Connecting ChatGPT to Mandatum

This guide covers connecting ChatGPT to your Mandatum legal research data via the MCP/Actions OAuth integration.

Audience: Users with a ChatGPT Plus, Pro, Team, Enterprise, or Edu account who want to use Mandatum from within ChatGPT.

Note: ChatGPT Free accounts do not support this integration. The MCP/Actions OAuth connector requires a paid ChatGPT plan.

Important prerequisite: Developer Mode beta #

As of 2026, ChatGPT's MCP server integration is available as a Developer Mode beta feature. To use it:

1. You must have a ChatGPT Plus, Pro, Team, Enterprise, or Edu account.
2. You must opt in to the beta. Go to Settings → Beta features in ChatGPT and enable Developer Mode (or the equivalent option shown for your account type).
3. If the beta is not available on your account yet, it may be rolling out gradually. Check the OpenAI changelog for updates.

Enterprise and Edu accounts: Your organization's ChatGPT administrator must enable the Developer Mode/Actions beta for your workspace before individual users can access it. Contact your ChatGPT administrator if the option is not visible.

What this does #

Once connected, you can ask ChatGPT questions about statutes and legislation in your Mandatum organization's corpus. ChatGPT will retrieve information from Mandatum when you ask relevant questions.

Step-by-step instructions #

1. Enable Developer Mode beta #

1. Go to chatgpt.com and sign in.
2. Click your profile icon → Settings.
3. Select Beta features (or Advanced settings depending on your account type).
4. Enable Developer Mode or the MCP Servers / Actions beta option.
5. Save and close Settings.

2. Add Mandatum as a custom action / MCP server #

1. In ChatGPT, navigate to Explore → My GPTs → Create a GPT (or go to an existing GPT you manage), OR navigate to Settings → Integrations → Add MCP server if that option is available in your beta.
2. Look for Add action or Connect MCP server.
3. Enter your Mandatum discovery URL:
   Copy

   https://mandatum.intergentech.ai/.well-known/oauth-protected-resource

   (Replace mandatum.intergentech.ai with your organization's Mandatum URL if different.)
4. ChatGPT will fetch the metadata and recognize Mandatum as an OAuth-protected MCP server.

3. Configure OAuth #

1. When prompted for OAuth configuration, ChatGPT will need:
   • Authorization URL: https://mandatum.intergentech.ai/api/oauth/authorize
   • Token URL: https://mandatum.intergentech.ai/api/oauth/token
   • Client ID: Leave blank or enter a client ID obtained by calling the Mandatum DCR endpoint (see below).
   • Scope: the scopes you want ChatGPT to use, space-separated. searchStatutes getSection covers search and lookup. Add citation:verify for citation checks.
2. ChatGPT supports PKCE (which Mandatum requires). Ensure PKCE is enabled if prompted.

Optional: Pre-register a client via DCR #

For Teams/Enterprise environments, you may pre-register a ChatGPT client:

curl -X POST https://mandatum.intergentech.ai/api/oauth/register \
  -H "Content-Type: application/json" \
  -d '{
    "client_name": "ChatGPT-MyOrg",
    "redirect_uris": ["https://chatgpt.com/aip/plugin-oauth/token/approve"],
    "grant_types": ["authorization_code"]
  }'

Use the returned client_id in the ChatGPT OAuth configuration.

4. Authorize the connection #

1. ChatGPT will redirect you to Mandatum to authorize access.
2. Sign in to Mandatum if prompted.
3. Review the requested scopes and click Grant access.
4. You will be redirected back to ChatGPT.

5. Test the connection #

In a ChatGPT conversation, try:

• "Search Mandatum for environmental legislation"
• "What does Mandatum say about section 12 of the Planning Act?"

Revoking access #

To disconnect ChatGPT from Mandatum:

In ChatGPT: Go to the GPT/Actions settings and remove the Mandatum action.

In Mandatum: on the workspace's API keys page, find the ChatGPT connection under Connected apps and click Revoke.

Revocation is immediate.

Troubleshooting #

"Developer Mode not available": Your account plan or your organization's admin has not enabled the beta. Contact your ChatGPT administrator.

"OAuth error" during authorization: Ensure your ChatGPT redirect URI exactly matches one of:

• https://chatgpt.com/aip/plugin-oauth/token/approve
• https://chat.openai.com/aip/plugin-oauth/token/approve

Other redirect URIs are not accepted.

"Free plan" error: This integration requires a paid ChatGPT plan. Upgrade to Plus or higher.