genre-essentials

name	genre-essentials
description	Explains what makes a genre sound like itself — the harmonic, melodic, rhythmic, and timbral signatures of blues, jazz, pop, modal, folk, and others. Pure catalog skill. Use when a learner asks 'what makes blues blues' / 'what defines jazz harmony' / 'how do I write a country progression'.
triggers	["what makes blues","what makes jazz","what makes country","what makes pop","what makes rock","what defines a genre","blues progression","jazz progression","country progression","modal sound","pop progression","folk chord","genre essentials"]
license	internal
compatibility	{"agent-framework":">=1.0.0-preview","microsoft-extensions-ai":">=10.5.1"}
metadata	{"authoring-style":"deterministic-catalog","origin":"drafted in skills-dev/ as Tier 4 catalog skill (skill-stewards 2026-05-05)","evidence-kinds":["catalog_lookup"]}

Genre Essentials — What Makes Each Genre Sound Like Itself

Catalog skill. When a user asks what defines a genre's sound, match to one of the templates below. Each template lists the harmonic / melodic / rhythmic / timbral signatures so the answer covers more than just "play these chords".

🎷 Blues

Harmony: 12-bar blues form (I7 – I7 – I7 – I7 – IV7 – IV7 – I7 – I7 – V7 – IV7 – I7 – V7), all dominant-7 chords (no triads, no major-7). Quick-change variant adds IV7 in bar 2. Melody: blues scale (1, b3, 4, b5, 5, b7), heavy use of bent and slid notes, b3-and-3 ambiguity. Rhythm: shuffle / swing eighth notes, often a strong backbeat on 2 and 4. Timbral: tube-amp grit, slide guitar, harmonica, expressive vibrato.

🎺 Jazz

Harmony: extended chords (9ths, 11ths, 13ths, alterations), tritone substitution, backdoor cadences, modal interchange. ii-V-I is the signature cadence (replace V-I with ii-V-I anywhere). Heavy use of secondary dominants (V7/ii, V7/V). Melody: chromatic approach tones, target chord tones on strong beats, "out" playing over chord changes. Rhythm: swung eighth notes (long-short triplet feel), syncopation, phrase ends on weak beats. Timbral: hollow-body / archtop guitar, walking bass, brushed drums, muted brass.

🎵 Pop

Harmony: 4-chord loops are king — axis (I-V-vi-IV) is the most-recorded progression of the 21st century. Diatonic only; minimal chromaticism. Borrowed iv from parallel minor adds emotional lift. Melody: hooks that fit the chord changes; minimal range, repeatable rhythms. Rhythm: 4/4, strong backbeat, quantized to 16ths. Timbral: clean tones, layered synths or guitars, tight low end.

🎻 Folk / singer-songwriter

Harmony: open-position chords (C, G, D, A, Em, Am, Dm), modal-mixture borrowed chords (bVII, bVI). Often capo-driven so the same shapes work in many keys. Melody: pentatonic, often vocal; melodic ornaments on phrase ends. Rhythm: 4/4 or 6/8 (waltz), strummed or fingerpicked. Timbral: acoustic guitar, banjo, mandolin, fiddle — natural / unprocessed.

🌀 Modal (jazz-modal, post-bop, Norah Jones-y)

Harmony: STATIC harmony — one chord (or two) for many bars. Vamps in Dorian, Phrygian, Lydian. Avoid V-I cadences (they imply tonal motion). Melody: emphasises modal characteristic intervals — Dorian's natural 6, Lydian's #4, Phrygian's b2. Rhythm: often spacious, less rhythmic urgency than tonal jazz. Timbral: open voicings (quartal stacks), pedal-tone bass.

🤠 Country

Harmony: I-IV-V dominates, with vi as the relative-minor variation. Often quick changes between I, IV, V; dominant-7 versions of each are common. Melody: pentatonic with chromatic passing tones; pedal-steel-style bends. Rhythm: 2-feel ("boom-chick" alternating bass), shuffle in honky-tonk subgenre. Timbral: acoustic + Telecaster, pedal steel, fiddle, twangy reverb.

🎸 Rock (classic / hard / prog)

Harmony: I-bVII-IV ("mixolydian rock") and i-bIII-bVII (minor) common. Power chords (root + fifth, no third). Modal-mixture borrowing prevalent. Melody: minor pentatonic + blues scale; Phrygian for darker subgenres. Rhythm: 4/4 with strong backbeat; often syncopated guitar parts. Timbral: distorted electric guitar, big drums, prominent bass.

When to call other skills

• "What chords are in [key]?" → scale-info returns the scale notes; the canonical diatonic-set table is in the circle-of-fifths and key-identification skills' DiatonicSet outputs.
• "What key is this progression in?" → key-identification.
• "How do I darken / brighten this progression?" → progression-mood (modal-interchange techniques).
• "Modal harmony" deeper dive → modes.

When to refuse / clarify

• Highly subgenre-specific requests (synthwave, vaporwave, math rock) — pick the parent genre and note that subgenre adds further constraints (often timbral / production rather than harmonic).
• "What's the BEST genre" — refuse the value judgment; offer the descriptive comparison instead.

Out of scope

• Production / mixing advice — out of scope.
• Lyric / song-form advice — out of scope.
• Detailed historical evolution — defer to dedicated music-history sources.