Save External MCP Registration

Note

This tool is available by default on the following MCP servers: Dynamics 365 Customer Service. The tools and examples in this documentation illustrate current capabilities. Tool names, descriptions, parameters, response formats, and available functionality can change over time.
When you build agents, integrations, or orchestration logic, don't hard-code dependencies on specific tool names, parameter structures, tool metadata, or response schemas. Instead, design your solution to discover and use available tools at runtime.
As the platform evolves, Microsoft might add, remove, rename, or modify tools and tool metadata. Designing against capabilities rather than specific tool identifiers helps maintain compatibility across service updates.

This capability works behind the scenes when you add or edit an external MCP tool server registration from the registration management widget.

What it does

When you fill out the registration form in the MCP server management widget and select Save, this tool persists the registration to your Dynamics 365 environment. It handles both creating new registrations and updating existing ones.

The tool validates the endpoint URL for security, checks that the authentication scope is allowed, enforces the registration cap (20 per environment), and prevents duplicate endpoints or tool prefixes. On success, it stores the registration and refreshes the Service Agent's tool list so the new server's tools become available.

Try prompts like

Not applicable. This tool is called automatically when you save a registration from the management widget. It is not invoked by typing a prompt.

What you'll see in chat

The registration widget updates to confirm the save succeeded, showing the registration ID and whether it was created or updated. If validation fails (for example, a duplicate endpoint or a reserved tool prefix), the widget displays an error message explaining what to fix.

Helpful tips

• You must run Test Connection before saving a new registration. The tool snapshot from the test is what gets persisted.
• Each server endpoint can only be registered once. Remove the existing registration first if you need to re-register the same URL.
• Tool prefixes must be unique across all registrations in your environment.
• Saving a registration invalidates the tool cache, so the updated tools take effect on the next conversation.

What happens next

After saving, the registration widget returns to the list view. You can:

• "Test the connection again"
• "Edit the registration I just saved"
• "Add another MCP server"

Does this change data?

Yes, this changes data.

Saving a registration creates or updates a configuration record in your Dynamics 365 environment and refreshes the Service Agent's available tool list.

Prerequisites

This tool requires the following:

• System Administrator or Copilot Service administrator role

Tool summary

Property	Value
User-facing name	Save External MCP Registration
Internal tool name	save_mcp_registration
Purpose	Persists a new or updated external MCP server registration

Tool behavior

Persists a new or updated external MCP server registration. This is a widget support tool invoked automatically when users interact with the extensibility registrations widget. It is not intended for direct invocation by the model.

Annotations

Annotation	Value	Meaning
readOnlyHint	false	This tool creates or updates registration data.
destructiveHint	false	Updates are non-destructive (upsert pattern).
idempotentHint	true	Repeated calls with the same input produce the same result.
openWorldHint	Not set	Uses default.

Input concepts

Registration object

Input	Description	Required
displayName, name, endpoint, authScope, mode, toolPrefix, tools	Contains the server registration details including displayName, name (unique identifier), endpoint (HTTPS URL), authScope (Entra OBO target scope), mode, toolPrefix, and tools array.	No

Registration ID

Input	Description	Required
id	id (optional). When provided, updates an existing registration; when omitted, creates a new one.	No

Organization URL

Input	Description	Required
orgUrl	orgUrl (optional). Overrides the currently selected environment URL.	No

Response and UI behavior

This MCP tool is supported by an MCP App.

Response type

Widget update

The widget refreshes to show the saved registration.

Routing notes

This tool is exclusively called by the manage_mcp_registration widget. Do not invoke it directly.

Related tools

Tool	Relationship
manage_mcp_registration	The launcher tool that opens the registration widget
delete_mcp_registration	Removes a registration
test_mcp_registration_connection	Tests connectivity before saving

Data mutation classification

Write (upsert). Creates or updates an external MCP server registration in the org-scoped registration store.