TYPE: rule
PRIORITY: high

The Ionian (major scale) interval formula is:

W W H W W W H

To construct a major scale:
- Start on the root note
- Apply each interval step in sequence

TYPE: rule
PRIORITY: high

When constructing scales:

Each note must use a different letter name in sequence.

Example letter sequence:
A B C D E F G

Do not repeat or skip letters.

Accidentals (#, b) are used to satisfy interval distances,
not to change letter sequence.


TYPE: rule
PRIORITY: high
DOMAIN: logic_constraints
TOPIC: Sequence Integrity
RULE: Every element in a 7-element diatonic set MUST use a unique leading character (A, B, C, D, E, F, G). 
CORRECTION LOGIC:
- If a calculation yields "C#" but the previous element was "B", and the next letter required is "C", "C#" is VALID.
- If a calculation yields "C#" but the letter "C" was already used, you must find the ENHARMONIC equivalent that uses the next available letter (e.g., if "D" is the next letter, use "Db").
- In the specific case of F# Major, the sequence MUST be F#, G#, A#, B, C#, D#, E#. Note: E# is the only valid spelling for the 7th degree.

TYPE: fact
PRIORITY: high
ALPHABETICAL_ANCHOR: The master letter sequence is a repeating loop: [..., A, B, C, D, E, F, G, A, B, ...].
When deriving any 7-note sequence, you must select 7 consecutive letters from this anchor as your labels before determining their sharp/flat status.