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Random AI Prompt: a readable language for dynamic prompts

Designing and building DPL — a Markdown-like language for the generators — and making a new v3 catalog the default.

The most ambitious thread in Random AI Prompt’s revival is DPL, a Dynamic Prompt Language. The generators that build prompts had always been hand-written JavaScript. DPL is a Markdown-readable language so they can be authored and read by people who don’t write code — with a JavaScript escape hatch kept for the genuinely logic-heavy ones.

Why a language at all

A “dynamic prompt” assembles a prompt from optional pieces, weighted choices, and references to word lists. Expressing that in JavaScript means every generator is a small program, which is fine for a programmer and opaque to everyone else. The goal was a format where the structure of a prompt is visible at a glance.

What DPL looks like

Here’s a complete generator — the city street scene — verbatim:

---
description: A city streetview
---
Start
===
city, streetview, {city}
- {style/building}
- cityscape
- downtown

{#nature}, {#weather}, reflective street

The pieces are deliberately plain: front matter for metadata, a === heading for a section, a plain line that’s always included, - bullet lines that are optional (50% by default), {list} to pull from a word list, and {#generator} to call another generator. Probabilities and repetition read naturally too:

Start
===
- {art-movement}
- {art-technique}
- 50% repeat 0 to 3 times: {image-effect}
- {#rays}

And explicit either/or branching:

Start
===
portrait
- maybe: full body
- otherwise: head and chest, upperbody
- up-close

Logic stays in JavaScript

A core design decision is that DPL is data, not code — it has no variables or counters. Anything that genuinely needs logic delegates to a referenced JavaScript file, so the .dpl stays declarative:

---
description: A subject — animal, character, flower, instrument, creature, tree, or person
script: entity.js
---

The bridge works in both directions: DPL can call into JS, and JS can call back into DPL sections. About 90% of the catalog ended up as pure DPL; the rest keeps a thin .js sidecar.

A weighted layer tree

Underneath, v3 changes the model. The older generators built an ordered string where position carried meaning. v3 treats every file, section, and line as a layer in a tree — the user’s prompt box is the root, each building block a child — and renders by sorting each layer’s children by weight rather than by where they appear. Auto-weights start at 1000 and increment per line; an explicit [n] overrides:

Start
===
[100] wide shot, dramatic lighting   # low weight → sorts to the front
ancient forest, morning mist         # auto-weighted (1000, 1001, …)

Built in phases

To protect a working app, this shipped in phases: (1) the parser and renderer plus a test harness, with sample generators converted; (2) the entire existing catalog converted to DPL; (3) wiring DPL into the live engine and both loaders, making the new v3 catalog the default; and (4) the wrapper UI — a start/end frame applied around every prompt. The frozen v1 and v2 generations remain fully functional, addressed by a path prefix:

{#cave}        → v3 (the default)
{#v2/cave}     → the frozen v2 version
{#v1/castle}   → the frozen v1 version
{#any}         → pick one generator at random from the v3 catalog

The “full versus partial prompt” distinction that drove a lot of duplication in the old system is on its way out, which was the underlying goal all along.

References

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