error-handling-patterns

Master error handling patterns across languages including exceptions, Result types, error propagation, and graceful degradation to build resilient applications. Use when implementing error handling, designing APIs, or improving application reliability.

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npx tessl i github:wshobson/agents --skill error-handling-patterns

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Review — 66%

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Evaluation — 95%

Agent success when using this skill

Validation — 10 / 11 Passed

Validation for skill structure

SKILL.md

Review

Evals

Evaluation results

100%

39%

Order Data Service — TypeScript Implementation

TypeScript error classes and Result types

Criteria

Without context

With context

captureStackTrace

100%

Error name set

100%

Typed error fields

100%

Result type shape

50%

100%

Ok helper

100%

Err helper

100%

instanceof discrimination

100%

Default for known errors

100%

Re-throw unexpected

100%

No error code returns

100%

No empty catch blocks

100%

Promise rejections handled

100%

Without context: $0.3668 · 2m 15s · 14 turns · 15 in / 5,282 out tokens

With context: $1.1800 · 4m 8s · 43 turns · 43 in / 10,692 out tokens

92%

27%

Weather Data Pipeline — Resilient Python Implementation

Python exception hierarchy and resilience patterns

Criteria

Without context

With context

ApplicationError timestamp

100%

ApplicationError code and details

100%

ExternalServiceError service field

100%

Exception hierarchy

100%

Exponential backoff formula

83%

100%

Retry catches specific exceptions

100%

Circuit breaker three states

100%

OPEN state rejects immediately

100%

HALF_OPEN transition

100%

Context manager cleanup

Fail fast validation

100%

No log-and-rethrow

87%

100%

Without context: $0.5730 · 2m 35s · 23 turns · 23 in / 7,856 out tokens

With context: $1.3878 · 11m 33s · 41 turns · 36 in / 18,493 out tokens

95%

20%

User Registration Service — Validation and Profile Fetching

Error aggregation and graceful degradation

Criteria

Without context

With context

Error collector class

50%

100%

Collects all errors

100%

AggregateError for multiple

20%

80%

with_fallback function

30%

100%

Fallback invoked on failure

100%

Fallback error logged

62%

Meaningful error messages

100%

No validation error spam

100%

No swallowed errors

100%

Resource cleanup

75%

100%

No error code returns

100%

Without context: $0.3006 · 1m 47s · 13 turns · 13 in / 4,349 out tokens

With context: $0.4186 · 1m 44s · 15 turns · 16 in / 4,619 out tokens

Evaluated: 3 days ago
Agent: Claude Code

Table of Contents

Order Data Service — TypeScript Implementation Weather Data Pipeline — Resilient Python Implementation User Registration Service — Validation and Profile Fetching

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