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Connect ChatGPT to ToolMesh

ChatGPT supports MCP servers, but only remote HTTPS servers and only through Developer Mode. This guide walks through connecting ChatGPT to your ToolMesh instance.

Requirements

Section titled “Requirements”
  • A Plus, Pro, Business, Enterprise, or Education plan (Free plan has no MCP support)
  • ToolMesh accessible via a public HTTPS URL (ChatGPT cannot connect to http:// or localhost)
  • For local development, use ngrok or Cloudflare Tunnel to expose your ToolMesh instance

Step-by-step setup

Section titled “Step-by-step setup”

1. Enable Developer Mode

Section titled “1. Enable Developer Mode”

Open Settings > Apps & Connectors > Advanced settings and toggle Developer Mode on.

Note: Developer Mode disables Memory for conversations that use MCP tools.

2. Create the ToolMesh connector

Section titled “2. Create the ToolMesh connector”

Return to the Apps & Connectors settings page. Click the Create button (only visible after enabling Developer Mode) and fill in:

FieldValue
NameToolMesh
DescriptionSecure execution layer for infrastructure tools
MCP Server URLhttps://toolmesh.example.com/mcp
AuthenticationOAuth or No Authentication

Check I trust this application and click Create. If the connection succeeds, ChatGPT displays a list of available ToolMesh tools.

3. Complete OAuth (if applicable)

Section titled “3. Complete OAuth (if applicable)”

If your ToolMesh instance uses OAuth, ChatGPT redirects to the login page. Authorize access, and you are returned to ChatGPT with the connector authenticated.

ChatGPT supports OAuth 2.1 with PKCE and dynamic client registration. It queries /.well-known/oauth-protected-resource on the ToolMesh server to discover the authorization server.

4. Enable ToolMesh in a conversation

Section titled “4. Enable ToolMesh in a conversation”

Open a new chat, click the + button near the message composer, select More > Developer Mode, then Add sources and enable ToolMesh.

The connector must be enabled in each new conversation — it does not carry over.

5. Use your tools

Section titled “5. Use your tools”

Prompt naturally (e.g. “List my open GitHub issues”, “Show server status”). ChatGPT shows expandable JSON payloads for each tool call. Write operations require manual confirmation before execution.

Transport and authentication details

Section titled “Transport and authentication details”

Supported transports: ChatGPT supports Streamable HTTP (recommended) and SSE. The runtime auto-detects the protocol. stdio is not supported — ChatGPT cannot launch local servers.

Authentication: The ChatGPT UI offers OAuth 2.1 or no authentication. Bearer token / API key authentication is not natively supported in the UI. If your ToolMesh instance uses API keys, you need to either:

  • Configure OAuth authentication on ToolMesh instead (recommended for ChatGPT)
  • Proxy through mcp-remote with a --header flag as a workaround

Plan availability

Section titled “Plan availability”
PlanDeveloper Mode (full MCP)
FreeNo
PlusYes (beta)
ProYes (beta)
TeamLimited
BusinessYes (beta)
EnterpriseYes (beta)
EducationYes (beta)

For Business, Enterprise, and Education plans, workspace admins must enable Developer Mode from Workspace Settings > Permissions & Roles before individual users can access it.

Known limitations

Section titled “Known limitations”
  • Per-chat activation — every new conversation requires manually enabling Developer Mode and selecting ToolMesh through the + > More > Developer Mode > Add sources flow. There is no “always on” setting.
  • Memory disabled — ChatGPT cannot learn preferences or recall past interactions when using MCP tools.
  • Tool count — servers exposing more than 30-40 tools can degrade model performance. ToolMesh lets you control which backends and tools are exposed per user via authorization policies.
  • HTTPS only — ChatGPT cannot connect to plain HTTP endpoints. For local development, use a tunneling service.

Next steps

Section titled “Next steps”