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tessl-labs/fastapi-security-basics

Security defaults that belong in every FastAPI application from day one.

93

7.00x
Quality

90%

Does it follow best practices?

Impact

98%

7.00x

Average score across 5 eval scenarios

SecuritybySnyk

Passed

No known issues

Overview
Quality
Evals
Security
Files

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 what security features it covers (CORS, rate limiting, security headers, etc.) and provides explicit, actionable triggers for when to apply it (any FastAPI app creation or modification). The description uses third person voice appropriately and includes both technical terms and practical code patterns that would naturally trigger selection.

DimensionReasoningScore

Specificity

Lists multiple specific concrete actions: 'CORS, rate limiting, security headers, trusted hosts, input validation, HTTPS redirect, and request size limits.' These are all concrete, specific security features.

3 / 3

Completeness

Clearly answers both what ('CORS, rate limiting, security headers...') AND when ('Apply these whenever you create or modify any FastAPI app', 'If you are writing app = FastAPI(), you must also add these'). Explicit trigger guidance is provided.

3 / 3

Trigger Term Quality

Includes natural keywords users would say: 'FastAPI', 'security', 'CORS', 'rate limiting', 'HTTPS', and the explicit code pattern 'app = FastAPI()'. Good coverage of both technical terms and framework-specific language.

3 / 3

Distinctiveness Conflict Risk

Highly specific to FastAPI security defaults with clear niche. The explicit mention of 'FastAPI' and specific security features like 'trusted hosts' and 'request size limits' makes it unlikely to conflict with general security or other 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 highly actionable security skill with excellent executable examples and clear workflow guidance. The WRONG/RIGHT pattern effectively teaches correct implementation, and the middleware order section addresses a common pitfall. The main weakness is verbosity - the content could be more concise by reducing repetition between the detailed sections and the final checklist, and by potentially splitting detailed examples into separate files.

Suggestions

Reduce redundancy by removing the final checklist or converting it to a brief summary that references the detailed sections above rather than restating all requirements

Consider moving the detailed WRONG/RIGHT code examples to a separate EXAMPLES.md file, keeping only the RIGHT examples in the main skill

DimensionReasoningScore

Conciseness

The skill is comprehensive but includes some redundancy - the WRONG/RIGHT pattern repeats explanations, and some rules are stated multiple times across sections. The checklist at the end duplicates information already covered in detail above.

2 / 3

Actionability

Excellent actionability with fully executable, copy-paste ready code examples for every security measure. Each section provides complete, working code with proper imports and configuration, plus explicit WRONG vs RIGHT comparisons.

3 / 3

Workflow Clarity

Clear sequencing with explicit middleware order section explaining why order matters. The numbered list of 7 requirements, the middleware order code block, and the final checklist provide unambiguous workflow guidance for implementing security in FastAPI apps.

3 / 3

Progressive Disclosure

The skill is self-contained with good internal structure (numbered sections, clear headers), but at ~350 lines it could benefit from splitting detailed examples into separate reference files. The verifiers section at the end provides good external references 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.

Validation10 / 11 Passed

Validation for skill structure

CriteriaDescriptionResult

frontmatter_unknown_keys

Unknown frontmatter key(s) found; consider removing or moving to metadata

Warning

Total

10

/

11

Passed

Reviewed

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