Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add mohitmishra786/low-level-dev-skills --skill strace-ltracegit clone --depth 1 https://github.com/mohitmishra786/low-level-dev-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/mohitmishra786/low-level-dev-skills/strace-ltrace)<a href="https://agentmods.dev/skills/mohitmishra786/low-level-dev-skills/strace-ltrace"><img src="https://agentmods.dev/badge/skills/mohitmishra786/low-level-dev-skills/strace-ltrace/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/mohitmishra786/low-level-dev-skills/strace-ltrace"><img src="https://agentmods.dev/badge/skills/mohitmishra786/low-level-dev-skills/strace-ltrace.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
- NVIDIA SkillSpector warn
SkillSpector: 2 findings, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high Privilege Escalation · line 122 Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
- high System Prompt Leakage · line 127 Skill contains instructions that could directly expose system prompts, internal rules, or hidden instructions to users or external parties.Fix: Remove any instructions that reveal, print, or output system prompts or internal rules. System instructions should never be exposed to end users.
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00090 | $0.01763 |
| Opus 5 | $0.00045 | $0.00881 |
| Sonnet 5 | $0.00018 | $0.00353 |
| Haiku 4.5 | $0.00009 | $0.00176 |
Grade A, and why
strace-ltrace scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 213 lines — stays where its author put it; the contents beside it link to each section on GitHub.
strace / ltrace
Purpose
Guide agents through tracing system calls with strace and library calls with ltrace — the most effective tools for diagnosing incorrect binary behaviour without a crash or debugger.
Triggers
- "My program behaves incorrectly — how do I trace what it's doing?"
- "How do I find what files a binary is opening?"
- "strace shows ENOENT — how do I interpret it?"
- "How do I trace network calls with strace?"
- "What is ltrace and how does it differ from strace?"
- "How do I trace a running process?"
Workflow
1. Basic strace usage
# Trace all syscalls of a command
strace ./myapp arg1 arg2
# Attach to running process
strace -p 12345
# Trace child processes too (-f = follow fork)
strace -f ./myapp
# Save to file (raw output — not stdout)
strace ./myapp 2> trace.txt
# Most useful: timestamps + summary
strace -t -f ./myapp 2>&1 | head -100
2. Filter by syscall category
# Trace file operations only
strace -e trace=file ./myapp
# Trace network syscalls
strace -e trace=network ./myapp
# Trace specific syscalls
strace -e trace=open,openat,read,write ./myapp
# Trace process management
strace -e trace=process ./myapp
# Trace memory operations
strace -e trace=memory ./myapp
# Trace signals
strace -e trace=signal ./myapp
# Multiple categories
strace -e trace=file,network ./myapp
| Category | Syscalls included |
|---|---|
file |
open, openat, stat, access, unlink, rename, ... |
network |
socket, connect, bind, accept, send, recv, ... |
process |
fork, exec, wait, clone, exit, ... |
memory |
mmap, munmap, mprotect, brk, ... |
signal |
kill, sigaction, sigprocmask, ... |
ipc |
pipe, socket pair, shmget, ... |
desc |
close, dup, poll, select, epoll, ... |
3. Interpreting common errors
# See return values and errors
strace -e trace=file ./myapp 2>&1 | grep -E "ENOENT|EPERM|EACCES|ENOTSUP"
| Error | Meaning | Common cause |
|---|---|---|
ENOENT |
No such file or directory | Config file missing, wrong path |
EACCES |
Permission denied | File permissions, SELinux |
EPERM |
Operation not permitted | Missing capability, suid needed |
EADDRINUSE |
Address already in use | Port already bound |
ETIMEDOUT |
Connection timed out | Network unreachable, firewall |
ECONNREFUSED |
Connection refused | Server not listening |
EAGAIN |
Resource temporarily unavailable | Non-blocking I/O, try again |
ENOMEM |
Out of memory | Allocation failed |
EBADF |
Bad file descriptor | Using closed/invalid fd |
ENOEXEC |
Exec format error | Wrong binary format for arch |
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 9d ago First seen · 213 lines · 90 tokens per session scan A 5556f01f71ff
strace-ltrace is a skill published in the GitHub repository mohitmishra786/low-level-dev-skills (203 stars, last pushed 2mo ago), licensed MIT. It adds 90 tokens to every session and 1,763 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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