error-handler-middleware
Error Handler Middleware - Auto-activating skill for Backend Development. Triggers on: error handler middleware, error handler middleware Part of the Backend Development skill category.
36
3%
Does it follow best practices?
Impact
99%
1.03xAverage score across 3 eval scenarios
Passed
No known issues
Optimize this skill with Tessl
npx tessl skill review --optimize ./planned-skills/generated/06-backend-dev/error-handler-middleware/SKILL.mdQuality
Discovery
7%Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.
This description is extremely weak—it essentially just repeats the skill name without describing any concrete capabilities, use cases, or meaningful trigger terms. It reads like auto-generated boilerplate rather than a useful description that would help Claude select the right skill from a large pool. The duplicate trigger term and lack of any 'Use when...' guidance make it nearly useless for skill selection.
Suggestions
Add specific concrete actions the skill performs, e.g., 'Creates error handling middleware for Express/Node.js applications, including centralized exception catching, structured error responses, logging integration, and HTTP status code mapping.'
Add an explicit 'Use when...' clause with natural trigger terms, e.g., 'Use when the user asks about error handling in backend APIs, creating middleware for catching exceptions, formatting error responses, or setting up centralized error handling in Express, Koa, or similar frameworks.'
Expand trigger terms to include natural variations users would say: 'error handling', 'exception middleware', 'catch errors', 'error response formatting', 'global error handler', '500 errors', 'try-catch middleware'.
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | The description names 'error handler middleware' but provides no concrete actions—it doesn't describe what the skill actually does (e.g., creates middleware, catches exceptions, formats error responses, logs errors). It's essentially just a label repeated. | 1 / 3 |
Completeness | The description fails to answer 'what does this do' beyond naming itself, and the 'when' clause is just a repetition of the skill name rather than meaningful trigger guidance. There is no explicit 'Use when...' clause with actionable context. | 1 / 3 |
Trigger Term Quality | The trigger terms are just 'error handler middleware' repeated twice. It misses natural variations users would say like 'error handling', 'exception middleware', 'catch errors', 'error response', 'Express error handler', '500 errors', etc. | 1 / 3 |
Distinctiveness Conflict Risk | The term 'error handler middleware' is somewhat specific to backend middleware patterns, which gives it a narrower niche than fully generic descriptions. However, it could overlap with general error handling skills or backend development skills due to lack of specificity about what framework or actions it covers. | 2 / 3 |
Total | 5 / 12 Passed |
Implementation
0%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This skill is essentially a placeholder with no substantive content. It repeatedly describes itself in abstract terms without providing any actual error handler middleware implementation guidance, code examples, or concrete patterns. It fails on every dimension because it contains no actionable technical content whatsoever.
Suggestions
Add concrete, executable error handler middleware examples in at least one language (e.g., Express.js error middleware, Python Flask/FastAPI exception handlers) with copy-paste ready code.
Define a clear workflow for implementing error handler middleware: e.g., 1) Create error classes, 2) Implement middleware function, 3) Register middleware, 4) Test with sample errors.
Remove all meta-description sections (Purpose, When to Use, Capabilities, Example Triggers) and replace with actual technical content—patterns, anti-patterns, and production-ready configurations.
Add specific guidance on error response formats, logging integration, and environment-aware error detail exposure (dev vs production) rather than vague references to 'best practices'.
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The content is entirely filler and meta-description. It explains what the skill does in abstract terms without providing any actual technical content. Every section restates the same vague idea—that this skill helps with 'error handler middleware'—without adding substance. | 1 / 3 |
Actionability | There is zero concrete guidance—no code examples, no specific commands, no patterns, no middleware implementations. The skill describes rather than instructs, offering nothing executable or copy-paste ready. | 1 / 3 |
Workflow Clarity | No workflow, steps, or process is defined. The skill mentions 'step-by-step guidance' as a capability but never actually provides any steps, sequences, or validation checkpoints. | 1 / 3 |
Progressive Disclosure | The content is a monolithic block of vague descriptions with no references to supporting files, no structured navigation, and no separation of overview from detailed content. There are no bundle files to support it either. | 1 / 3 |
Total | 4 / 12 Passed |
Validation
81%Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.
Validation — 9 / 11 Passed
Validation for skill structure
| Criteria | Description | Result |
|---|---|---|
allowed_tools_field | 'allowed-tools' contains unusual tool name(s) | Warning |
frontmatter_unknown_keys | Unknown frontmatter key(s) found; consider removing or moving to metadata | Warning |
Total | 9 / 11 Passed | |
- Commit
13d35b8
- Reviewed
Table of Contents
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