nodejs-core

Overview of nodejs-core skill

What nodejs-core is for

The nodejs-core skill is for debugging and building at the Node.js internals layer: native addons, C++ bindings, V8 behavior, libuv scheduling, build failures, and performance issues that ordinary JavaScript prompts usually miss. It is most useful when you need nodejs-core for Backend Development work that crosses the JS/C++ boundary or depends on Node’s runtime mechanics.

Best-fit readers and jobs

Use the nodejs-core skill if you are:

• fixing binding.gyp or node-gyp build errors
• investigating crashes, segfaults, leaks, or flaky native tests
• writing or reviewing N-API, node-addon-api, or NAN-based code
• tuning event loop, worker thread, or thread pool behavior
• diagnosing V8 deopts, GC pressure, or hidden-class regressions

What makes it different

This skill is organized around actionable Node core rules, not a generic overview. The value is in the supporting rules/ files: they separate build workflow, V8, libuv, native memory, CLI options, and debugging paths so an agent can choose the right subsystem fast.

How to Use nodejs-core skill

Install and scope it correctly

Install nodejs-core with the repository skill command, then use it only when your task needs runtime internals or native build reasoning. If your problem is standard Express, API design, or plain TypeScript logic, this skill is probably too low-level.

Start from the right files

For nodejs-core install and first-pass reading, open:

• SKILL.md for scope and entry points
• rules/build-and-test-workflow.md for the required edit-build-test loop
• rules/build-system.md for compilation and binding.gyp context
• the subsystem rule that matches your issue, such as rules/napi.md, rules/libuv-event-loop.md, rules/v8-jit-compilation.md, or rules/debugging-native.md

Turn a rough task into a usable prompt

A weak request like “help with a Node addon crash” is too broad. A stronger nodejs-core usage prompt includes:

• platform: Linux/macOS/Windows
• Node version and build type
• exact failure mode: compile error, abort, hang, deopt, leak, wrong output
• subsystem hint: N-API, libuv, V8, child process, streams, or memory
• what changed recently
• the command or test that reproduces it

Example shape:
Use nodejs-core to diagnose a native addon crash on Node 22. The addon uses N-API, fails only in release builds, and crashes after a GC cycle. Focus on likely root causes, what to inspect in rules/napi.md and rules/memory-debugging.md, and the fastest repro steps.

Workflow that produces better results

Start with the matching rule file, then map the symptom to the smallest subsystem. For build issues, read the build workflow first; for runtime bugs, read the subsystem rule and compare your repro against the expected Node behavior. If the task involves edited src/ or lib/, rebuild before testing so you do not chase stale output.

nodejs-core skill FAQ

Is nodejs-core only for Node core contributors?

No. It is also useful for addon authors, platform engineers, and backend teams debugging production issues that happen below the JavaScript layer. You do not need to be contributing to Node core to use the nodejs-core skill.

How is it different from a normal prompt?

A normal prompt may guess at JavaScript-level fixes. nodejs-core is better when the answer depends on build flags, binary embedding, C++ bindings, V8 optimization behavior, or libuv internals. It reduces guesswork by steering the workflow toward the correct subsystem rules.

Is it beginner friendly?

Yes, if the question is concrete. It is less friendly for vague “why is Node slow?” requests. Beginners get better results when they provide a repro command, a stack trace, and the relevant subsystem. That makes nodejs-core usage much more precise.

When should I not use it?

Skip it for framework bugs, app architecture, or routine API usage. Also avoid it if you cannot supply a repro or at least a clear failure category; the skill is strongest when the problem already looks like a runtime, build, or native integration issue.

How to Improve nodejs-core skill

Give the skill the right evidence

The most useful inputs are exact: stack traces, build logs, node -p process.versions, compile flags, and the smallest reproduction. For nodejs-core for Backend Development, also include whether the service is CPU-bound, memory-bound, or blocked on I/O, because that changes whether V8, libuv, or native memory rules matter most.

Point to the subsystem early

Do not ask the model to search the entire repo mentally. Tell it whether the issue is closest to:

• rules/napi.md or rules/node-addon-api.md
• rules/v8-garbage-collection.md or rules/profiling-v8.md
• rules/libuv-event-loop.md or rules/libuv-thread-pool.md
• rules/debugging-native.md or rules/native-memory.md

Watch for common failure modes

The most common miss is treating a build problem like a runtime bug, or assuming a JS fix will solve a C++/binding issue. Another common miss is forgetting to rebuild after src/ or lib/ edits. If the first answer is too broad, iterate with one sharper repro, one smaller code sample, and one explicit “focus on build vs runtime” instruction.

Use the first answer as a narrowing pass

Treat the first output as a triage step: ask for the likely subsystem, the next diagnostic command, or the exact file to inspect next. Good nodejs-core results usually improve after one refinement cycle, especially when you add the failing command, the platform, and one concrete symptom instead of a general description.