shellcheck

shellcheck is a skill for Claude Code, Codex from julianobarbosa/claude-code-skills. It costs 47 tokens per session (1,292 once invoked), scanned A, original, MIT.

A static checker for Bash and other shell scripts. Static analysis examines source code without running it, looking for syntax mistakes, unsafe quoting, portability problems, and style issues.

In plain words
What is it for?
Use it to analyze, fix, or configure shell-script checks and add them to a CI/CD pipeline, which automatically tests changes during development.
Why use it?
It finds common shell-script bugs that can cause unexpected commands, broken arguments, or failures on other systems. It can also report warnings using ShellCheck error codes.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to analyze, fix, or configure shell-script checks and add them to a CI/CD pipeline, which automatically tests changes during development.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/julianobarbosa/claude-code-skills/shellcheck
Install

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.

Any agent
npx skills add julianobarbosa/claude-code-skills --skill shellcheck
Clone the repo
git clone --depth 1 https://github.com/julianobarbosa/claude-code-skills

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for shellcheck

README.md
[![agentmods](https://agentmods.dev/badge/skills/julianobarbosa/claude-code-skills/shellcheck/github.svg)](https://agentmods.dev/skills/julianobarbosa/claude-code-skills/shellcheck)
Your own site
<a href="https://agentmods.dev/skills/julianobarbosa/claude-code-skills/shellcheck"><img src="https://agentmods.dev/badge/skills/julianobarbosa/claude-code-skills/shellcheck/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.

agentmods 80×15 button for shellcheck

Your own site · 80×15
<a href="https://agentmods.dev/skills/julianobarbosa/claude-code-skills/shellcheck"><img src="https://agentmods.dev/badge/skills/julianobarbosa/claude-code-skills/shellcheck.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,292 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

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 →

  • medium Data Exfiltration · line 25
    Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
    Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00047 $0.01292
Opus 5 $0.00023 $0.00646
Sonnet 5 $0.00009 $0.00258
Haiku 4.5 $0.00005 $0.00129

Measured 8d ago against content hash 69c121042d7b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

shellcheck scanned grade A with 1 finding 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 8d 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -s -X POST http://localhost:8888/notify \
skills/shellcheck/SKILL.md · 142 lines

How it starts

The opening of the file, as written. The whole thing — 142 lines — stays where its author put it; the contents beside it link to each section on GitHub.

ShellCheck - Shell Script Static Analysis

Auto-routes when user mentions shellcheck, shell linting, bash script analysis, or SC error codes.

Overview

ShellCheck is a GPLv3-licensed static analysis tool that identifies bugs in bash/sh shell scripts. It detects:

  • Syntax errors and parsing issues
  • Semantic problems causing unexpected behavior
  • Quoting issues and word splitting bugs
  • POSIX compatibility warnings
  • Style and best practice violations

Voice Notification

When executing a workflow, do BOTH:

  1. Send voice notification:

    curl -s -X POST http://localhost:8888/notify \
      -H "Content-Type: application/json" \
      -d '{"message": "Running the WORKFLOWNAME workflow from the ShellCheck skill"}' \
      > /dev/null 2>&1 &
    
  2. Output text notification:

    Running the **WorkflowName** workflow from the **ShellCheck** skill...
    

Workflow Routing

Workflow Trigger File
Analyze "shellcheck this", "lint script", "check shell" Workflows/Analyze.md
Fix "fix shell errors", "apply shellcheck fixes" Workflows/Fix.md
Setup "setup shellcheck", "configure shellcheck" Workflows/Setup.md
Explain "explain SC2086", "what is SC code" Workflows/Explain.md

Quick Reference

Basic Usage

# Check a script
shellcheck myscript.sh

# Specify shell dialect
shellcheck -s bash myscript.sh

# Exclude specific codes
shellcheck -e SC2086,SC2046 myscript.sh

# Output formats
shellcheck -f gcc myscript.sh      # Editor integration
shellcheck -f json myscript.sh     # Machine readable
shellcheck -f diff myscript.sh     # Auto-fix patches

Common SC Codes

Code Issue Fix
SC2086 Unquoted variable "$var"
SC2046 Unquoted command substitution "$(cmd)"
SC2034 Unused variable Remove or export
SC2154 Unassigned variable Assign or disable
SC2155 Declare and assign separately Split declaration

Read the full file on GitHub · 142 lines

Files

What ships with it

9 files 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.

Changes

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.

  1. 8d ago First seen · 142 lines · 47 tokens per session scan A 69c121042d7b

Subscribe to this mod's changes

shellcheck is a skill published in the GitHub repository julianobarbosa/claude-code-skills (10 stars, last pushed 16d ago), licensed MIT. It adds 47 tokens to every session and 1,292 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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