The functions that have Codelenses are those that use AWS Lambda-function handler syntax.

CodeLenses

A handler is a function that Lambda calls to start execution of a Lambda function. These CodeLenses enable you to locally run or debug the corresponding serverless application. CodeLens actions in the Toolkit include:

• Configure, for specifying function configurations such as an event payload and environment variable overrides.
• Run Locally, for running the function without debugging.
• Debug Locally, for running the function with debugging.