You are developing an application that analyzes invoices by using Azure Content Understanding in Foundry...

The correct parameter is analyzer_id . The Azure AI Content Understanding Python SDK uses the ContentUnderstandingClient.begin_analyze() method to submit content for processing. Microsoft defines the method signature with analyzer_id as the required identifier that specifies which analyzer should process the supplied input.

Therefore, the code should be completed as:

poller = client.begin_analyze(analyzer_id= " invoiceAnalyzer " , ...)

A custom analyzer encapsulates the configuration that determines how Content Understanding interprets the source content and which fields or structured information it extracts. Because the analyzer has already been created with the name invoiceAnalyzer , that value is supplied through analyzer_id when the analysis operation begins.

extraction_type is not the parameter used to select an analyzer. model_name would refer conceptually to an underlying AI model, but Content Understanding analysis is invoked through an analyzer abstraction rather than by specifying a model directly. Likewise, schema_id does not identify the analyzer to execute.

Microsoft ' s custom-analyzer guidance explicitly demonstrates client.begin_analyze(analyzer_id=analyzer_id, inputs=[...]) , confirming the required SDK pattern