New: 98,000+ skills indexed from GitHub repos with 100+ stars · every skill safety-checkedBrowse top skillsTop skills
Esc to closeBrowse all skills
Submit a skillBrowse skills
Submit a skillBrowse skills

Agent skill

Valgrind

by mohitmishra786 in mohitmishra786/low-level-dev-skills

Valgrind profiler skill for memory error detection and cache profiling.

MITAuto-check passedDevelopment

Install Valgrind

skills CLI
$ npx skills add mohitmishra786/low-level-dev-skills --skill valgrind -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install mohitmishra786/low-level-dev-skills valgrind --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/mohitmishra786/low-level-dev-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/profilers/valgrind .claude/skills/valgrind && rm -rf skills-src

Use ~/.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/

Facts

Skill name
valgrind
GitHub stars
252
Token cost
~1.3k tokens
SKILL.md length
422 words
Files
2 (incl. references)
Skills in repo
138
Repo updated
First seen
Licence
MIT

At a glance

Valgrind profiler skill for memory error detection and cache profiling.

  • Works in 8 steps: Memcheck — memory error detection → Understanding Memcheck output → Leak kinds → …
  • Running Memcheck to find heap corruption
  • SKILL.md covers Purpose, Triggers, Workflow and Related skills
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Valgrind is an agent skill from mohitmishra786/low-level-dev-skills. Valgrind profiler skill for memory error detection and cache profiling. Use when running Memcheck to find heap corruption, use-after-free, memory leaks, or uninitialised reads; or Cachegrind/Callgrind for cache simulation and function-level profiling. Activates on queries about valgrind, memcheck, heap leaks, use-after-free without sanitizers, cachegrind, callgrind, KCachegrind, or massif memory profiling.

Its SKILL.md is about 1.3k tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files, including reference files (for example `references/valgrind-vs-asan.md`).

It sits in Development, covering Performance optimization. The repository describes itself as: A curated suite of AI agent skills for systems and low-level programming with C/C++, Rust, and Zig toolchains, covering compilers, debuggers, profilers, build systems…. The licence is MIT.

When your agent uses it

  • Running Memcheck to find heap corruption
  • Uninitialised reads
  • Cachegrind/Callgrind for cache simulation and function-level profiling

Example prompts

  • “/valgrind”

Workflow steps

8 steps, taken from the step headings in SKILL.md.

  1. Memcheck — memory error detection
  2. Understanding Memcheck output
  3. Leak kinds
  4. Suppressions
  5. Cachegrind — cache simulation
  6. Callgrind — call graph profiling
  7. Massif — heap profiling
  8. Performance considerations

What it can do on your machine

Read from SKILL.md and the folder at commit bdc5847. 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 (its code samples are bash).

    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

Valgrind loads about 1.3k tokens when it runs, and up to ~1.8k if it reads all its reference files. Until then it costs about 105 tokens; SKILL.md has 422 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~105
When it runs · the whole SKILL.md, loaded when a task matches
~1.3k
With references · SKILL.md plus every file in references/, read only if the agent opens them
~1.8k

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

The full file from mohitmishra786/low-level-dev-skills at commit bdc5847, republished under its MIT licence (© mohitmishra786). 422 words, ~1,306 tokens.

Download SKILL.mdSave it as .claude/skills/valgrind/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.
name
valgrind
description
Valgrind profiler skill for memory error detection and cache profiling. Use when running Memcheck to find heap corruption, use-after-free, memory leaks, or uninitialised reads; or Cachegrind/Callgrind for cache simulation and function-level profiling. Activates on queries about valgrind, memcheck, heap leaks, use-after-free without sanitizers, cachegrind, callgrind, KCachegrind, or massif memory profiling.

Valgrind

Purpose

Guide agents through Valgrind tools: Memcheck for memory errors, Cachegrind for cache simulation, Callgrind for call graphs, and Massif for heap profiling.

Triggers

  • "My program has a memory leak / use-after-free"
  • "I can't use ASan — can I use Valgrind instead?"
  • "How do I profile cache behaviour without perf?"
  • "How do I visualize call graphs with Callgrind?"
  • "How do I profile heap allocation patterns?"
  • "Valgrind reports errors in third-party code I can't fix"

Workflow

1. Memcheck — memory error detection

Compile with -g -O1 for best results. -O0 is also fine; avoid -O2+ which can produce false positives.

bash
valgrind --tool=memcheck \
         --leak-check=full \
         --show-leak-kinds=all \
         --track-origins=yes \
         --error-exitcode=1 \
         ./prog [args]

Key flags:

FlagDefaultEffect
--leak-check=fullsummaryFull leak details
--show-leak-kinds=alldefiniteShow all leak kinds
--track-origins=yesnoShow where uninit values came from (slow)
--error-exitcode=N0Exit N if errors found (CI integration)
--log-file=filestderrSave report to file
--suppressions=filenoneSuppress known FPs
--gen-suppressions=yesnoPrint suppression directives for errors
--max-stackframe=N2000000Increase for deep stacks
--malloc-fill=0xABoffFill allocated memory (detect uninit use)
--free-fill=0xCDoffFill freed memory (detect use-after-free)
2. Understanding Memcheck output
text
==12345== Invalid read of size 4
==12345==    at 0x4007A2: foo (main.c:15)
==12345==    by 0x400846: main (main.c:30)
==12345==  Address 0x5204040 is 0 bytes after a block of size 40 alloc'd
==12345==    at 0x4C2FB0F: malloc (in /usr/lib/valgrind/vgpreload_memcheck.so)
==12345==    by 0x40074B: main (main.c:25)
  • Invalid read/write: out-of-bounds access; check array bounds
  • Use of uninitialised value: read before write; use --track-origins=yes
  • Invalid free / double free: mismatched malloc/free; check ownership
  • Definitely lost: reachable via no pointers; clear leak
  • Indirectly lost: lost through a chain; usually means one root leak
  • Possibly lost: might be pointing into the middle of a block; often FP with custom allocators
Show full SKILL.md (189 more words)Show less
3. Leak kinds
KindMeaning
Definitely lostNo pointer to block
Indirectly lostLost via another lost block
Possibly lostPointer into middle of block
Still reachablePointer exists at exit; not a leak but never freed

For library code: --show-leak-kinds=definite,indirect reduces noise from still-reachable.

4. Suppressions
bash
# Generate suppression for current error
valgrind --gen-suppressions=yes ./prog 2>&1 | grep -A20 '{'

# Example suppression file (valgrind.supp)
{
   openssl_uninit
   Memcheck:Cond
   fun:SHA256_Init
   ...
}

# Use suppression file
valgrind --suppressions=valgrind.supp ./prog
5. Cachegrind — cache simulation
bash
valgrind --tool=cachegrind ./prog

# Output: cachegrind.out.PID
# Annotate source
cg_annotate cachegrind.out.12345 --auto=yes

# Diff two runs
cg_diff cachegrind.out.before cachegrind.out.after

Key metrics:

  • I1mr / ILmr: L1/LL instruction cache miss rate
  • D1mr / DLmr: L1/LL data read miss rate
  • D1mw / DLmw: L1/LL data write miss rate
6. Callgrind — call graph profiling
bash
valgrind --tool=callgrind --callgrind-out-file=callgrind.out ./prog

# Analyse
callgrind_annotate callgrind.out

# Visualise in KCachegrind (GUI)
kcachegrind callgrind.out

Callgrind is slower than perf but works without root and provides exact call counts.

7. Massif — heap profiling
bash
valgrind --tool=massif ./prog

# Visualise
ms_print massif.out.PID | less

# GUI
massif-visualizer massif.out.PID

Massif shows heap usage over time; useful for finding peak allocation sites and tracking gradual leaks.

8. Performance considerations

Valgrind Memcheck runs ~10-50x slower than native. Mitigations:

  • Use a shorter representative workload
  • Use --error-exitcode=1 to fail fast in CI
  • Use ASan (-fsanitize=address) for faster memory checking during development
  • Reserve Valgrind for cases where ASan can't be used (old toolchains, production-like environments)

For a comparison of Valgrind vs ASan, see references/valgrind-vs-asan.md.

  • Use skills/runtimes/sanitizers for faster ASan/UBSan alternatives
  • Use skills/profilers/linux-perf for CPU-level profiling (faster than Cachegrind)
  • Use skills/profilers/flamegraphs to visualise Callgrind output

© mohitmishra786, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file (references) in skills/profilers/valgrind of mohitmishra786/low-level-dev-skills.

  • SKILL.md
  • references/valgrind-vs-asan.md

Open the folder on GitHubat commit bdc5847

Compare with similar skills

Valgrind 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.

Valgrind compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Valgrind this skillmohitmishra786/low-level-dev-skills252—~1.3kAutomated safety check: PassMIT
Code Review ChecklistshareAI-lab/learn-claude-code78k4 repos~1.1kAutomated safety check: PassMIT
LLM Torch Profiler Analysissgl-project/sglang37k2 repos~6.4kAutomated safety check: PassApache-2.0
Pycrazyguitar/pysheeet8.2k—~886Automated safety check: PassMIT
Cmux Debugging Guidemanaflow-ai/cmux28k1 repos~1.1kAutomated safety check: PassCustom licence
Analyzing .NET Performancedotnet/skills5.6k3 repos~3.1kAutomated safety check: PassMIT

Similar skills

  • Code Review Checklist

    shareAI-lab/learn-claude-code

    Reviews code against a five-part checklist covering security, correctness, performance, maintainability and testing, and reports findings in a fixed format.

    78k GitHub starsUsed in 4 repos~1.1k tokens
    DevelopmentAuto-check passed

  • LLM Torch Profiler Analysis

    sgl-project/sglang

    Unified LLM torch-profiler triage skill for sglang, vllm, TensorRT-LLM, and TokenSpeed.

    37k GitHub starsUsed in 2 repos~6.4k tokens
    DevelopmentAuto-check passed

  • Py

    crazyguitar/pysheeet

    Comprehensive Python programming reference covering syntax, concurrency, networking, databases, ML/LLM development, and HPC.

    8.2k GitHub stars~886 tokensUpdated 3 days ago
    DevelopmentAuto-check passed

  • Cmux Debugging Guide

    manaflow-ai/cmux

    Covers debug logging, the Debug menu, profiling rules and runtime pitfalls for working on the cmux macOS terminal app.

    28k GitHub starsUsed in 1 repo~1.1k tokens
    DevelopmentAuto-check passed

  • Analyzing .NET Performance

    dotnet/skills

    Official

    Scans C# and .NET code for about 50 performance anti-patterns and reports prioritized findings with concrete fixes, at a scan depth you choose.

    5.6k GitHub starsUsed in 3 repos~3.1k tokens
    DevelopmentAuto-check passed

  • Electron Heap Snapshot Analysis

    keybase/client

    Analyzes V8, Chrome and Electron .heapsnapshot files with Node scripts to find memory leaks, detached DOM nodes and the retainer paths that keep objects alive.

    9.3k GitHub stars~875 tokensUpdated today
    DevelopmentAuto-check passed

More from mohitmishra786/low-level-dev-skills

All 138 skills in this repo

  • ARM and AArch64 Assembly

    mohitmishra786/low-level-dev-skills

    Guides reading and writing AArch64 and ARM Thumb assembly: compiler output, inline asm, registers, the AAPCS calling convention and NEON or SVE basics.

    252 GitHub stars~1.9k tokensUpdated 3 mo ago
    Auto-check passed

  • RISC-V Assembly Guide

    mohitmishra786/low-level-dev-skills

    Reference for RISC-V assembly on RV32 and RV64: register names and calling convention, extension naming, GCC and Clang inline asm, and QEMU with GDB debugging.

    252 GitHub stars~1.8k tokensUpdated 3 mo ago
    Auto-check passed

  • x86-64 Assembly Reference

    mohitmishra786/low-level-dev-skills

    Explains x86-64 registers, the System V AMD64 calling convention, and how to read compiler-generated or inline assembly.

    252 GitHub stars~1.5k tokensUpdated 3 mo ago
    Auto-check passed

  • Bazel for C and C++

    mohitmishra786/low-level-dev-skills

    Guides your agent through Bazel for C/C++ projects: BUILD files, Bzlmod dependencies, toolchain registration, remote execution, dependency queries and sandbox debugging.

    252 GitHub stars~1.5k tokensUpdated 3 mo ago
    Auto-check passed

  • Binary Hardening

    mohitmishra786/low-level-dev-skills

    Binary hardening skill for security-hardened C/C++ builds. An agent skill from mohitmishra786/low-level-dev-skills.

    252 GitHub stars~2k tokensUpdated 3 mo ago
    Auto-check passed

  • Binutils

    mohitmishra786/low-level-dev-skills

    GNU binutils skill for binary manipulation and analysis. An agent skill from mohitmishra786/low-level-dev-skills.

    252 GitHub stars~1.2k tokensUpdated 3 mo ago
    Auto-check passed

Categories

Questions about Valgrind

What does Valgrind do?

Valgrind profiler skill for memory error detection and cache profiling. Valgrind is an agent skill from mohitmishra786/low-level-dev-skills. Valgrind profiler skill for memory error detection and cache profiling.

When should I use Valgrind?

Valgrind fits situations like: running Memcheck to find heap corruption; uninitialised reads; cachegrind/Callgrind for cache simulation and function-level profiling.

How do I install Valgrind in Claude Code?

Run `npx skills add mohitmishra786/low-level-dev-skills --skill valgrind -a claude-code`. Or copy the skill folder (skills/profilers/valgrind in mohitmishra786/low-level-dev-skills) into .claude/skills/valgrind in your project. Claude Code loads it when a task matches its description.

How do I install Valgrind in Codex?

Run `npx skills add mohitmishra786/low-level-dev-skills --skill valgrind -a codex`. Or copy the skill folder (skills/profilers/valgrind in mohitmishra786/low-level-dev-skills) into .agents/skills/valgrind in your project. Codex loads it when a task matches its description.

Can I use Valgrind 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 mohitmishra786/low-level-dev-skills --skill valgrind -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/valgrind, .gemini/skills/valgrind, .github/skills/valgrind and .opencode/skills/valgrind in your project.

What does Valgrind need to run?

SKILL.md names no scripts, command-line tools or credentials: Valgrind is instructions for the agent only.

Does Valgrind 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 Valgrind 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 Valgrind use?

Valgrind is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Valgrind use?

About 1.3k tokens (SKILL.md is roughly 5.2k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 457 tokens, read only when the agent opens those files.

What are the alternatives to Valgrind?

Skills that share tags, products or a category with Valgrind: Code Review Checklist (shareAI-lab/learn-claude-code, 78k stars), LLM Torch Profiler Analysis (sgl-project/sglang, 37k stars), Py (crazyguitar/pysheeet, 8.2k stars) and Cmux Debugging Guide (manaflow-ai/cmux, 28k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Valgrind?

mohitmishra786 (a GitHub user) maintains it in mohitmishra786/low-level-dev-skills, which has 252 GitHub stars. The repository holds 138 skills in this directory. The repository was last updated on June 27, 2026.

Source: mohitmishra786/low-level-dev-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.