Connect Fine Structure to Mistral Le Chat

Le Chat has one of the cleanest custom connector forms of any chat product: a name, a URL, and Connect. It detects your server's authentication method automatically, so OAuth 2.1 with dynamic client registration just works and there is nothing to paste. The one thing to know is that adding connectors is an administrator action.

Before you start

• A Fine Structure account on the free tier or above.
• A Le Chat account. Mistral documents adding custom MCP connectors as an administrator only feature, and notes that on Free, Pro and Student plans the account owner is the administrator by default.
• On a team, an administrator has to create the connector before other members can use it.
• A connector name with no spaces or special characters, because Mistral treats it as a unique identifier.

Step by step

1. Open the Connectors page in Le Chat.
2. Click + Add Connector.
3. Switch to the Custom MCP Connector tab.
4. In Connector name, enter finestructure. Mistral requires a unique identifier with no spaces or special characters, so do not use a display name with a space in it.
5. In Server URL, enter https://finestructure.ai/api/mcp
6. Optionally add a description such as: builds, edits and publishes web apps.
7. Click Connect. Mistral detects the authentication method automatically and runs the OAuth 2.1 consent flow, which sends you to a Fine Structure sign in page.
8. Approve the consent screen, then ask Le Chat to list your Fine Structure apps to confirm the tools arrived.

What to watch out for

• Mistral documents OAuth 2.1 with dynamic client registration as one of the authentication methods it detects, which is exactly what Fine Structure serves, so this is a no credential setup.
• Mistral's docs state that custom connectors do not yet support dynamic tool discovery, resources or automatic prompt templates. In practice that means if the Fine Structure tool list changes later, you may need to reconnect the connector to pick up the change.
• Streamable HTTP is the transport Mistral's docs describe as the current standard, and it is what the Fine Structure endpoint speaks.
• Mistral is explicit that MCP connectors are not Mistral products and that you should connect only to servers you trust. That warning applies to every custom connector, not only this one.
• Compared with ChatGPT, there is no developer mode to unlock, and compared with Grok there is no separate admin console: the same page you use is the page an administrator uses.

Questions people ask

Do I need a paid Le Chat plan?

Mistral documents custom MCP connectors as an administrator only feature and notes that on Free, Pro and Student plans the account owner is the administrator by default, so an individual account owner on a free plan is the administrator of their own workspace.

Why does the connector name reject spaces?

Mistral uses the connector name as a unique identifier rather than a label, and its docs require no spaces or special characters. Use finestructure and put the human readable wording in the description field.

New Fine Structure tools are not showing up. What do I do?

Remove and re add the connector. Mistral's docs say custom connectors do not yet support dynamic tool discovery, so a tool list that changed on the server side may need a reconnect on the Le Chat side.

Vendor documentation we checked

• https://docs.mistral.ai/le-chat/knowledge-integrations/connectors/mcp-connectors
• https://finestructure.ai/api/mcp/docs

All platforms: connect Fine Structure to any AI. Also the documentation and pricing.