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Develop Userscripts · xixu-me | DecimalAI

codingby xixu-me

Develop Userscripts

develop-userscripts

Source xixu-me/skills ↗License MIT

Use when building, debugging, packaging, or publishing browser userscripts for Tampermonkey or ScriptCat, including GM APIs, metadata blocks, permission issues, @match/@grant/@connect setup, ScriptCat background or scheduled scripts, UserConfig blocks, or subscription workflows.

SkillScore32Maintained

Automatic

Coding pack

Last verified 7/23/2026

What it changes

Passed 7 of 22 test cases with the skill, and 1 of 22 without it.

Without skill5%

With skill32%

6 fixed1 passed either way15 still failing0 broke

Pass-rate lift: +27 pp
Tokens: +19%
Agent turns: 0%
Response time: -32%

Model gemini-3.6-flashMeasured 7/23/2026v17 of 22 cases passed with skill

Tokens, turns and time describe resource use, not a dollar price.

Use this skill

Save it into your project's skills folder. Claude Code picks it up in its next session.

curl -fsSL --create-dirs -o .claude/skills/develop-userscripts/SKILL.md https://app.decimal.ai/s/develop-userscripts/SKILL.md

Want it pinned and updatable? pip install "decimalai>=0.15", then decimalai skills add develop-userscripts, and start Claude Code with claude --plugin-dir "$(git rev-parse --show-toplevel)/.agents"

1 · One-time — install the CLI (docs ↗)

pip install "decimalai>=0.15"

2 · Get the skill — writes .agents/skills/develop-userscripts/ and pins it in .decimal/skills.lock

decimalai skills add develop-userscripts

No CLI? Get the same file — curl · raw file

curl -fsSL --create-dirs -o .claude/skills/develop-userscripts/SKILL.md https://app.decimal.ai/s/develop-userscripts/SKILL.md

Raw file: /s/develop-userscripts/SKILL.md ↗ · machine-readable summary at /s/develop-userscripts.json ↗

Safety checks: 3 of 3 passed

Code scan CleanIntent PassedContent Clean

What's inside

The instructions your model reads when the skill loads.

SKILL.md79 lines3 files

Userscript work usually breaks at the runtime and metadata boundary, not in the page logic. Choose the runtime first, declare the minimum permissions up front, then debug in the environment where the script actually runs.

When to Use

Use this skill for:

writing or fixing a Tampermonkey or ScriptCat userscript
debugging injection timing, missing permissions, CSP workarounds, update checks, or GM_* behavior
deciding between a portable foreground script and ScriptCat-only @background or @crontab
adding config UI with ==UserConfig==
packaging a ScriptCat ==UserSubscribe== bundle or preparing a CloudCat-compatible script

Do not use this skill for full browser extension development or general browser automation outside userscript managers.

Runtime Selection

digraph userscript_runtime {
    "Need page DOM or page context?" [shape=diamond];
    "Need persistent or scheduled work?" [shape=diamond];
    "Need to install many scripts as one package?" [shape=diamond];
    "Portable foreground script" [shape=box];
    "ScriptCat background or crontab script" [shape=box];
    "ScriptCat subscription package" [shape=box];

    "Need page DOM or page context?" -> "Portable foreground script" [label="yes"];
    "Need page DOM or page context?" -> "Need persistent or scheduled work?" [label="no"];
    "Need persistent or scheduled work?" -> "ScriptCat background or crontab script" [label="yes"];
    "Need persistent or scheduled work?" -> "Need to install many scripts as one package?" [label="no"];
    "Need to install many scripts as one package?" -> "ScriptCat subscription package" [label="yes"];
    "Need to install many scripts as one package?" -> "Portable foreground script" [label="no"];
}

Preflight

Confirm the manager and browser. On Manifest V3 browsers, ScriptCat may require Allow User Scripts or browser developer mode before scripts run.
Decide page script versus background script before writing code. ScriptCat background scripts cannot touch the DOM.
Start with metadata, not implementation: @match, @grant, @connect, @run-at, and any update URLs.
Prefer portable ==UserScript== patterns for ordinary page scripts. Only switch to ScriptCat-only headers when the requested behavior actually needs them.

Track record

Benchmark

7 / 22

test cases passed, vs 1 / 22 without

Adoption

Users: 0
Times used: 0

Safety and source details

SkillSafety

✓ 3 of 3 passed

Code scan15 of 15 checks clean

0 critical · 0 warning · 0 info — scanner v4 — 7/30/2026

View 15 scanner checks

live_secretremote_code_executionreverse_shelldata_exfiltrationssrf_metadataagent_snoopinganti_refusaldestructive_commandsobfuscated_unicodeunicode_homoglyphopaque_blobsuspicious_urltool_overreachtrigger_abuseprompt_injection_phrasing

IntentSafe

LLM judge · does the skill do what it claims

ContentClean

LLM judge · policy & harmful-content review

Source

Imported

xixu-me / skills

skills/develop-userscripts/SKILL.md

View on GitHub ↗

License MITImported 8/1/2026Version v1Bundled 2 files

More skills from the same source and nearby in the registry, with their headline benchmark lift.