How do I install the V8 Commands skill?

Run npx skillmds@latest add v8/v8-commands in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is V8 Commands safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with V8 Commands?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is V8 Commands free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published V8 Commands?

v8 (@v8) published this skill. Their other Agent Skills are listed on their SkillMD profile.

V8 Commands by v8 — Agent Skill

Name: V8 Commands
Author: v8

File contents

V8 Key Commands

Use this skill to find the correct commands for common development tasks in V8. This unifies the commands listed in workspace configuration and ensures consistent usage.

Building

V8 uses gm.py as a wrapper around GN and Ninja for building.

Mandatory GN Args & Siso Remote Execution Guardrails: Always include use_remoteexec = true in your args.gn or via gm.py flags to ensure builds utilize remote execution. Remote execution is mandatory in this environment.

Critical Guardrail (Path Strictness): The target output directory must sit exactly 2 levels deep relative to the project root (e.g., out/x64.debug or out/x64.release).

Build (Debug): tools/dev/gm.py quiet x64.debug tests
Build (Optimized Debug): tools/dev/gm.py quiet x64.optdebug tests
Build (Release): tools/dev/gm.py quiet x64.release tests
Sync DEPS Options: Use tools/dev/gm.py quiet x64.optdebug.d8 --sync to sync DEPS when switching between branches. Use the slower --sync=force option if there are still issues with broken DEPS.

Note: Always pass the quiet keyword unless told otherwise to avoid excessive output.

Debugging

Run d8 with GDB or LLDB for native code debugging.

# Example of running d8 with gdb
gdb --args out/x64.debug/d8 --my-flag my-script.js

Common Diagnostic Flags

--trace-opt: Log optimized functions.
--trace-deopt: Log when and why functions are deoptimized.
--trace-gc: Log garbage collection events.
--allow-natives-syntax: Enables calling of internal V8 functions (e.g., %OptimizeFunctionOnNextCall(f)) from JavaScript for testing purposes.
--gdbjit: Allows seeing Maglev graphs or JavaScript code in GDB backtraces. To debug issues involving code motion disable gdbjit (as it disables code motion).

A comprehensive list of all flags can be found by running out/x64.debug/d8 --help.

Testing

For detailed instructions on running tests and interpreting failures, see the dedicated test execution guidelines.

Key commands summary:

Run tests: tools/run-tests.py --progress dots --outdir=out/x64.optdebug

---name: v8-commandsdescription: Key commands for building, debugging, and testing in V8. Use when needing command syntax for gm.py, d8 flags, or run-tests.py. Do not use for environment setup.---# V8 Key CommandsUse this skill to find the correct commands for common development tasks in V8.This unifies the commands listed in workspace configuration and ensuresconsistent usage.## BuildingV8 uses `gm.py` as a wrapper around GN and Ninja for building.**Mandatory GN Args & Siso Remote Execution Guardrails**: Always include`use_remoteexec = true` in your `args.gn` or via `gm.py` flags to ensure buildsutilize remote execution. Remote execution is mandatory in this environment.**Critical Guardrail (Path Strictness)**: The target output directory must sitexactly 2 levels deep relative to the project root (e.g., `out/x64.debug` or`out/x64.release`).- **Build (Debug):** `tools/dev/gm.py quiet x64.debug tests`- **Build (Optimized Debug):** `tools/dev/gm.py quiet x64.optdebug tests`- **Build (Release):** `tools/dev/gm.py quiet x64.release tests`- **Sync DEPS Options:** Use `tools/dev/gm.py quiet x64.optdebug.d8 --sync` to sync DEPS when switching between branches. Use the slower `--sync=force` option if there are still issues with broken DEPS.*Note: Always pass the `quiet` keyword unless told otherwise to avoid excessiveoutput.*## DebuggingRun `d8` with GDB or LLDB for native code debugging.```bash# Example of running d8 with gdbgdb --args out/x64.debug/d8 --my-flag my-script.js```### Common Diagnostic Flags- `--trace-opt`: Log optimized functions.- `--trace-deopt`: Log when and why functions are deoptimized.- `--trace-gc`: Log garbage collection events.- `--allow-natives-syntax`: Enables calling of internal V8 functions (e.g., `%OptimizeFunctionOnNextCall(f)`) from JavaScript for testing purposes.- `--gdbjit`: Allows seeing Maglev graphs or JavaScript code in GDB backtraces. To debug issues involving code motion disable gdbjit (as it disables code motion).A comprehensive list of all flags can be found by running`out/x64.debug/d8 --help`.## TestingFor detailed instructions on running tests and interpreting failures, see thededicated test execution guidelines.Key commands summary:- **Run tests:** `tools/run-tests.py --progress dots --outdir=out/x64.optdebug`

Frequently asked questions

V8 Commands