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Connect Writer

Add Stensul to Writer as a custom MCP connector with OAuth, a client secret and two redirect URIs.

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Writer doesn’t support PKCE, so the Stensul connection needs a client secret, and it needs two redirect URIs: Writer’s callback and your Stensul instance callback.

1. Create the API connection in Stensul

Needs admin access, the external API enabled and access_admin_api_connections.

  1. Go to Admin > Settings > API connections and click Add connection.
  2. Set Authorization Type to Authorization Code. Name it, for example mcp-writer.
  3. Add both redirect URIs:
https://app.writer.com/mcp/oauth/callback
https://mcp.stensul.com/<your-instance>/oauth/callback

  1. Leave PKCE off.

  2. Select the scopes your team needs. The first four cover drafting. The last three turn on the image gallery and audience versions; a tool whose scope is missing returns a 403. See scopes.

    • libraries:read: read libraries
    • emails:read: read emails
    • emails:write: write emails
    • images:write: upload images (labeled Write images)
    • dam:read: browse the image gallery (labeled Read Dam images)
    • dynamic-content:read: read segment sets
    • dynamic-content:write: apply segment sets and write segment content

    The list shows other scopes too, such as capabilities:read, modules:write, users:read and roles:read. Leave them unchecked: the MCP doesn’t use them.

  3. Save. Copy the Client ID and Client Secret immediately. The secret is shown once.

2. Add the connector in Writer

  1. In Writer, open Connectors and click Custom connector (Beta).
  2. Choose Connect to a MCP server.
  3. Enter the MCP Server URL: https://mcp.stensul.com/<your-instance>/mcp
  4. Choose OAuth and fill in:
Field Value
Authorization URL https://mcp.stensul.com/<your-instance>/oauth/authorize
Access Token URL https://mcp.stensul.com/<your-instance>/oauth/token
DCR (Dynamic Client Registration) No
OAuth2 Client ID From step 1
OAuth2 Client Secret From step 1
  1. Save the connector.

3. Sign in and draft an email

Each person finds the Stensul connector in Writer, connects it, logs in to Stensul and approves. Then:

Using Stensul, draft an event invitation email in the <library name> library
for our customer roundtable on November 12. Keep the subject line under 50
characters. Return the edit link and a preview.

You’re done when Writer returns an edit link to the draft. In Writer the preview comes back as a static image.

If something goes wrong

What you see Fix
Redirect error at sign-in Both redirect URIs must be present and exact
Writer asks for a client secret Expected. Create the Stensul connection with PKCE off so it has one
“couldn’t connect” before setup finishes An error on Writer’s side. Wait a few minutes, check every URL and ID, then retry
It worked before, now asks you to sign in Your authorization expired. Sign in again
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