Rspack Debugging

When Rspack crashes with a segfault or hangs during builds, this gives you a structured way to capture what's actually happening under the hood using LLDB. It handles the annoying parts automatically: swapping in debug symbol packages, setting up non-interactive debugging sessions, and routing you to the right workflow based on whether you're dealing with HMR crashes, build hangs, or those maddeningly intermittent deadlocks. The coredump analysis guides are especially useful for bugs you can't reliably reproduce. Just remember to save your backtraces to the debug_artifacts folder before your session ends, and restore your production packages when you're done.

skills.sh installs: 277
GitHub stars: 98
last updated: Aug 21, 2026

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Install

$ npx -y skills add rstackjs/agent-skills --skill rspack-debugging --agent claude-code

Installs into .claude/skills of the current project.

Files

Rspack debugging

Overview

This Skill guides you on how to capture the underlying crash state of Rspack (which is based on Rust). By using the LLDB debugger and Rspack packages with debug symbols, we can obtain detailed stack backtraces, which are crucial for pinpointing issues. The guides focus on non-interactive, automated debugging to easily capture backtraces.

Preparation

Before starting, please ensure your environment meets the requirements.

Install LLDB: You must install the LLDB debugger.
- macOS: Run xcode-select --install
- Linux: Install the lldb package (e.g., apt-get install lldb)
- Detailed guide: references/lldb.md
Replace Debug Packages: Production packages like @rspack/core have debug symbols stripped. They must be replaced with the @rspack-debug/* series packages to see useful stack information.

Automatic Replacement Script:

Resolve the bundled scripts/setup_debug_deps.cjs relative to the Skill root while keeping the working directory in the user's project, then run: