Domain 2 of 3 · Chapter 6 of 15

Add a tool by using an existing custom connector

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Included in this chapter:

  • The connector already exists, so the work starts elsewhere
  • Two grants, two portal pages, two failure symptoms
  • Adding the operation as a tool
  • The three sections of the tool configuration page
  • Writing a description the orchestrator can act on
  • Who the call runs as
  • When the API changes underneath the tool
  • How these choices show up in questions

Four ways to reach one REST API from an agent

PropertyExisting custom connector operationPrebuilt connector operationREST API tool (preview)Send HTTP request node
Where it is definedPower Apps maker portal, from an OpenAPI definition, Postman collection or from scratchPublished by Microsoft or a partner; nothing to defineGuided OpenAPI v2 upload inside Copilot StudioTyped directly on one topic's canvas
Reuse beyond this agentCopilot Studio, Power Automate, Power Apps and Azure Logic Apps; connectors created in Logic Apps are the exception and do not carry overCopilot Studio, Power Automate, Power Apps and Azure Logic AppsEnvironment Tools page, so other agents in the environment onlyNone; the configuration belongs to the topic that holds it
Prerequisite before the agent can use itConnector published and shared with the maker (Can view or Can edit)A licensed plan for premium connectors; standard connectors are on all plansAn OpenAPI v2 specification for the endpoints you wantThe URL, method and, where needed, sample response data
Credential storyA Power Platform connection, End user or Maker-provided credentialsA Power Platform connection, End user or Maker-provided credentialsConfigured on the tool when the API is addedHeaders you populate yourself, ideally from environment variables
Classified by connector data policiesYes; admins classify custom connectors alongside prebuilt ones as Business, Non-Business or BlockedYes; classified as Business, Non-Business or BlockedNo published connector classification; data policies classify prebuilt and custom connectorsNo published connector classification; data policies classify prebuilt and custom connectors
Production readinessNo preview label on its product pageNo preview label on its product pagePreview; Microsoft states it is not suited for production useNo preview label on its product page

Decision tree

An existing custom connector wraps the API you needIs the connector shared with you (Can view or Can edit)?noShare it first: Data > Customconnectors > Invite another useryesDoes a connection for it already exist here?noCreate new connection, thenselect Add and configureyesShould orchestration choose the moment it runs?noClear dynamic use; call it froma topic Action nodeyesDoes each user hold an account in the target system?noMaker-provided credentials(needs an authenticated channel)yesEnd user credentials, orchestratedat agent level
Cheat sheet

Cheat sheet

  • Add a specific custom connector operation as a tool
  • Grant organizational view and share permission
  • Create or select the connector connection
  • Reuse custom connectors across agents
  • Write a discriminating connector tool description
  • Support both dynamic and explicit connector calls
  • Control how connector inputs are populated
  • Refresh connector consumers after an API schema change

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Also tested in

References

  1. Custom connectors overview
  2. Add tools to custom agents
  3. Understand connector and REST API tools in Copilot Studio
  4. Custom connector parity in data policies
  5. Share a custom connector in your organization
  6. Add prebuilt and custom connector tools to an agent
  7. Use connectors in Copilot Studio agents
  8. Configure user authentication for tools
  9. Configure authentication for connector tools
  10. Create and manage connections
  11. Copy an environment