tessl-labs/fastapi-error-handling
Production error handling for FastAPI — exception handlers, structured error
93
90%
Does it follow best practices?
Impact
99%
6.18xAverage score across 5 eval scenarios
Passed
No known issues
Quality
Discovery
100%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 is an excellent skill description that clearly defines its scope (FastAPI production error handling), lists specific capabilities, and provides explicit trigger conditions including observable symptoms like 'raw 500s' and 'inconsistent error response formats'. It uses proper third-person voice and is concise without being vague.
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Lists multiple specific concrete actions: exception handlers, structured error responses, async error patterns, and graceful shutdown. These are distinct, well-defined capabilities. | 3 / 3 |
Completeness | Clearly answers both what ('exception handlers, structured error responses, async error patterns, and graceful shutdown') and when ('when building or reviewing FastAPI backends, when you see unhandled exceptions returning raw 500s, or when error response formats are inconsistent') with explicit trigger scenarios. | 3 / 3 |
Trigger Term Quality | Includes strong natural trigger terms users would say: 'FastAPI', 'exception handlers', 'error responses', 'unhandled exceptions', 'raw 500s', 'error response formats', 'async error patterns', 'graceful shutdown'. These cover common ways developers describe these problems. | 3 / 3 |
Distinctiveness Conflict Risk | Highly distinctive — scoped specifically to FastAPI error handling in production contexts. The combination of framework (FastAPI), concern (error handling), and specific symptoms (raw 500s, inconsistent error formats) makes it unlikely to conflict with general Python, general error handling, or other web framework skills. | 3 / 3 |
Total | 12 / 12 Passed |
Implementation
77%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This is a strong, actionable skill with fully executable code examples and a clear workflow for adding error handling to FastAPI apps. Its main weakness is moderate verbosity — some explanatory sections (like 'Why all three?' and 'The Problem') could be trimmed since Claude understands these concepts. The structure is good but the content is dense enough that splitting advanced topics into separate files would improve progressive disclosure.
Suggestions
Trim or remove the 'Why all three?' explanation block — Claude understands exception handler precedence and can infer the consequences of missing handlers.
Consider moving the 'Applying to Existing Code' migration steps and the 'Error Response Format' examples into a separate reference file to keep SKILL.md leaner.
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | Mostly efficient but includes some unnecessary explanation. The 'Why all three?' section is somewhat verbose explaining things Claude would understand, and 'The Problem' section restates what the description already covers. The 'Code after yield runs on shutdown...' explanation is borderline but useful for a nuanced behavior. | 2 / 3 |
Actionability | Fully executable code throughout — error classes, exception handlers, route usage, and lifespan shutdown are all copy-paste ready. The 'Applying to Existing Code' section gives concrete search-and-replace steps. Every code block is complete and runnable. | 3 / 3 |
Workflow Clarity | Clear numbered sequence (define errors → register handlers → use in routes → add shutdown). The 'Applying to Existing Code' section provides a clear migration workflow. The checklist at the end serves as a validation checkpoint. The skill doesn't involve destructive operations, so the level of validation is appropriate. | 3 / 3 |
Progressive Disclosure | The content is well-structured with clear sections, but it's somewhat long for a single SKILL.md file. The error response format examples, the detailed 'Why all three?' explanation, and the migration checklist could potentially be split into referenced files. The verifier references at the bottom are good but the main content is monolithic. | 2 / 3 |
Total | 10 / 12 Passed |
Validation
90%Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.
Validation — 10 / 11 Passed
Validation for skill structure
| Criteria | Description | Result |
|---|---|---|
frontmatter_unknown_keys | Unknown frontmatter key(s) found; consider removing or moving to metadata | Warning |
Total | 10 / 11 Passed | |
Reviewed
Table of Contents