Why can't I sort or filter metrics with certain characters?

Metric names in W&B must follow GraphQL naming conventions to ensure they can be properly sorted and filtered in the UI.

Valid metric names

• Allowed characters: Letters (A-Z, a-z), digits (0-9), and underscores (_)
• Starting character: Names must start with a letter or underscore
• Pattern: Metric names should match /^[_a-zA-Z][_a-zA-Z0-9]*$/

Metrics that don’t follow these rules may not be sortable or filterable in the W&B UI.

Examples

Valid metric names:

with wandb.init() as run:
  run.log({"accuracy": 0.9, "val_loss": 0.1, "epoch_5": 5})
  run.log({"modelAccuracy": 0.95, "learning_rate": 0.001})

Invalid metric names (avoid these):

with wandb.init() as run:
  run.log({"acc,val": 0.9})  # Contains comma
  run.log({"loss-train": 0.1})  # Contains hyphen
  run.log({"test acc": 0.95})  # Contains space
  run.log({"5_fold_cv": 0.8})  # Starts with number

Recommended solution

Replace invalid characters with valid characters such as underscores:

• Instead of "test acc", use "test_acc"
• Instead of "loss-train", use "loss_train"
• Instead of "acc,val", use "acc_val"

For more information, see Metric naming constraints.