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Loci: A 15-Prompt Thematic Invention Tool for Composers

A composer's-block plugin that systematically generates fifteen distinct thematic starting points from the treatise's fifteen invention loci, leading with the two most powerful (notation-based and description-based), so a stuck composer gets divergent motif seeds in minutes.

Social SciencesLaw and Political Science
Music composition software and music education (composer productivity tools)

Concept

A creativity tool delivered as a plugin for notation software (Sibelius, Dorico) and as a standalone web app. The composer enters a brief — or nothing at all — and the tool walks through fifteen systematic "places to search" for thematic material (loci), generating a distinct starting point for each: a motif derived from the notation itself (Locus notationis), one derived from describing the subject or scene (Locus descriptionis), and thirteen more from the treatise's full set. Each prompt can emit a short MIDI motif sketch plus written guidance, so a blocked composer gets 15 divergent seeds instead of an empty staff. The same loci set is licensable to AI-music companies as a structured prompt library to diversify generated themes.

Why now

The treatise [0] explicitly presents its fifteen loci as "aids for thematic invention, especially when creativity is low" — a documented, purpose-built use case for a creativity-support tool — and it names the two most significant loci (Locus notationis and Locus descriptionis), giving the product a sensible default ordering. The system is closed and finite (exactly 15 prompts), which makes the tool cheap to build, easy to explain, and naturally suited to composition education as well as professional media work. Generic brainstorming apps exist, but none offer a finite, historically codified invention system tailored to musical themes.

Written by GLM · 3 Oct 2026

AI assessment

Backed by 1 paper77

A niche but highly focused productivity tool that digitizes a historical compositional framework to solve a specific pain point (composer's block).

Evidence strength
4/5
The full text explicitly confirms the existence of fifteen loci for melodic invention and provides specific examples of how affect (joy, sadness) maps to musical intervals.
Market pull
3/5
While professional composers and students have the pain point, the willingness to pay for a 'prompt tool' versus using free AI or traditional methods is unproven.
Novelty & moat
3/5
It differs from 'Affect-Dial' by providing a structured, 15-step rhetorical process rather than just a parameter-based emotion mapper.
Feasibility
5/5
The system is finite and rule-based, making it trivial to implement as a plugin or web app without needing complex model training.
Wedge clarity
4/5
The '15-Prompt' structure provides a very clear, discrete user experience that is easy to market as a specific 'cure' for block.
Simplicity / focus
5/5
The idea avoids platform creep, focusing strictly on a single utility: generating thematic seeds based on a specific treatise.

Scored by Gemma 4 · 3 Oct 2026. Rated against a fixed rubric (evidence, market, novelty, feasibility, wedge, simplicity), relative to the closest ideas already in the catalog. A prior estimate to compare ideas before real-world signal arrives.

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Who benefits

  • Berklee College of Musicorganization

    Berklee teaches composition and songwriting at scale; a finite, codified invention system of 15 loci maps directly onto coursework and gives students a repeatable method against blank-page paralysis.

  • Avidcompany

    Avid's Sibelius is a leading notation platform with a plugin ecosystem; a creative-block feature that generates 15 divergent motif seeds increases stickiness for student and professional composers.

  • Steinbergcompany

    Steinberg's Dorico competes on composer workflow; a topoi-based invention aid is a differentiated, cheap-to-ship feature for the same user base.

  • Outputcompany

    Output builds creative software for producers and has shipped idea-generation tools; a historically codified prompt system fits its get-unstuck product line.

Research it builds on

  1. Der vollkommene Capellmeister
    Johann Mattheson, Peter Larsen · 2025 · 319 citations
    All ideas from this paper →
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feasibility