procedural-audio

procedural-audio is a skill for Claude Code, Codex from jxoesneon/Ciel. It costs 38 tokens per session (1,558 once invoked), scanned A, original, Apache-2.0.

A system for creating sound effects, music, and spatial audio entirely from code and mathematical signal processing, without stored audio samples.

In plain words
What is it for?
It is for generating ambient soundscapes, adaptive music, interface sounds, physical impacts, and audio that changes with distance or obstruction.
Why use it?
It lets interactive software produce changing audio based on scenes, physics, and events without depending on a library of fixed recordings.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit It is for generating ambient soundscapes, adaptive music, interface sounds, physical impacts, and audio that changes with distance or obstruction.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/jxoesneon/ciel/procedural-audio
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add jxoesneon/Ciel --skill procedural-audio
Clone the repo
git clone --depth 1 https://github.com/jxoesneon/Ciel

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for procedural-audio

README.md
[![agentmods](https://agentmods.dev/badge/skills/jxoesneon/ciel/procedural-audio/github.svg)](https://agentmods.dev/skills/jxoesneon/ciel/procedural-audio)
Your own site
<a href="https://agentmods.dev/skills/jxoesneon/ciel/procedural-audio"><img src="https://agentmods.dev/badge/skills/jxoesneon/ciel/procedural-audio/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for procedural-audio

Your own site · 80×15
<a href="https://agentmods.dev/skills/jxoesneon/ciel/procedural-audio"><img src="https://agentmods.dev/badge/skills/jxoesneon/ciel/procedural-audio.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 38 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,558 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00038 $0.01558
Opus 5 $0.00019 $0.00779
Sonnet 5 $0.00008 $0.00312
Haiku 4.5 $0.00004 $0.00156

Measured 5d ago against content hash 4a9716599004, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

procedural-audio scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/procedural-audio/SKILL.md · 72 lines

How it starts

The opening of the file, as written. The whole thing — 72 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CIEL ADAPTATION: Procedural Audio & Autonomous Audiography

Synthesizes studio-grade sound effects, adaptive music, and spatial acoustic environments purely from code and mathematical DSP. Given a minimalist prompt like "create the audio for this screen", autonomously extracts the scene's visual palette, node hierarchy, physics properties, and narrative context to emit production-ready, zero-dependency procedural audio. Writes audio files to disk (declared fs side effect).

4-Layer Sound Architecture

  • Layer 1 — Ambient Soundscape: Sub-bass fundamentals (35–110 Hz), continuous room tones/wind, multi-band colored noise.
  • Layer 2 — Generative Music: Neo-Riemannian Tonnetz & modal progressions, 5-tier adaptive stems modulated by Dynamic Tension Index (DTI), 1/f Voss-McCartney pink-noise melody + Euclidean grooves.
  • Layer 3 — Interactive Foley & SFX: Kinetic physics impacts (E=½mv²), dual-sine/chirp UI clicks, physical modeling (Karplus-Strong).
  • Layer 4 — Spatial Acoustics: ITD/ILD/pinna-notch binaural spatializer, distance attenuation (1/r) + ISO 9613-1 air absorption, raycast occlusion filter (20 kHz → 350 Hz).

One-Shot Audiographer Protocol

  1. Scene ingestion: Scan .tscn/DOM/Unity YAML for BaseButton (UI), RigidBody2D/3D + CollisionShape (impacts), TileMapLayer (footsteps), GPUParticles (weather), Camera/AudioListener3D.
  2. Synesthetic mapping: Compute Valence-Arousal-Dominance (VAD) vector; extract dominant hex codes → map to mode/key, synthesis model, filter cutoff/resonance, spatial effects.
  3. DTI derivation: Real-time tension DTI ∈ [0,1] from HP ratio, threat count, target distance, time remaining.
  4. Code emission: Emit complete zero-dependency engine script (Godot AudioStreamGenerator, Web Audio AudioWorklet, or Python baker).
  5. Signal binding: Connect pressed/mouse_entered/body_entered directly to synthesis functions; hot reload.

Core DSP Synthesis Patterns

  • Karplus-Strong: Delay D = f_s/f_0 − 0.5; loop filter with decay 10^(−3/(f_0·T_60)).
  • Modal synthesis: Per-mode damped sinusoid y_k[n] = 2e^(−αT)cos(ω_d T)y_k[n−1] − e^(−2αT)y_k[n−2] + a_k sin(ω_d T)x[n]. Material mode ratios: cast iron [1,1.414,2.14,2.76,3.82,5.12], hardwood [1,1.84,2.72,3.91], glass [1,2.32,4.15,6.47,9.28], granite [1,1.29,1.74,2.21,2.94].
  • PolyBLEP anti-aliased oscillators: Apply residual correction R(t,dt) at phase discontinuities for saw/square.
  • Moog Ladder 4-pole TPT: g = tan(πf_c/f_s), G = g/(1+g), tanh feedback for self-oscillation.
  • Minnaert bubble: f_0 ≈ 3.0/R (meters); decaying chirp for raindrops/liquid.

Read the full file on GitHub · 72 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 5d ago First seen · 72 lines · 38 tokens per session scan A 4a9716599004

Subscribe to this mod's changes

procedural-audio is a skill published in the GitHub repository jxoesneon/Ciel (1 stars, last pushed yesterday), licensed Apache-2.0. It adds 38 tokens to every session and 1,558 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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