A development workflow for Decky Loader plugins, which add features to the Steam interface on Steam Deck. It covers writing the plugin, putting it on a real device, inspecting logs, controlling the running interface, and checking the result.

Use it to build, install, reload, debug, and verify Decky plugins, including their Python backends and Steam UI frontends.

It brings coding, deployment, debugging, and on-device verification into one workflow, so problems can be tested on the actual Steam Deck environment.

decky-dev — Skill for Claude Code and Codex by jinzhongjia/decky-music

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 jinzhongjia/decky-music --skill decky-dev

Clone the repo

git clone --depth 1 https://github.com/jinzhongjia/decky-music

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/jinzhongjia/decky-music/decky-dev/github.svg)](https://agentmods.dev/skills/jinzhongjia/decky-music/decky-dev)

Your own site

<a href="https://agentmods.dev/skills/jinzhongjia/decky-music/decky-dev"><img src="https://agentmods.dev/badge/skills/jinzhongjia/decky-music/decky-dev/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/jinzhongjia/decky-music/decky-dev"><img src="https://agentmods.dev/badge/skills/jinzhongjia/decky-music/decky-dev.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 73 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,327 The whole file, excluding the scripts and references it only reads on demand.

Security scan B 2 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

NVIDIA SkillSpector warn 7 Sept 2026

SkillSpector: 3 findings, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

medium Privilege Escalation · line 16
Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.

Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
medium Rogue Agent · line 60
Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.

Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
medium Memory Poisoning · line 78
Skill attempts to fill the context window with filler content, displacing legitimate instructions and safety constraints. This can degrade agent performance or bypass safety boundaries.

Fix: Implement context-window management that detects and rejects padding or stuffing attempts. Prioritize system instructions over user-injected content.

How audits are shown

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.

Model	Per session	Once invoked
Fable 5.1	$0.00073	$0.01327
Opus 5.5	$0.00029	$0.00531
Sonnet 5.5	$0.00015	$0.00265
Haiku 4.5	$0.00007	$0.00133

Measured 2mo ago against content hash 1df49ff93029, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade B, and why

decky-dev scanned grade B with 2 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 2mo 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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

`sudo systemctl restart plugin_loader`.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -s localhost:8080/json | jq '.[].title'

.agents/skills/decky-dev/SKILL.md · 105 lines

How it starts

The opening of the file, as written. The whole thing — 105 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Decky Plugin Development & Debugging (generic)

Everything here is generic Decky knowledge. Repo-specific policy (deploy consent, log content rules, commit rules) lives in the project's AGENTS.md and always wins.

Target environment

SteamOS in a gamescope session, user deck, reachable over SSH (DECK_HOST=deck@<ip> — no default; a hardcoded one goes stale and silently targets the wrong host).
Decky Loader = plugin_loader systemd unit (root). Restart to reload plugins: sudo systemctl restart plugin_loader.
Homebrew tree: ~/homebrew/{plugins,logs,settings,data}/<plugin name> — directory names use plugin.json's name field, spaces included.

Plugin anatomy

main.py Plugin class: async methods are the RPC surface for the frontend (@decky/api callable); decky.emit pushes events to the UI. Backend runs in Decky's frozen CPython — stdlib only, compiled extensions will break on Decky upgrades.
py_modules/ is the only extra dir added to sys.path and packaged by the CLI.
Frontend ships as dist/index.js (built from @decky/api + @decky/ui).
package.json remote_binary: assets downloaded at install time into bin/<name> — saved verbatim, never unpacked. Archives (e.g. Nuitka standalone tar.gz) must be self-extracted by plugin code on first use. Pin URLs to a release tag: releases/latest/... 404s for prereleases.
Installed permissions: plugin root dir is root:root (read-only for deck), but bin/ and py_modules/ are deck:deck (writable) — the remote_binary downloader itself writes bin/.

Deploy loop (sideload)

Sideload = build → rsync the plugin subset → restart plugin_loader. Keep it in a repo script (this repo: scripts/deploy.sh; target is required: DECK_HOST=deck@ip). Two rules that bite:

Deploy scripts copy prebuilt artifacts, they don't build. Rebuild changed binaries first, or you ship stale ones.
A sideload dev_mode marker file (touched by the deploy script, absent from release zips) is a clean way to switch log verbosity; release zips must not contain it.

Read the full file on GitHub · 105 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.

2mo ago First seen · 105 lines · 73 tokens per session scan B 1df49ff93029

Subscribe to this mod's changes

decky-dev is a skill published in the GitHub repository jinzhongjia/decky-music (125 stars, last pushed 2d ago), licensed MIT. It adds 73 tokens to every session and 1,327 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it B with 2 findings (asks for root, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

DevOps and cloud Game development decky-plugin netease netease-music qqmusic steamdeck

decky-dev next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
decky-devjinzhongjia/decky-music	Skill	125	2d ago	MIT	B	73	Claude Code, Codex
playtest-reportDonchitos/Claude-Code-Game-Studios	Skill	36k	18d ago	MIT	A	20	Claude Code
godot-signals-groupsgamedev-skills/awesome-gamedev-agent-skills	Skill	6.9k	9d ago	Apache-2.0	A	95	Claude Code
scenario-unreal-gameplayscenario-labs/skills	Skill	3.2k	yesterday	MIT	A	121	Claude Code
motionOpenDCAI/GameFactory-3A	Skill	1.0k	8d ago	Apache-2.0	A	0	Claude Code, Codex
unity-addressablesBesty0728/Unity-Skills	Skill	1.9k	yesterday	MIT	A	25	Claude Code, Codex
unity-manual-componentBesty0728/Unity-Skills	Skill	1.9k	yesterday	MIT	A	36	Claude Code, Codex

decky-dev