Openfasttrace Reverse Specs
itsallcode/openfasttrace
Reverse-engineer missing or incomplete OpenFastTrace system requirements and arc42-style design documentation from a project's user guide, existing documentation, tests, and code.
Decompile Java applications (JAR/WAR/APK/class) — extract archives, detect obfuscators, decompile bytecode to source, analyse license logic and secrets.
Install Java Decompiler
$ npx skills add ptn1411/skill --skill java-decompiler -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install ptn1411/skill java-decompiler --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/ptn1411/skill.git skills-src && mkdir -p .claude/skills && cp -r skills-src/java-decompiler .claude/skills/java-decompiler && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "java-decompiler" agent skill from https://github.com/ptn1411/skill/tree/main/java-decompiler into .claude/skills/java-decompiler/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "java-decompiler", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/ptn1411/skill/tree/main/java-decompilerType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add ptn1411/skill --skill java-decompiler -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install ptn1411/skill java-decompiler --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/ptn1411/skill.git skills-src && mkdir -p .agents/skills && cp -r skills-src/java-decompiler .agents/skills/java-decompiler && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "java-decompiler" agent skill from https://github.com/ptn1411/skill/tree/main/java-decompiler into .agents/skills/java-decompiler/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "java-decompiler", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add ptn1411/skill --skill java-decompiler -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install ptn1411/skill java-decompiler --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/ptn1411/skill.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/java-decompiler .cursor/skills/java-decompiler && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "java-decompiler" agent skill from https://github.com/ptn1411/skill/tree/main/java-decompiler into .cursor/skills/java-decompiler/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "java-decompiler", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/ptn1411/skill.git --path java-decompiler--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add ptn1411/skill --skill java-decompiler -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install ptn1411/skill java-decompiler --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/ptn1411/skill.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/java-decompiler .gemini/skills/java-decompiler && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "java-decompiler" agent skill from https://github.com/ptn1411/skill/tree/main/java-decompiler into .gemini/skills/java-decompiler/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "java-decompiler", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install ptn1411/skill java-decompilerInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add ptn1411/skill --skill java-decompiler -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/ptn1411/skill.git skills-src && mkdir -p .github/skills && cp -r skills-src/java-decompiler .github/skills/java-decompiler && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "java-decompiler" agent skill from https://github.com/ptn1411/skill/tree/main/java-decompiler into .github/skills/java-decompiler/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "java-decompiler", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add ptn1411/skill --skill java-decompiler -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install ptn1411/skill java-decompiler --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/ptn1411/skill.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/java-decompiler .opencode/skills/java-decompiler && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "java-decompiler" agent skill from https://github.com/ptn1411/skill/tree/main/java-decompiler into .opencode/skills/java-decompiler/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "java-decompiler", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
java-decompiler- GitHub stars
- 219
- Token cost
- ~788 tokens
- SKILL.md length
- 186 words
- Files
- 5 (incl. scripts, references)
- Skills in repo
- 22
- Repo updated
- First seen
- Licence
- None found
At a glance
Decompile Java applications (JAR/WAR/APK/class) — extract archives, detect obfuscators, decompile bytecode to source, analyse license logic and secrets.
- Tasks that involve Reverse engineering and malware
- SKILL.md covers Purpose, Workflow, Usage and Decompiler Priority, plus 3 more sections
- Runs Python scripts from its folder; calls python and pip
What it does
Java Decompiler is an agent skill from ptn1411/skill. Decompile Java applications (JAR/WAR/APK/class) — extract archives, detect obfuscators, decompile bytecode to source, analyse license logic and secrets.
Its SKILL.md is about 790 tokens, which your agent loads only when the skill is triggered. The skill folder holds 7 other files, including scripts and reference files (for example `references/java_re_patterns.md`, `scripts/analyze_java.py` and `scripts/decompile_java.py`).
It sits in Security, covering Reverse engineering and malware. It works with Java. The repository describes itself as: Bộ công cụ và tập hợp skill hỗ trợ phân tích phần mềm, khôi phục cấu trúc nguồn ở mức cần thiết, rà soát bảo mật, kiểm tra phụ thuộc và xây dựng kế hoạch khắc phục cho các hệ…
When your agent uses it
- Tasks that involve Reverse engineering and malware
Example prompts
- “/java-decompiler”
Requirements
- Python 3
- Pre-approved tools (allowed-tools): Read, Write, Edit, Glob, Grep, Bash
What it can do on your machine
Read from SKILL.md and the folder at commit ce2b65e. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves these tools, so the agent can use them without asking each time:
ReadWriteEditGlobGrepBash
From allowed-tools in the SKILL.md frontmatter.
Runs code
Ships 2 files in scripts/ (Python), which the agent can run.
Shell commands in SKILL.md call:
pythonpip
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use pip, which can reach the network depending on how they are called.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Java Decompiler loads about 788 tokens when it runs, and up to ~2.1k if it reads all its reference files. Until then it costs about 42 tokens; SKILL.md has 186 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check: notes
The automated check noted patterns worth knowing about, such as sudo or a known installer.
- NotePre-approves every shell command (allowed-tools: Bash)SKILL.md
allowed-tools: Read, Write, Edit, Glob, Grep, Bash
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.
SKILL.md
Without a licence we can't republish the file, so here is its outline and opening line. It has 186 words (~788 tokens).
“Java bytecode (.class) retains nearly all source-level information, making decompilation highly effective. This skill extracts, decompiles, and analyses Java applications across all packaging formats: JAR, WAR, EAR, APK, and raw class files.”
- name
- java-decompiler
- allowed-tools
- Read, Write, Edit, Glob, Grep, Bash
Files
SKILL.md and 4 other files (scripts, references) in java-decompiler of ptn1411/skill.
- SKILL.md
- references/java_re_patterns.md
- scripts/analyze_java.py
- scripts/decompile_java.py
- tests/test_decompile_java.py
Open the folder on GitHubat commit ce2b65e
Compare with similar skills
Java Decompiler next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Java Decompiler this skillptn1411/skill | 219 | — | ~788 | Automated safety check: Notes | None | |
| Openfasttrace Reverse Specsitsallcode/openfasttrace | 198 | — | ~2.9k | Automated safety check: Pass | GPL-3.0 | |
| APK Static Analysisdslsdzc/rev-skills | 117 | — | ~2k | Automated safety check: Pass | Apache-2.0 | |
| Code Audit3stoneBrother/code-audit | 893 | 1 repos | ~2.7k | Automated safety check: Pass | None | |
| Webhome Extension Builderwebhtv/webhtv | 1.7k | — | ~2.8k | Automated safety check: Pass | GPL-3.0 | |
| CodeQL Security Scantrailofbits/skills | 7.4k | — | ~4.6k | Automated safety check: Notes | CC-BY-SA-4.0 |
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Related
Works with
Categories
Questions about Java Decompiler
What does Java Decompiler do?
Decompile Java applications (JAR/WAR/APK/class) — extract archives, detect obfuscators, decompile bytecode to source, analyse license logic and secrets. Java Decompiler is an agent skill from ptn1411/skill. Decompile Java applications (JAR/WAR/APK/class) — extract archives, detect obfuscators, decompile bytecode to source, analyse license logic and secrets.
When should I use Java Decompiler?
Java Decompiler fits situations like: tasks that involve Reverse engineering and malware.
How do I install Java Decompiler in Claude Code?
Run `npx skills add ptn1411/skill --skill java-decompiler -a claude-code`. Or copy the skill folder (java-decompiler in ptn1411/skill) into .claude/skills/java-decompiler in your project. Claude Code loads it when a task matches its description.
How do I install Java Decompiler in Codex?
Run `npx skills add ptn1411/skill --skill java-decompiler -a codex`. Or copy the skill folder (java-decompiler in ptn1411/skill) into .agents/skills/java-decompiler in your project. Codex loads it when a task matches its description.
Can I use Java Decompiler in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add ptn1411/skill --skill java-decompiler -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/java-decompiler, .gemini/skills/java-decompiler, .github/skills/java-decompiler and .opencode/skills/java-decompiler in your project.
What does Java Decompiler need to run?
Going by SKILL.md and its folder, Java Decompiler needs Python for the scripts in its folder and the command-line tools its instructions call (python and pip). Our summary lists: Python 3. Its frontmatter pre-approves these tools: Read, Write, Edit, Glob, Grep, Bash.
Does Java Decompiler access the network?
SKILL.md contains no URLs. Its commands use pip, which can reach the network depending on how they are called. This is read from the text; nothing was executed.
Is Java Decompiler safe to install?
Our automated static check of SKILL.md found notes only (pre-approves every shell command (allowed-tools: bash)), nothing it rates as a warning. It is not a guarantee. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.
What licence does Java Decompiler use?
No licence was found for Java Decompiler or its repository. Without one, default copyright applies: ask the author before reusing or redistributing it.
How many tokens does Java Decompiler use?
About 788 tokens (SKILL.md is roughly 3.2k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 1.3k tokens, read only when the agent opens those files.
What are the alternatives to Java Decompiler?
Skills that share tags, products or a category with Java Decompiler: Openfasttrace Reverse Specs (itsallcode/openfasttrace, 198 stars), APK Static Analysis (dslsdzc/rev-skills, 117 stars), Code Audit (3stoneBrother/code-audit, 893 stars) and Webhome Extension Builder (webhtv/webhtv, 1.7k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Java Decompiler?
ptn1411 (a GitHub user) maintains it in ptn1411/skill, which has 219 GitHub stars. The repository holds 22 skills in this directory. The repository was last updated on September 22, 2026.
Source: ptn1411/skill on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.