runtime-error-explainer

runtime-error-explainer is a skill for Claude Code, Codex from ArabelaTso/Skills-4-SE. It costs 98 tokens per session (4,476 once invoked), scanned A, original, Apache-2.0.

A guide to understanding runtime errors, compilation failures, and dependency problems in Python or Java programs. It reads error messages and stack traces, then explains their likely causes in plain language.

In plain words
What is it for?
Use it to investigate exceptions, syntax and type errors, failed imports, dependency issues, and the code changes needed to resolve them.
Why use it?
It turns confusing failure output into a clear diagnosis and a concrete fix. This reduces the time spent searching through code and documentation to understand what went wrong.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/arabelatso/skills-4-se/runtime-error-explainer
Any agent
npx skills add ArabelaTso/Skills-4-SE --skill runtime-error-explainer
Clone the repo
git clone --depth 1 https://github.com/ArabelaTso/Skills-4-SE

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 runtime-error-explainer

README.md
[![agentmods](https://agentmods.dev/badge/skills/arabelatso/skills-4-se/runtime-error-explainer.svg)](https://agentmods.dev/skills/arabelatso/skills-4-se/runtime-error-explainer)
Your own site
<a href="https://agentmods.dev/skills/arabelatso/skills-4-se/runtime-error-explainer"><img src="https://agentmods.dev/badge/skills/arabelatso/skills-4-se/runtime-error-explainer.svg" alt="Measured on agentmods" height="20"></a>
Per session 98 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,476 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00098 $0.04476
Opus 5 $0.00049 $0.02238
Sonnet 5 $0.00020 $0.00895
Haiku 4.5 $0.00010 $0.00448

Measured 2d ago against content hash 0747239ab130, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

runtime-error-explainer 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 2d 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.

skills/runtime-error-explainer/SKILL.md · 850 lines

How it starts

The opening of the file, as written. The whole thing — 850 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Runtime Error Explainer

Analyze runtime and compilation errors with clear explanations and actionable fixes.

Core Capabilities

This skill helps debug runtime and compilation errors by:

  1. Parsing error output - Extract key information from error messages and stack traces
  2. Identifying root causes - Determine why errors occur during execution or compilation
  3. Explaining clearly - Translate technical errors into understandable language
  4. Providing fixes - Suggest concrete code changes with before/after examples
  5. Preventing recurrence - Recommend best practices to avoid similar errors

Error Analysis Workflow

Step 1: Gather Error Context

Collect all relevant information about the error.

Essential Information:

  • Complete error message and stack trace
  • Programming language and version
  • Code that triggered the error
  • How the error was triggered (command, action, input)

Additional Context (if available):

  • Recent code changes
  • Environment details (OS, IDE, dependencies)
  • Input data or parameters that caused error
  • Configuration files

How to Gather:

# Python - Run with full traceback
python script.py

# Python - More verbose error output
python -v script.py

# Java - Compile with verbose output
javac -verbose MyClass.java

# Java - Run with stack trace
java -XX:+ShowCodeDetailsInExceptionMessages MyClass

Step 2: Categorize the Error

Identify the error type using references/error_catalog.md:

Error Categories:

  1. Syntax/Compilation Errors

    • Python: SyntaxError, IndentationError
    • Java: Compilation errors (missing semicolons, type errors)
  2. Runtime Errors

    • Python: TypeError, AttributeError, ValueError, KeyError, IndexError
    • Java: NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException
  3. Import/Dependency Errors

    • Python: ImportError, ModuleNotFoundError
    • Java: ClassNotFoundException, NoClassDefFoundError
  4. Type Errors

    • Python: TypeError (wrong types in operations)
    • Java: Type mismatch compilation errors

Read the full file on GitHub · 850 lines

Files

What ships with it

2 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. 2d ago First seen · 850 lines · 98 tokens per session scan A 0747239ab130

Subscribe to this mod's changes

runtime-error-explainer is a skill published in the GitHub repository ArabelaTso/Skills-4-SE (248 stars, last pushed 15d ago), licensed Apache-2.0. It adds 98 tokens to every session and 4,476 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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