This to me feels more like a developer skills issue than a problem with the LLM. At my day job, we banned using untyped data structures like this entirely well before LLMs because no one could read code that passed them around.

You could use a data structure that better articulates an optional field, like a dataclass with type hints or a pydantic model. Then you, your coworker, and the agent alike, aren’t guessing at whether the key’s value is optional.

Another example in this vein is having many optional parameters on a function or api route, that drive behavior deeply nested in the application logic. Or maybe they were there for testing and never deleted. No one comes across this code next and understands it easily. How could you expect a LLM to understand it, either?

I find it funny when people blame the LLM for dog shit code, but at the same time have a pollock painting of code they load into its context, and are like “put a person in the horse and carriage!” And the LLM is like “bro I just see dots and squiggles but you asked so boom!”

The square bracket version tells the reader it's required, the .get version tells the reader it's optional. Kind of the reason both exist in the language (the .get version has an optional second argument to return instead of None when the key is missing).