Run tools without a conversation

Use a function for custom JavaScript, an API tool for a saved HTTP request, an integration action for a connected service, or an MCP tool for a tool on a connected server. Integration actions use the project’s Draft connection and their catalog tool name; they do not need to be attached to the agent first.

Call the resource’s schema operation before execution. For a function:

vf function get-schema --project-id "$PROJECT_ID" --environment-alias "$ENVIRONMENT" --function-id "$FUNCTION_ID"

Functions and API tools require a string value for every declared input and reject unknown names. Integration and MCP inputs follow their schemas. Supply actual values rather than conversation-variable tokens. A project secret can be supplied as {secret_name}; see input and secret rules.

For a function whose schema declares a string input named customer_id, use:

vf function execute --project-id "$PROJECT_ID" --environment-alias "$ENVIRONMENT" --function-id "$FUNCTION_ID" --inputs '{"customer_id":"test-customer"}'

This input name is illustrative: replace it with your function’s declared inputs. The equivalent REST request is:

curl --request POST "https://realtime-api.voiceflow.com/v1/stable/function/$FUNCTION_ID/execute?projectID=$PROJECT_ID&environmentAlias=$ENVIRONMENT" \
  --header "Authorization: Bearer $VF_TOKEN" \
  --header 'Content-Type: application/json' \
  --data '{"inputs":{"customer_id":"test-customer"}}'

Use your deployment’s API base URL from the API reference. To use an AI client, ask it to discover the function schema and execute with these explicit inputs. The function MCP reference shows the structured invocation.

Check success, error, and truncated, then inspect output. A function returns output variables, its selected path, and traces. An API tool returns the upstream HTTP status, headers, and body. Integration and MCP tools return their tool result. An HTTP 200 response can still contain success: false.