It would much more intuitive if a default_value for config schema populated the UI input yaml box. I was quite surprised when it didn't. Sorry if there's a good Engineering / Data Engineering reason for why that isn't a good design choice. For me that default value is likely to be a bit of communication between a more technical person and a less technical person (who won't be looking at the code). I want to offer them something that would work, but give them the option to change it if they know what they're doing (and for that to be obvious). It is not at all obvious that there's a value that could be changed when the config validation is happy and nothing is populated in the input box.

@asset(
    config_schema={
        'pretrained_model_name': Field(
            str,
            default_value='bionlp/bluebert_pubmed_mimic_uncased_L-12_H-768_A-12',
            description='Hugging-face model from <https://huggingface.co/models>',
        ),
    },
)

Agreed - I phrased the same request recently

This could be done with "scaffold all config" button in the launchpad. I agree here but i have also started removing default values from the config schema and instead supplying them through the default job config exclusively. Helps keep all the relevant logic in one spot in the code

definitely a piece of feedback we've received often, and having a better solution here is definitely on the radar. https://github.com/dagster-io/dagster/discussions/7868