Crossbind
crossbind/crossbind
A skill your agent uses when a user wants to call C++ or Rust from JavaScript or TypeScript; add a native library such as GDAL, SQLite, OpenSSL, GEOS or PROJ to a browser, Node.js, Cloudflare Worker…
React Native JSI (JavaScript Interface) — C++ API for interacting with the JS runtime.
Install Jsi
$ npx skills add software-mansion-labs/skills --skill jsi -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install software-mansion-labs/skills jsi --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/software-mansion-labs/skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/react-native-best-practices/references/jsi .claude/skills/jsi && 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 "jsi" agent skill from https://github.com/software-mansion-labs/skills/tree/main/skills/react-native-best-practices/references/jsi into .claude/skills/jsi/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "jsi", 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/software-mansion-labs/skills/tree/main/skills/react-native-best-practices/references/jsiType 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 software-mansion-labs/skills --skill jsi -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install software-mansion-labs/skills jsi --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/software-mansion-labs/skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/react-native-best-practices/references/jsi .agents/skills/jsi && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "jsi" agent skill from https://github.com/software-mansion-labs/skills/tree/main/skills/react-native-best-practices/references/jsi into .agents/skills/jsi/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "jsi", 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 software-mansion-labs/skills --skill jsi -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install software-mansion-labs/skills jsi --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/software-mansion-labs/skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/react-native-best-practices/references/jsi .cursor/skills/jsi && 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 "jsi" agent skill from https://github.com/software-mansion-labs/skills/tree/main/skills/react-native-best-practices/references/jsi into .cursor/skills/jsi/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "jsi", 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/software-mansion-labs/skills.git --path skills/react-native-best-practices/references/jsi--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 software-mansion-labs/skills --skill jsi -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install software-mansion-labs/skills jsi --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/software-mansion-labs/skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/react-native-best-practices/references/jsi .gemini/skills/jsi && 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 "jsi" agent skill from https://github.com/software-mansion-labs/skills/tree/main/skills/react-native-best-practices/references/jsi into .gemini/skills/jsi/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "jsi", 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 software-mansion-labs/skills jsiInstalls 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 software-mansion-labs/skills --skill jsi -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/software-mansion-labs/skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/react-native-best-practices/references/jsi .github/skills/jsi && 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 "jsi" agent skill from https://github.com/software-mansion-labs/skills/tree/main/skills/react-native-best-practices/references/jsi into .github/skills/jsi/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "jsi", 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 software-mansion-labs/skills --skill jsi -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install software-mansion-labs/skills jsi --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/software-mansion-labs/skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/react-native-best-practices/references/jsi .opencode/skills/jsi && 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 "jsi" agent skill from https://github.com/software-mansion-labs/skills/tree/main/skills/react-native-best-practices/references/jsi into .opencode/skills/jsi/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "jsi", 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
jsi- GitHub stars
- 291
- Token cost
- ~904 tokens
- SKILL.md length
- 269 words
- Files
- 11
- Skills in repo
- 20
- Repo updated
- First seen
- Licence
- None found
At a glance
React Native JSI (JavaScript Interface) — C++ API for interacting with the JS runtime.
- The user asks about
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
- Writes C++ code that touches JSI types
- Patterns: jsi::Runtime
What it does
Jsi is an agent skill from software-mansion-labs/skills. React Native JSI (JavaScript Interface) — C++ API for interacting with the JS runtime. Use whenever the user asks about or writes C++ code that touches JSI types or patterns: jsi::Runtime, jsi::Value, jsi::Object, jsi::Function, jsi::Array, jsi::ArrayBuffer, jsi::String, jsi::Symbol, jsi::BigInt, jsi::PropNameID, jsi::HostObject, jsi::HostFunction, jsi::NativeState, jsi::WeakObject, jsi::Scope, JSIException, JSINativeException, JSError, HostFunctionType, createFromHostFunction, getHostObject, setNativeState…
Its SKILL.md is about 900 tokens, which your agent loads only when the skill is triggered. The skill folder holds 10 other files (for example `calling-js-and-async.md`, `casting-and-serialization.md` and `core-types.md`).
It sits in Mobile, covering Cross-platform mobile apps. It works with C++, React Native and JavaScript. The repository describes itself as: Software Mansion's set of skills for AI-assisted React Native development.
When your agent uses it
- The user asks about
- Writes C++ code that touches JSI types
- Patterns: jsi::Runtime
- Jsi::ArrayBuffer
Example prompts
- “/jsi”
What it can do on your machine
Read from SKILL.md and the folder at commit e3f00cd. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
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
Jsi loads about 904 tokens when it runs. Until then it costs about 247 tokens; SKILL.md has 269 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 passed
The automated check found no risky patterns in SKILL.md.
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); files beside SKILL.md are not scanned.
SKILL.md
Without a licence we can't republish the file, so here is its outline and opening line. It has 269 words (~904 tokens).
“The JavaScript Interface (JSI) is a C++ API that lets native code interact directly with the JavaScript engine — reading and writing JS values, calling JS functions, and exposing C++ objects to JS — without going through the old async…”
- name
- jsi
Files
SKILL.md and 10 other files in skills/react-native-best-practices/references/jsi of software-mansion-labs/skills.
- SKILL.md
- calling-js-and-async.md
- casting-and-serialization.md
- core-types.md
- cpp-memory-patterns.md
- debugging-and-pitfalls.md
- module-approaches.md
- overview.md
- performance.md
- setup-and-templates.md
- threading-safety.md
Open the folder on GitHubat commit e3f00cd
Compare with similar skills
Jsi 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 |
|---|---|---|---|---|---|---|
| Jsi this skillsoftware-mansion-labs/skills | 291 | — | ~904 | Automated safety check: Pass | None | |
| Crossbindcrossbind/crossbind | 148 | — | ~1.1k | Automated safety check: Pass | MIT | |
| Agent Cdpgronxb/codex-relay | 680 | — | ~956 | Automated safety check: Pass | Apache-2.0 | |
| Argent Metro Debuggerbbplayer-app/BBPlayer | 1.2k | — | ~3.4k | Automated safety check: Pass | MIT | |
| Multithreadingkingstinct/react-native-healthkit | 716 | 1 repos | ~1.1k | Automated safety check: Pass | MIT | |
| Diagnosing Stacktrace SymbolicationPostHog/posthog | 40k | — | ~2.2k | Automated safety check: Pass | Custom licence |
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Related
Works with
Categories
Questions about Jsi
What does Jsi do?
React Native JSI (JavaScript Interface) — C++ API for interacting with the JS runtime. Jsi is an agent skill from software-mansion-labs/skills. React Native JSI (JavaScript Interface) — C++ API for interacting with the JS runtime.
When should I use Jsi?
Jsi fits situations like: the user asks about; writes C++ code that touches JSI types; patterns: jsi::Runtime; jsi::ArrayBuffer.
How do I install Jsi in Claude Code?
Run `npx skills add software-mansion-labs/skills --skill jsi -a claude-code`. Or copy the skill folder (skills/react-native-best-practices/references/jsi in software-mansion-labs/skills) into .claude/skills/jsi in your project. Claude Code loads it when a task matches its description.
How do I install Jsi in Codex?
Run `npx skills add software-mansion-labs/skills --skill jsi -a codex`. Or copy the skill folder (skills/react-native-best-practices/references/jsi in software-mansion-labs/skills) into .agents/skills/jsi in your project. Codex loads it when a task matches its description.
Can I use Jsi 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 software-mansion-labs/skills --skill jsi -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/jsi, .gemini/skills/jsi, .github/skills/jsi and .opencode/skills/jsi in your project.
What does Jsi need to run?
SKILL.md names no scripts, command-line tools or credentials: Jsi is instructions for the agent only.
Does Jsi access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Jsi safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Jsi use?
No licence was found for Jsi or its repository. Without one, default copyright applies: ask the author before reusing or redistributing it.
How many tokens does Jsi use?
About 904 tokens (SKILL.md is roughly 3.6k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Jsi?
Skills that share tags, products or a category with Jsi: Crossbind (crossbind/crossbind, 148 stars), Agent Cdp (gronxb/codex-relay, 680 stars), Argent Metro Debugger (bbplayer-app/BBPlayer, 1.2k stars) and Multithreading (kingstinct/react-native-healthkit, 716 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Jsi?
software-mansion-labs (a GitHub organization) maintains it in software-mansion-labs/skills, which has 291 GitHub stars. The repository holds 20 skills in this directory. The repository was last updated on September 28, 2026.
Source: software-mansion-labs/skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.