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.
34
0%
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
0%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 essentially a title repeated as trigger terms with no substantive content. It fails to describe what the skill does, when it should be used, or what distinguishes it from other backend development skills. It reads like auto-generated boilerplate rather than a useful skill description.
Suggestions
Add concrete actions the skill performs, e.g., 'Creates error handling middleware for Express/Node.js applications, including centralized error 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, exception middleware, custom error responses, Express error handlers, try-catch patterns, or 500 error pages.'
Remove the duplicate trigger term ('error handler middleware' is listed twice) and expand with natural variations users would actually say, such as 'error handling', 'exception handling', 'error middleware', 'catch errors', 'error responses'.
| 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 'what' is extremely weak (no concrete actions described) and the 'when' is missing entirely—there's no explicit guidance on when Claude should select this skill beyond the auto-trigger label. No 'Use when...' clause present. | 1 / 3 |
Trigger Term Quality | The trigger terms are just 'error handler middleware' repeated twice. Missing 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 description is too vague to distinguish from other backend development skills. 'Backend Development' category and 'error handler middleware' without specifics could overlap with general backend skills, Express middleware skills, logging skills, or any error-related skill. | 1 / 3 |
Total | 4 / 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 entirely a self-referential meta-description with no actual instructional content. It describes what it claims to do (error handler middleware guidance) without providing any concrete implementation details, code examples, patterns, or workflows. It is essentially a placeholder that adds no value beyond what Claude already knows.
Suggestions
Replace the meta-description with actual error handler middleware implementations in at least one language (e.g., Express.js error middleware, Python Flask/FastAPI error handlers) with executable code examples.
Add a clear workflow for implementing error handling middleware: define error classes, create the middleware, register it, and validate with test cases.
Include concrete patterns such as structured error responses (JSON schema), error classification (operational vs programmer errors), logging integration, and status code mapping.
Remove the 'When to Use', 'Example Triggers', and 'Capabilities' sections entirely—these are routing metadata that waste tokens and provide no instructional value.
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The entire content is meta-description about when the skill activates and what it claims to do, without any actual technical content. Every line explains things Claude already knows or could infer from the skill's existence. | 1 / 3 |
Actionability | There is zero concrete guidance—no code, no commands, no specific patterns, no examples of error handler middleware implementation. It only describes what it could do rather than instructing how to do anything. | 1 / 3 |
Workflow Clarity | No workflow, steps, or process is defined. The skill mentions 'step-by-step guidance' as a capability but provides none. There are no validation checkpoints or sequences. | 1 / 3 |
Progressive Disclosure | The content is a flat, monolithic description with no references to detailed materials, no links to implementation guides, and no structured navigation to deeper content. | 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
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- Reviewed
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