Constraint & Helper Tags

Inside Constrained column, tags are attached to the field name to indicate which checks or helper macros apply. These are the tags you’ll see:

• has_one From has_one = <field> constraints. Ensures the current account’s stored pubkey equals another account’s key.
  Use: Ownership/binding check.

• address From address = <expr> constraints. Pins the account to a specific known address (often sysvars).
  Use: Ensure the provided account is exactly one expected address.

• constraint From constraint = <predicate>. Free-form runtime conditions the program checks before continuing.
  Use: Anything from balance thresholds to relationship checks not covered by has_one.

• owner From owner = <Program> constraints in the attribute. Enforces the owning program for an account (e.g., Token Program).
  Use: Ensure account is controlled by the right program (critical for token/state integrity).

• spl Detected when SPL helper attributes are present on the field, e.g.:

  • associated_token::mint = ...
  • associated_token::authority = ...
  • token::mint = ..., token::authority = ...
  • mint::authority = ..., mint::freeze_authority = ..., mint::decimals = ...
    Use: These helpers encode common SPL invariants; presence of spl implies ATAs and token relationships are being checked declaratively.

Formatting reminder: field(tag1,tag2) indicates multiple constraint types apply to the same field.

See more about constraint here