When I name a sound-effects file under UCS, which of CatID, FXName, CreatorID, SourceID, UserCategory, VendorCategory and UserData must I provide, and which are optional?

The only secondary text found that reproduces the operative filename wording is a vendor page (JamSoft SampleSort support), which says two things: the basic structure 'requires at least four blocks' (CatID_FXName_CreatorID_SourceID), and in its conclusion that the only requirement is a valid CatID at the head with the rest 'completely optional'. UserCategory, VendorCategory and UserData are the three optional blocks. The official document itself could not be retrieved (candidate -01), so this answer is a secondary reading and carries an unresolved internal tension. Curator qualifications: The JamSoft wording verifies, and its apparent tension resolves on a close reading: 'requires at least four blocks' describes the basic structure, while the CatID paragraph and the conclusion state the CatID is 'the only requirement' and the rest is 'completely optional'. This is a secondary vendor reproduction of the official 8.2.1 text. Read the 'four blocks' sentence as describing the structure, not as a requirement: the vendor states CatID is the only requirement. Keep the tension noted as wording ambiguity. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://www.jamsoft.co.uk/samplesort/support/universal-category-system/",
      "note": "work/jamsoft.html JamSoft SampleSort UCS support page (implements 8.2.1, January 2024)"
    },
    {
      "url": "https://audio-tool-kit.com/blog/ucs-naming-convention",
      "note": "work/jamsoft.html JamSoft SampleSort UCS support page (implements 8.2.1, January 2024)"
    },
    {
      "url": "https://sonofex.com/ucs/",
      "note": "work/jamsoft.html JamSoft SampleSort UCS support page (implements 8.2.1, January 2024)"
    }
  ]
}