A set of scripts for inspecting and controlling the Steam client through its built-in Chromium debugging connection. It can work with Steam's visible Game Mode screens and internal browser contexts.

Use it to list Steam windows, inspect page content, run JavaScript probes, navigate, click controls, send key presses, take screenshots, and read console errors.

It gives developers a way to check Steam UI behavior and diagnose problems remotely without manually operating every screen.

steam-cdp — 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 steam-cdp

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/steam-cdp/github.svg)](https://agentmods.dev/skills/jinzhongjia/decky-music/steam-cdp)

Your own site

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

Per session 82 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,433 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. Third-party audits

NVIDIA SkillSpector warn 7 Sept 2026

SkillSpector: 2 findings, up to high

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 →

high Memory Poisoning · line 89
Skill manipulates agent memory, state, or stored context. Memory corruption can alter personality, override safety rules, or cause unpredictable behavior.

Fix: Protect agent memory and state from modification by untrusted content. Use read-only memory for critical instructions and validate all state changes.
medium Memory Poisoning · line 84
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	$0.00082	$0.01433
Opus 5.5	$0.00033	$0.00573
Sonnet 5.5	$0.00016	$0.00287
Haiku 4.5	$0.00008	$0.00143

Measured 19d ago against content hash 6af81cca8eb6, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

steam-cdp 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 19d ago.

The scan reads SKILL.md. This mod also ships 9 executable files (scripts/cdp-console.mjs, scripts/cdp-key.mjs, scripts/cdp-lib.mjs, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

.agents/skills/steam-cdp/SKILL.md · 111 lines

How it starts

The opening of the file, as written. The whole thing — 111 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Steam CDP Automation

Steam's embedded Chromium (CEF) exposes remote debugging on localhost:8080 on the device (enabled by default in Decky environments; desktop Steam needs -cef-enable-debugging). Everything here is read-only diagnosis and test driving — never ship CDP tricks inside a plugin. The bundled scripts live in scripts/ next to this file and are dependency-free (Node ≥ 21 for global fetch/WebSocket).

Setup (once per machine session)

ssh -N -L 8080:localhost:8080 deck@<ip> &     # tunnel; survives plugin_loader restarts
node scripts/cdp.mjs targets                  # list targets, sanity-check the tunnel

Targets

Alias	Target	Use for
`bp`	gamepad-UI main window ("Steam Big Picture Mode" / localized)	the visible screen: screenshots, DOM clicks, key input
`qam`	QuickAccess	Quick Access Menu overlay
`mainmenu`	MainMenu	left Steam main menu overlay
`shared` / `sjc`	SharedJSContext	main JS context (no pixels) — webpack/module probing

Script inventory

node scripts/cdp.mjs targets                      # list targets with aliases
node scripts/cdp.mjs <target> <probe.js>          # Runtime.evaluate a JS file, print its return value
node scripts/cdp-nav.mjs /your-route              # navigate the gamepad UI to a route
node scripts/cdp-shot.mjs bp /tmp/ui.png          # screenshot a target to PNG
node scripts/cdp-key.mjs bp ArrowDown Enter       # dispatch keyDown/keyUp pairs
node scripts/cdp-console.mjs shared 30            # stream console warnings/errors for N seconds
node scripts/cdp.mjs mainmenu scripts/probe-mainmenu.js    # example probe: menu patch anchors

cdp-lib.mjs is the shared helper (target resolution, sessions, evaluate, screenshot, keys) — import it to build new drivers.

Writing probes

A probe is an IIFE evaluated in the target page. Return a JSON-serializable value instead of printing from inside the page. Reuse the bundled probes before writing another React-fiber walk.

Read the full file on GitHub · 111 lines

Files

What ships with it

9 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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.

19d ago Changed · +5 lines 6af81cca8eb6
2mo ago First seen · 106 lines · 82 tokens per session scan A 1aea64ad4b42

Subscribe to this mod's changes

steam-cdp is a skill published in the GitHub repository jinzhongjia/decky-music (125 stars, last pushed 2d ago), licensed MIT. It adds 82 tokens to every session and 1,433 once invoked, about $0.0003 per session on Opus 5.5. 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 2026-08-30.

Browser automation decky-plugin netease netease-music qqmusic steamdeck

steam-cdp next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
steam-cdpjinzhongjia/decky-music	Skill	125	2d ago	MIT	A	82	Claude Code, Codex
interactive-loginyc-software/qm	Skill	16k	yesterday	MIT	A	46	Claude Code, Codex
pinchtab-mcppinchtab/pinchtab	Skill	11k	10d ago	MIT	A	52	Claude Code, Codex
azure-messaging-webpubsub-javamicrosoft/skills	Skill	3.2k	yesterday	MIT	A	43	Claude Code
cua-driverdavidondrej/skills	Skill	4.3k	3d ago	MIT	A	68	Claude Code, Codex
open-design-browsercompozy/compozy	Skill	2.8k	yesterday	MIT	A	56	Claude Code, Codex
southwestborski/travel-hacking-toolkit	Skill	895	yesterday	MIT	A	40	Claude Code