <your-roster-public-url>.
• A ChatGPT plan or workspace that supports custom MCP apps.
• Roster identities mapped to the users who will authorize the app.
• An OAuth client-registration plan that follows MCP Authentication.

ChatGPT connects to the deployed Roster MCP endpoint over HTTPS.

Configure Roster

Set the MCP endpoint to allow OAuth clients. The default api_key,oauth also keeps API-key automation available:

ROSTER_AUTH_URL=<your-roster-public-url>

For an OAuth-only deployment:

ROSTER_MCP_AUTH_MODE=oauth

Roster derives the MCP OAuth resource URI automatically as ${ROSTER_AUTH_URL}/mcp.

ChatGPT should receive Roster-issued MCP OAuth tokens. Do not pass external IdP tokens, such as Entra ID or Okta tokens, directly to the MCP endpoint.

If the ChatGPT app setup requires self-registration, use the controlled registration window in MCP Authentication and close it after the app is registered.

Create The ChatGPT App

Use the ChatGPT workspace app setup flow to create or approve a Roster MCP app with these values:

Name : Roster

MCP server URL : <your-roster-public-url>/mcp

Authentication : OAuth

Purpose : Participant resolution and Roster management tools

Authorize the app through the Roster OAuth flow. The authorized user receives only the mcp:* scopes approved for that grant and identity.

After Roster is connected on ChatGPT web, the same connection is available to that user in the ChatGPT macOS app. Users do not need to repeat the MCP URL setup in the macOS app.

Use the workspace-approved distribution path when users should not create the app manually.

End-User Connection Values

For manual or self-service setup, customer admins can provide these values to end users:

Roster MCP URL:
<your-roster-public-url>/mcp

Connector name:
Roster

Description:
Use Roster to resolve approval routing, participants, delegations, labels, projects, and latest Resolve requests.

Required auth:
Sign in with your company account.

Tool Access

For read-only routing, grant:

mcp:resolve
mcp:resolve-requests:read
mcp:projects:read
mcp:participants:read

For project-maintenance workflows, add only the write scopes required by the use case:

mcp:projects:write
mcp:participants:write
mcp:labels:write
mcp:delegations:write

Write scopes do not bypass Roster authorization. A project owner can still only modify owned project data.

Roster advertises MCP safety annotations for ChatGPT and other clients. Read tools are marked read-only and non-destructive. Create/update/add tools are marked write and non-destructive. Delete/remove/revoke tools are marked destructive. After changing server tool metadata, reconnect the ChatGPT app so ChatGPT rediscovers the current tool descriptors and OAuth permissions.

Usage Prompts

For the most reliable first call in a conversation, mention Roster explicitly with @Roster or add Roster from the tools/app picker. ChatGPT may continue to use the Roster result naturally in follow-up questions in the same conversation, but end-user guidance should not promise automatic discovery for every new prompt.

First prompt:

@Roster resolve who should handle vendor security review for Atlas Operations.

Natural follow-up prompts can omit @Roster after the first Roster-backed answer:

Why those participants?

Show the latest Resolve request with project, requester, question, answer, selected participants, and identified users.

Use @Roster again when starting a new Roster-backed task or when ChatGPT does not select Roster automatically:

@Roster list the participants in the Atlas Operations project and show any active delegations.

For company knowledge or deep research scenarios, ChatGPT may limit custom apps to read-only data access. Roster’s MCP server is a full action-oriented MCP app with exact Roster tools, so use this setup for the platform workflows described here.

Publish

Before publishing the app to a workspace:

• Review the exposed Roster tools and disable write tools that are not needed.
• Verify OAuth consent text, callback behavior, and refresh-token behavior before enabling broad access.
• Confirm action approval settings for write tools such as project, participant, label, and delegation mutations.
• Grant workspace access only to groups that should use Roster.