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Subgenre overlays

Per-subgenre carve-outs for the universal rubric.

The 12 metrics are universal — they apply across every tradition. But certain subgenres have explicit lyrical conventions the universal rubric reads as failures. Country radio choruses repeat the title four times by design. Reggaeton hooks lock to the dembow pulse. Hip-hop bars layer polysyllabic internal rhymes the universal Prosody metric doesn’t reward at full band. Per- subgenre overlays apply +/- adjustments without forking the standard.

How overlays work

  • Same 12 metrics. Same 0-100 scale. Same anti-inflation rules.
  • When the song’s genre matches an overlay, the overlay’s carve-outs apply: specific metrics get band-shifted up or neutralized when the canonical move of that subgenre would otherwise trigger a deduction.
  • The composite is still 0-100 against the universal scale. A 95 in country-radio means the same thing it means in fado: canonical-band work in its tradition.
  • Overlays document EARNED CONVENTIONS — moves that read as cliche elsewhere but are canonical in this subgenre. Implementers re-scoring outside the overlay shouldn’t penalize these moves.

The overlay system is content-driven. Adding a new overlay is one entry in src/lib/rubric-overlays.ts. Independent implementers under CC BY 4.0 can publish their own overlays + cite back here.

  1. Country Radio

    parent genre: country

    Country radio is a form with explicit lyrical conventions: the chorus title repeats four times by design, the bridge resolves to the title, the verses build named-anchor specificity (truck, town, woman, work) toward the chorus's emotional thesis. The universal rubric's Anti-Platitude rule + Memorability test can flag canonical country radio moves as failures. The overlay marks those moves as canonical when they appear in their proper structural position.

    Carve-outs

    • M11 · Memorability

      Raises band

      The title-repeats-4x chorus pattern is the form. Memorability reads the recurrence as structural commitment, not redundancy. M11 lands at 90+ when the title lands clean each return, even with high repetition.

    • M4 · Economy

      Neutralizes

      Chorus repetition does not penalize Economy. The metric continues to penalize FILLER (lines that exist only to rhyme), but accepts canonical title-restatement as a feature.

    • M12 · Genre

      Raises band

      Hank-Williams + George-Jones + Strait + Loretta calibration. A country radio lyric that uses the form's vocabulary (truck, dirt road, mama, the bottle, the porch, the church) earns Genre Authenticity at the canonical band when those vocabulary items are doing real work — a "truck" with a named transmission + a named radio station scores higher than a "truck" used as decoration.

    Earned conventions

    • Title repeats 4x in the chorus — when each repeat lands clean, this is structural commitment, not redundancy.
    • First-person at the bar / on the porch / in the truck — first-person physical-place specifics are canon, not template.
    • The title as the last line of every chorus + every bridge resolution.

    Anchors in the corpus

    Canonical S-band examples for this subgenre live at: corpus-003, corpus-001

  2. Reggaeton

    parent genre: latin

    Reggaeton is rhythm-first lyric: the words ride the dembow's 3+3+2 pulse, repetition is the engine, and short phrases compound in 4-bar units. The universal Economy of Language metric reads short repetitive phrases as filler; under the reggaeton overlay, those phrases are the form's rhythmic substrate. The metric continues to penalize FILLER but accepts canonical phrase-on-the-pulse repetition as a feature.

    Carve-outs

    • M4 · Economy

      Neutralizes

      Phrase-on-the-pulse repetition (the same 2-4 word phrase compounding across 4-bar groups) is the rhythm, not filler. M4 reads at canonical band when the repetition is rhythmically locked + sonically distinct.

    • M11 · Memorability

      Raises band

      The hook is short by design (1-3 words, often the title). M11 reads at S-band when the short hook earns its return through phonemic distinctiveness + dembow lock-in.

    • M1 · Prosody

      Raises band

      Lyric stress lands ON the dembow's accent beats (1, 1.5, 3 in the 4-beat measure). Universal Prosody reads stress-pattern; reggaeton overlay reads stress AGAINST the dembow specifically.

    • M5 · Specificity

      Raises band

      Specificity in reggaeton is body + place + time-of-night, not narrative-plot detail. A reggaeton lyric with 'el club / la cintura / hasta abajo / esta noche' is specific by the form's standard, even if it lacks a story-arc proper-noun.

    Earned conventions

    • Short hook repeated 4-8x per chorus on the dembow lock — canonical, not redundant.
    • Body-instructional vocabulary (move, dance, lower, closer) operating as specificity, not abstraction.
    • Spanglish code-switch within the same line, when the switch lands rhythmically.

  3. Hip-Hop (high-density bars)

    parent genre: hiphop

    Hip-hop's central craft variable is words-per-bar + internal-rhyme density. The universal Prosody metric reads stress patterns but doesn't reward high-density polysyllabic internal rhyme; under the hip-hop overlay, density is the form. The universal Voice metric reads featured-verse contrast as POV drift; under the hip-hop overlay, the featured verse is canonical multi-narrator structure (now also captured by the v1.2.0 M8 "intentional POV" refactor).

    Carve-outs

    • M1 · Prosody

      Raises band

      Words-per-bar (typical hip-hop range: 16-32 syllables per 4-beat bar) is rewarded. Internal rhyme density (multi-syllable rhymes hitting on the 2 and the 4) reads at S-band. Universal Prosody floor still applies — bars that scan poorly fail regardless of density.

    • M8 · Voice

      Neutralizes

      Featured-verse POV switches are canonical structure, not drift. (M8 v1.2.0's "intentional POV" already captures this; the overlay makes it explicit for hip-hop scoring.)

    • M6 · Imagery

      Raises band

      Hip-hop imagery reads through punchline + double-entendre + cultural-reference layering. A line that lands as one image AND a second meaning earns Imagery Originality at the canonical band even when each image alone is conventional.

    • M3 · Rhyme

      Raises band

      Multi-syllable polysyllabic rhyme + internal rhyme + chains of 3-4-5 successive rhymes are the form. The universal Rhyme Intelligence metric reads at S-band on density that would feel forced in a pop song.

    Earned conventions

    • Polysyllabic internal-rhyme chains across a single bar — canonical, the form's central display of skill.
    • Featured-verse contrast (Verse 2 in a different MC's voice) — structural, not POV failure.
    • Layered-meaning punchlines where the literal + the metaphorical both land — canonical Imagery, not over-loading.

    Anchors in the corpus

    Canonical S-band examples for this subgenre live at: corpus-005

Future overlays

Planned next, in roughly priority order:

  • Worship + Gospel — ritual repetition, communal first-person plural, scriptural quotation as canonical move.
  • K-pop multi-voice — multiple character voices in one chorus as canonical structure (now partially captured by M8 v1.2.0).
  • Trap / Drill — short bars, punctuation-style ad-libs as rhythmic content, brand + place specificity in lieu of narrative.
  • Hyperpop — deliberate pastiche + glitch + maximalism as form.
  • Bollywood / Hindi film — metaphor density as canon, dual-language (Hindi-Urdu) register, song-as-narrative-pause-in-film.
  • Country trap and other crossovers — overlay composition is allowed (apply two overlays for hybrids).

Submit a proposed overlay via support@songforgeai.com with the subgenre name + 5+ canonical exemplars + the carve-outs you propose.