Connect to Hardline MCP

Use this guide to connect an MCP-compatible client to Hardline production.

MCP server URL

https://api.hardlineapp.com/mcp

Use your production Hardline login when the OAuth browser flow opens.

If you previously configured a development MCP URL, remove or update it first. Production clients should not use https://test-api.hardlineapp.com/mcp or https://newapp.hardlineapp.com/mcp.

Codex

CLI:

codex mcp add hardline --url https://api.hardlineapp.com/mcp
codex mcp list

Or edit ~/.codex/config.toml:

[mcp_servers.hardline]
url = "https://api.hardlineapp.com/mcp"

Restart Codex after editing the config file.

Claude Code

claude mcp add --transport http hardline https://api.hardlineapp.com/mcp

Then run /mcp inside Claude Code and complete the browser OAuth flow.

Claude, Claude Desktop, and claude.ai

Claude remote custom connectors use Anthropic’s cloud connector flow.

• Pro or Max: go to Customize > Connectors > + > Add custom connector
• Team or Enterprise: an Owner should add it under Organization settings > Connectors > Add > Custom > Web

Use this URL:

https://api.hardlineapp.com/mcp

Then click Connect and authenticate with your Hardline production account.

ChatGPT

ChatGPT connects to remote MCP servers through custom apps. Availability and exact labels can vary by plan, but the production Hardline MCP URL is the same:

https://api.hardlineapp.com/mcp

Individual setup

Use this path when you are setting up Hardline MCP for your own ChatGPT account or testing it before a workspace rollout.

1. Open ChatGPT on the web.
2. Go to Settings > Apps > Advanced settings.
3. Turn on Developer mode.
4. Go back to Settings > Apps.
5. Click Create app. If you do not see this button, confirm developer mode is enabled and that your plan or workspace allows custom apps.
6. Name the app Hardline.
7. Enter the MCP server URL:

https://api.hardlineapp.com/mcp

8. Choose OAuth if ChatGPT asks for an authentication method.
9. Scan or refresh tools when prompted.
10. Complete the Hardline OAuth browser flow with your production Hardline account.
11. Open a new ChatGPT conversation, click +, choose More, and select the Hardline app from the available tools.

Try a prompt such as:

Use Hardline to find my recent call summaries.

ChatGPT Business admin setup

Use this path when a ChatGPT Business workspace admin or owner wants to make Hardline available to the workspace.

1. In ChatGPT, open Workspace settings.
2. Go to Permissions & Roles > Connected Data.
3. Enable Developer mode / Create custom MCP connectors for your own admin account.
4. Go to Workspace settings > Apps > Create.
5. Create a new app named Hardline.
6. Use the MCP server URL:

https://api.hardlineapp.com/mcp

7. Choose OAuth when asked for authentication.
8. Scan tools, complete the Hardline OAuth flow, and create the draft app.
9. Review the app under Workspace settings > Apps > Drafts.
10. Publish the app when you are ready for workspace users to connect it.
11. After publishing, review Action control for the app and decide whether to allow all actions, read-only actions, or a custom set of actions.

Business workspace admins and owners can create and publish custom apps. Regular workspace members cannot create custom MCP apps themselves; they connect to apps that an admin has enabled.

ChatGPT Enterprise admin setup

Use this path when an Enterprise admin wants tighter rollout control.

1. In ChatGPT, open Workspace settings.
2. Go to Permissions & Roles > Connected Data.
3. Use RBAC to grant developer mode access to the admins or developers who should create and test the app.
4. Each authorized creator should turn on developer mode from Settings > Apps > Advanced settings.
5. Create the Hardline app from Workspace settings > Apps > Create or from user Settings > Apps > Create.
6. Use the MCP server URL:

https://api.hardlineapp.com/mcp

7. Choose OAuth when asked for authentication.
8. Scan tools, complete the Hardline OAuth flow, and create the draft app.
9. Review the app under Workspace settings > Apps > Drafts.
10. Publish the app for the workspace.
11. Configure user access with RBAC so only the intended people or groups can connect Hardline.
12. Open Action control for the published app and review the available actions. If Hardline later adds or changes tools, refresh actions and review the diff before enabling new actions.

Enterprise workspaces usually keep apps disabled until an admin enables and publishes them. End users still authenticate with their own Hardline account before first use.

ChatGPT notes

• ChatGPT custom MCP apps are available on ChatGPT web. Configure and test from the web app first.
• The Hardline MCP app is not an OpenAI-verified public app directory listing. Add it only if your organization trusts Hardline as a connected service.
• If ChatGPT cannot scan tools, confirm the URL is exactly https://api.hardlineapp.com/mcp, then try refreshing the app or recreating it.
• If users can see the app but cannot connect it, check workspace app availability, RBAC/user access, and action controls.

Available access

The MCP authorization screen will show the permissions requested by the client. Depending on the client and enabled scopes, Hardline MCP can expose:

• Search and retrieval of Hardline context
• Call summaries and related project documentation
• Artifact media when explicitly authorized
• Miriel query or learning capabilities when enabled for your account

Only approve clients you trust.

Troubleshooting

If you see:

Invalid Host header

or:

Unexpected content type: missing-content-type; body: Invalid Host header

check that the client is using the production URL exactly:

https://api.hardlineapp.com/mcp

If the URL is correct, remove the MCP server from the client, restart the client, and add it again. If the issue persists, contact support@hardlineapp.com with the client name, timestamp, and the exact error text.