handling-errors
Prevents silent failures and context loss in error handling. Use when writing try-catch blocks, designing error propagation, reviewing catch blocks, or implementing Result patterns.
What this skill does
# Handling Errors
## Error Categories
| Type | Examples | Handling |
| ------------ | ---------------------------------- | --------------------------- |
| **Expected** | Validation, Not found, Unauthorized| Return Result type, log info|
| **Transient**| Network timeout, Rate limit | Retry with backoff, log warn|
| **Unexpected**| Null reference, DB crash | Log error, show support ID |
| **Critical** | Auth down, Payment gateway offline | Circuit breaker, alert |
## Fail Fast vs Degrade Gracefully
**Fail fast** for critical dependencies:
```typescript
await connectToDatabase(); // Throws on failure - app can't run without it
```
**Degrade gracefully** for optional features:
```typescript
const prefs = await loadPreferences(userId).catch(() => DEFAULT_PREFS);
```
## Log at the Right Layer
```typescript
// ❌ Logging at every layer = same error 3x
async function fetchData() {
try { return await fetch(url); }
catch (e) { console.error("Fetch failed:", e); throw e; }
}
// ✅ Log once where handled
async function fetchData() {
const response = await fetch(url);
if (!response.ok) throw new Error(`HTTP ${response.status}`);
return response;
}
// Top level logs the error once
```
## Language-Specific Patterns
- **TypeScript/React**: See [references/typescript-react.md](references/typescript-react.md) for Error Boundaries, typed errors, Result pattern, UI display
- **Python**: See [references/python.md](references/python.md) for EAFP, exception chaining, context managers
- **Go**: See [references/go.md](references/go.md) for explicit error returns, wrapping with %w, sentinel errors
## Anti-Patterns
| Pattern | Problem | Fix |
|---------|---------|-----|
| Empty catch blocks | Hides errors | Log or re-throw |
| `return false` on error | Loses context | Return Result type |
| Generic "Error" messages | Undebuggable | Include what/why/context |
| Logging same error at each layer | Log pollution | Log once at boundary |
| Bare `except:` / `catch (e)` all | Catches system signals | Catch specific types |
Related in Writing & Docs
jax-development
IncludedUse this skill when the user is writing, debugging, profiling, refactoring, reviewing, benchmarking, parallelising, exporting, or explaining JAX code, or when they mention JAX, jax.numpy, jit, grad, value_and_grad, vmap, scan, lax, random keys, pytrees, jax.Array, sharding, Mesh, PartitionSpec, NamedSharding, pmap, shard_map, Pallas, XLA, StableHLO, checkify, profiler, or the JAX repo. It helps turn NumPy or PyTorch-style code into pure functional JAX, fix tracer/control-flow/shape/PRNG bugs, remove recompiles and host-device syncs, choose transforms and sharding strategies, inspect jaxpr/lowering/IR, and benchmark compiled code correctly.
nature-article-writer
IncludedDrafts, rewrites, diagnostically critiques, and style-calibrates primary research manuscripts for Nature and Nature Portfolio journals. Use when the user wants a Nature-style title, summary paragraph or abstract, introduction, results, discussion, methods, figure legends, presubmission enquiry, cover letter, reviewer response, or when a scientific draft sounds generic, jargon-heavy, structurally weak, or AI-ish and needs precise, broad-reader-friendly prose without inventing data, analyses, or references. Best for primary research articles and letters rather than reviews or press releases unless explicitly adapting one.
deckrd
IncludedDocument-driven framework that derives requirements, specifications, implementation plans, and executable tasks from goals through structured AI dialogue. Use when user says "write requirements", "create spec", "plan implementation", "derive tasks", "structure this feature", "break down into tasks", or "document this module". Also use for reverse engineering existing code into docs (/deckrd rev). Do NOT use for direct code writing — use /deckrd-coder after tasks are generated. Do NOT use when the user only wants to run or fix existing code without planning.
clinical-decision-support
IncludedGenerate professional clinical decision support (CDS) documents for pharmaceutical and clinical research settings, including patient cohort analyses (biomarker-stratified with outcomes) and treatment recommendation reports (evidence-based guidelines with decision algorithms). Supports GRADE evidence grading, statistical analysis (hazard ratios, survival curves, waterfall plots), biomarker integration, and regulatory compliance. Outputs publication-ready LaTeX/PDF format optimized for drug development, clinical research, and evidence synthesis.
handling-sf-data
IncludedSalesforce data operations with 130-point scoring. Use this skill to create, update, delete, bulk import/export, generate test data, and clean up org records using sf CLI and anonymous Apex. TRIGGER when: user creates test data, performs bulk import/export, uses sf data CLI commands, needs data factory patterns for Apex tests, or needs to seed/clean records in a Salesforce org. DO NOT TRIGGER when: SOQL query writing only (use querying-soql), Apex test execution (use running-apex-tests), or metadata deployment (use deploying-metadata).
accelint-ac-to-playwright
IncludedConvert and validate acceptance criteria for Playwright test automation. Use when user asks to (1) review/evaluate/check if AC are ready for automation, (2) assess if AC can be converted as-is, (3) validate AC quality for Playwright, (4) turn AC into tests, (5) generate tests from acceptance criteria, (6) convert .md bullets or .feature Gherkin files to Playwright specs, (7) create test automation from requirements. Handles both bullet-style markdown and Gherkin syntax with JSON test plan generation and validation.