Calendly

SCHEDULING OPERATIONS

Enterprise-owned OAuth for the full scheduling lifecycle.

Forty tools across event types, availability, meetings, routing, webhooks, organizations, and compliance.

The Quilr-built Calendly MCP connects with a Calendly OAuth application that your organization owns. A Calendly administrator creates the application and gives its Client ID and Client Secret to the MCP Gateway. Each Calendly user then authorizes their own account in the browser.

Custom MCP only

These steps are for the Quilr Calendly MCP at https://calendly-custom.mcp.quilr.ai/mcp. Calendly's official MCP (https://mcp.calendly.com/) uses Dynamic Client Registration and does not accept manually created OAuth credentials.

Tools

The MCP exposes 40 tools when the full scope set below is enabled, across event types, availability, meetings, routing, webhooks, organizations and compliance. Some tools also depend on the Calendly plan and the authorizing user's role: routing forms need a qualifying Teams plan, and direct scheduling needs a paid plan.

Keep write and external-action tools off in Tool visibility until they are approved.

Setup

Item	Requirement
Calendly developer account	Create one with GitHub or Google at the developer portal. It is separate from your normal Calendly account.
Application owner	An administrator responsible for credential storage, rotation and scope approval.
Environment	Start with Sandbox. Create a separate Production application before using real data.
Redirect URI	The exact OAuth callback URL QuilrAI shows. Production is normally https://mcpgateway.quilr.ai/oauth/callback.

1. Create the Calendly OAuth application

1. Open the Calendly developer portal and create a new OAuth application, for example QuilrAI Calendly - Sandbox.
2. Select Web as the application kind, and Sandbox or Production.
3. In Redirect URI, paste the exact callback URL from QuilrAI. Production applications require HTTPS. Do not add a trailing slash unless QuilrAI's URL has one.
4. Select the scopes below, then create the application.
5. Copy the Client ID and Client Secret immediately into your secret manager.

Copy the secret immediately

Calendly shows the Client Secret only when the application is created. Do not confuse it with the Webhook signing key.

2. Choose scopes

New Calendly applications have no API access until scopes are selected. Read-only tools need:

users:read
organizations:read
event_types:read
availability:read
locations:read
scheduled_events:read
routing_forms:read

The full tool surface requests this set:

users:read
organizations:write
event_types:write
availability:write
locations:read
scheduled_events:write
scheduling_links:write
shares:write
routing_forms:read

Calendly write scopes include the matching read permission. The gateway requests every scope the MCP advertises, and Calendly rejects the whole authorization if any one of them is not enabled on your application, so keep the two lists identical. Do not add a redundant read scope next to its write scope.

3. Add the server to the MCP Gateway

1. Go to Settings > AI Gateway > MCP Gateway and click Add MCP server. Choose Remote server.
2. Enter a Name such as Calendly Custom, a Slug such as calendly-custom, and Transport URL https://calendly-custom.mcp.quilr.ai/mcp.
3. Keep Auto-detect (recommended) under How the gateway signs in and click Probe and continue.
4. In Connect with OAuth, confirm the OAuth callback URL matches the one in Calendly, enter the OAuth client ID and OAuth client secret, and click Create MCP.
5. Connect OAuth once as an administrator, review the permissions in Calendly and approve.

Do not choose OAuth passthrough for this server. The gateway holds your application credentials, runs the authorization-code flow with PKCE, stores and refreshes each user's tokens, and sends only the resulting Calendly bearer token to the MCP.

4. Connect a client and verify

Point clients at the server's Quilr gateway URL, not the upstream URL or Calendly's official URL. In Cursor, use a short key because long combined server and tool names can be filtered:

{
  "mcpServers": {
    "cal": {
      "type": "http",
      "url": "https://mcpgateway.quilr.ai/YOUR-CALENDLY-SLUG/mcp"
    }
  }
}

For Claude, add a custom connector with the same URL and leave its OAuth fields empty. Then run a read-only check:

Use the Calendly Custom MCP. Get my Calendly account context, list my active
event types, and show the first five available times for the first event type.
Do not create, update, cancel, invite, share, or book anything.

Confirm the returned user and organization are the ones you intended, and that no scope error appears.

Credential rotation

• Redeploying the Calendly MCP does not require users to reconnect. A gateway redeployment also keeps connections when its database, encryption key, public callback URL, backend record and OAuth token state are all retained.
• Update the saved client ID and secret if you replace the Calendly application or rotate its credentials.
• Users must reconnect after their grant is revoked, scopes change, their latest refresh token is lost, the gateway connection is deleted, or the public OAuth identity changes. Calendly refresh tokens are single-use and rotate; the gateway stores the new one after each refresh.

Troubleshooting

Error or symptom	Likely cause	Fix
invalid_client before consent	Wrong client ID or secret, or a secret from another application	Re-enter the matching credentials. If the secret was not saved when the app was created, issue replacement credentials through the Calendly developer portal.
invalid_scope	The MCP advertises a scope not enabled on your application	Make the enabled and advertised scopes identical, then reconnect.
Redirect URI error	Callback differs in environment, scheme, path or trailing slash	Paste QuilrAI's callback exactly into Calendly and reconnect.
403 or missing-scope error	The application or the user's grant lacks a scope	Add the minimum scope and reconnect.
Unexpected account connected	The browser was signed in to another Calendly account	Disconnect, sign out of that account and reconnect.
No tools, or Loading tools	Wrong upstream URL, OAuth not completed, or the client uses Calendly's official URL	Check both URLs, finish Connect, refresh tools and restart the client entry.
Reconnect requested after working previously	Grant revoked, refresh token invalidated, credentials rotated, gateway OAuth state lost, or callback/resource identity changed	Preserve gateway state during deployment. Otherwise fix the configuration and reconnect the affected user.
A routing, booking or organization tool fails	Plan or role does not permit the operation	Check the Calendly plan, role and scope.

References: Creating an OAuth app, Scopes, Refresh token rotation.

Compared with the official server

Provider-native

Choose official for DCR clients

Use Calendly's hosted server when your MCP client supports Dynamic Client Registration and provider-managed onboarding fits your environment.

• Provider-hosted remote MCP
• Modern DCR-native onboarding

Quilr-managed

Choose Quilr for owned credentials

Use Quilr when the enterprise must own the OAuth application or the client depends on pre-registered credentials.

• Customer-owned OAuth app
• Forty lifecycle tools behind gateway policy

Decision signalThe deciding factor is credential ownership and client compatibility, not scheduling feature coverage.

Capability	Calendly Official MCP	Quilr Calendly
Hosted remote MCP	✅	✅
Dynamic Client Registration	✅ Required	-
Customer-owned OAuth application	-	✅
Pre-registered client credentials	-	✅
Scheduling read/write	✅	✅
Routing and availability	✅	✅
Webhook and organization workflows	✅	✅
Gateway guardrails and audit	Via gateway	✅ Native deployment model

Use Calendly's official server for modern DCR-compatible clients. Use Quilr when the organization must own the OAuth application or the client requires pre-registered credentials.