Error Boundary Tester

Error Boundary Tester is a skill for Claude Code, Codex from PramodDutta/qaskills. It costs 26 tokens per session (7,618 once invoked), scanned A, original, MIT.

A guide to testing error boundaries, which are safeguards that show fallback content when one part of a React or other application interface fails.

In plain words
What is it for?
Use it to test fallback screens, recovery flows, and error reporting when isolated interface components fail.
Why use it?
It helps ensure a broken component does not crash the whole page and that users receive a useful recovery option.

Skill for Claude CodeCodex

Which agent this was written for is unclear — built for aider. Also seen: mentions Codex; built for aider; mentions Gemini CLI.

Needs its repository: it reads a path above its own folder, which exists only inside the repository. The line is import { ErrorBoundary } from '../../src/components/error-boundary';.

Good fit Use it to test fallback screens, recovery flows, and error reporting when isolated interface components fail.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/PramodDutta/qaskills
agentmods
npx agentmods add skills/pramoddutta/qaskills/error-boundary-tester

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 Error Boundary Tester

README.md
[![agentmods](https://agentmods.dev/badge/skills/pramoddutta/qaskills/error-boundary-tester.svg)](https://agentmods.dev/skills/pramoddutta/qaskills/error-boundary-tester)
Your own site
<a href="https://agentmods.dev/skills/pramoddutta/qaskills/error-boundary-tester"><img src="https://agentmods.dev/badge/skills/pramoddutta/qaskills/error-boundary-tester.svg" alt="Measured on agentmods" height="20"></a>
Per session 26 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 7,618 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
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 $0.00026 $0.07618
Opus 5 $0.00013 $0.03809
Sonnet 5 $0.00005 $0.01524
Haiku 4.5 $0.00003 $0.00762

Measured 4d ago against content hash fa7e41f8d129, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

Error Boundary Tester 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 4d 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.

seed-skills/error-boundary-tester/SKILL.md · 919 lines

How it starts

The opening of the file, as written. The whole thing — 919 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Error Boundary Tester Skill

You are an expert QA automation engineer specializing in error boundary and fault tolerance testing. When the user asks you to write, review, or debug tests for error boundaries and graceful degradation, follow these detailed instructions to validate that applications handle errors correctly, render appropriate fallback UIs, support error recovery, and prevent full-page crashes from isolated component failures.

Core Principles

  1. Errors are inevitable, crashes are not -- Every component will eventually encounter an error. Error boundaries ensure that a failure in one part of the UI does not bring down the entire application. Test that each error boundary contains failures within its scope.
  2. Fallback UI must be useful -- A blank screen or a raw error stack trace is not an acceptable fallback. Test that fallback UIs provide clear messaging, actionable recovery options, and a path back to a working state.
  3. Error reporting must be verified -- Error boundaries should report errors to monitoring services. Test that error logging occurs with sufficient context (component stack, user actions, application state) for debugging.
  4. Recovery must be tested explicitly -- Many error boundaries include a "Try Again" or "Reload" button. Test that these recovery mechanisms actually work and do not just re-render the same error state.
  5. Nested boundaries must scope correctly -- Inner error boundaries should catch errors before outer ones. If a sidebar widget fails, only the sidebar should show a fallback, not the entire page.
  6. Async errors need special handling -- Error boundaries in React only catch synchronous rendering errors by default. Async errors (from useEffect, event handlers, promises) require separate handling strategies that must be tested independently.

Project Structure

Organize error boundary test projects with this structure:

tests/
  error-boundaries/
    unit/
      error-boundary-component.test.tsx
      fallback-ui.test.tsx
      error-reporter.test.ts
      recovery-flow.test.tsx
    e2e/
      component-crash.spec.ts
      nested-boundary.spec.ts
      full-page-crash.spec.ts
      chunk-load-failure.spec.ts
      network-error.spec.ts
    integration/
      error-logging.spec.ts
      error-recovery.spec.ts
  helpers/
    error-injector.ts
    crash-component.tsx
    boundary-test-utils.ts
  fixtures/
    error-scenarios.fixture.ts
  mocks/
    error-reporter.mock.ts
playwright.config.ts
vitest.config.ts

Read the full file on GitHub · 919 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. 4d ago First seen · 919 lines · 26 tokens per session scan A fa7e41f8d129

Subscribe to this mod's changes

Error Boundary Tester is a skill published in the GitHub repository PramodDutta/qaskills (218 stars, last pushed 8d ago), licensed MIT. It adds 26 tokens to every session and 7,618 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 2026-09-03.

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