v8

Manages git task isolation and environment setup in V8. Use at the start of any new task or bug fix. Do not use for general C++ editing.

Use this when you need to minimize a complex or bloated JavaScript test case (e.g., from a fuzzer or external report) into a minimal, readable reproduction for debugging V8 issues.

Guides the initial analysis and impact assessment of a V8 security report, strictly excluding implementation or fixing.

Use this skill to reproduce, profile, or analyze WebAssembly (Wasm) execution performance using d8 shell.

Executes and interprets V8 tests. Use when running unittests, cctest, or mjsunit, or when debugging test failures. Do not use for building.

Use this skill when designing, writing, or minimizing regression tests (e.g., mjsunit) for V8 bug fixes

Workflow for issue-based debugging in V8. Use when tasked with debugging a specific issue, usually associated with a Buganizer ID or a specific reproduction script. Do not use for performance regressions.

Workflow for general debugging tasks without the overhead of issue tracking. Use when investigating crashes, hangs, or unexpected behavior where no specific issue ID is provided. Do not use when issue ID is provided.

Workflow for automatically fixing errors or addressing comments on a Gerrit CL requested by the user.

Workflow for performance and memory evaluation in V8. Use when tasked with improving the performance or memory usage of a workload in V8. Do not use when debugging a crash or functionality issue.

Workflow for evaluating and refining agent debugging capabilities using designated test cases and Swarm principles. Use when evaluating subagent performance or creating benchmarks. Do not use for regular bug fixing.

Managing and querying Perfetto traces using the trace_processor MCP server.

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.

Checks if a POC provided by some JS and d8 flags is a vulnerability or just a regular bug.

Core skill for task scheduling and multi-agent coordination in V8 development. Use for any multi-step workflow or complex task. Do not use for simple linear tasks.

Maps the V8 dir/folder structure, component locations, and local documentation. Use when locating specific subsystems, mapping src/ code to docs/ design files, or understanding repository architecture.

Guides the methodology for investigating V8 concepts, codebase structure, performance, memory, and architecture. MANDATORY to use whenever triaging bugs, investigating crashes, reading C++ files, analyzing compiler optimizations (Ignition, Maglev, TurboFan, Turboshaft), or doing static research on V8 subsystems. Essential for locating high-level design documents in the local docs/ directory before reading C++ code. Do not use for raw build commands or Git workflows.

Workflow for agent self-improvement via isolated execution, evaluation, and process refinement. Use when evaluating historical bugs or self-correcting skills. Do not use for new feature development.

Handles installation and configuration of clangd-mcp for V8. Use when clangd-mcp is missing or needs configuration for the current workspace. Do not use for general C++ editing.

Running benchmarks with Crossbench.

Analyzes recent commits and uses a smart AI subagent to check if they invalidate any documentation in docs/.

Evaluates JavaScript using the official ECMAScript specification

Handles abstraction of environment-specific commands between Jetski and Gemini-CLI. Use when switching execution context between local terminal environments. Do not use for debugging logic issues.

How to use jsvu for cross-engine testing.

Provides expert guidance for navigating, implementing, and verifying V8 Torque (.tq) builtins. Use when modifying or debugging Torque files. Do not use for C++ macro builtins.

Adjusts instructions for V8 commands when running in a CiderG Chrome workspace environment. Trigger this when invoking any V8 binaries or running tests in a CiderG checkout.

Understanding v8.log files.

Profiling V8 execution.

Handles missing dependencies and configuration for V8 tools. Use when encountering missing tools, test runners, or workspace symlinks. Do not use for C++ coding issues.

Workflow for passing environment variables (like PATH) from the Orchestrator to subagents. Use when spawning subagents that need specific environment variables. Do not use for standard subagent execution.

Guide for breaking cyclic dependencies in V8 headers and resolving cascade IWYU failures.