Stack Trace Analyzer

A tool that reads error stack traces and explains where a failure started, what the relevant lines mean, and what may have caused it. A stack trace is the list of function calls recorded when a program crashes.

In plain words
What is it for?
Investigating crashes and failed builds in JavaScript, TypeScript, Python, Java, Go, Rust, and other common languages.
Why use it?
It turns difficult-to-read crash output or CI failures into a likely cause and concrete repair options.

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/notysoty/openagentskills/stack-trace-analyzer
Any agent
npx skills add Notysoty/openagentskills --skill stack-trace-analyzer
Clone the repo
git clone --depth 1 https://github.com/Notysoty/openagentskills

Made for: Claude Code, Codex.

Per session 24 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,515 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 $0.00024 $0.01515
Opus 5 $0.00012 $0.00758
Sonnet 5 $0.00005 $0.00303
Haiku 4.5 $0.00002 $0.00152

Measured 3d ago against content hash ced6a08a5865, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

Stack Trace Analyzer 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 3d 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/stack-trace-analyzer/SKILL.md · 147 lines

How it starts

The opening of the file, as written. The whole thing — 147 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Stack Trace Analyzer

What this skill does

This skill directs the agent to read a stack trace, identify which frame is the true origin of the bug (not just where the error was thrown), explain what each relevant frame means in plain English, diagnose the root cause, and propose 2–3 concrete fixes ranked by likelihood. It works with JavaScript, TypeScript, Python, Java, Go, Rust, and most other common stack trace formats.

Use this when you have a crash report, a CI failure, or a wall of red text in your terminal and you want to understand it fast.

How to use

Claude Code / Cline

Copy this file to .agents/skills/stack-trace-analyzer/SKILL.md in your project root.

Then paste the stack trace and ask:

  • "Analyze this stack trace using the Stack Trace Analyzer skill."
  • "Use the Stack Trace Analyzer skill — what went wrong and how do I fix it?"

Include any relevant context: the action that triggered the error, environment details (Node version, browser, OS), and any recent code changes.

Cursor

Add the "Prompt / Instructions" section below to your .cursorrules file. Then paste the stack trace into the chat.

Codex

Paste the full stack trace and the relevant source files into the chat, then include the instructions below. Codex benefits from seeing the actual source code so it can match line numbers to real code.

The Prompt / Instructions for the Agent

When given a stack trace, follow these steps:

  1. Identify the language and runtime from the trace format (Node.js, Python, JVM, Go panic, Rust panic, browser, etc.). Note the runtime version if visible.

  2. Parse the error header. Extract:

    • Error type (e.g., TypeError, NullPointerException, panic, KeyError)
    • Error message (the human-readable description)
    • Any error codes or HTTP status codes present
  3. Walk the stack frames top-to-bottom. For each frame that belongs to application code (not a framework or standard library):

    • State what the function does in plain English
    • Note the file path and line number
    • Explain why that frame is on the call stack (what called it)

Read the full file on GitHub · 147 lines

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. 3d ago First seen · 147 lines · 24 tokens per session scan A ced6a08a5865

Subscribe to this mod's changes

Stack Trace Analyzer is a skill published in the GitHub repository Notysoty/openagentskills (9 stars, last pushed 19d ago), licensed MIT. It adds 24 tokens to every session and 1,515 once invoked, about $0.0001 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 2026-08-31.

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