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fastly

Configures, manages, and debugs the Fastly CDN platform — covering service and backend setup, caching and VCL, security features like DDoS/WAF/NGWAF/rate limiting/bot management, TLS certificates and cache purging, the Compute platform, and the REST API. Use when working with Fastly services or domains, setting up edge caching or origin shielding, configuring security features, making Fastly API calls, enabling products, or looking up Fastly documentation. Also applies when troubleshooting 503 errors or SSL/TLS certificate mismatches on Fastly, and for configuring logging endpoints, load balancing, ACLs, or edge dictionaries. Read the relevant reference file before writing any Fastly API call or curl command — request field names (e.g. the backend fields override_host, ssl_cert_hostname, ssl_sni_hostname, use_ssl) are easy to misremember, and a wrong name causes a silent 503 instead of an error, so do not rely on training-knowledge field names.

77

Quality

96%

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SecuritybySnyk

Low

Low-risk findings worth noting

SKILL.md
Quality
Evals
Security

Quality

Content

93%Weight 40%Scale 1-5

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

A high-quality body: token-efficient, gotcha-dense, and fully actionable, with an outstanding one-level-deep reference structure. The only gap is that the canonical service-creation workflow lives in the sibling fastly-cli skill rather than being sequenced inline in this skill.

DimensionReasoningScore

Conciseness

Lean and efficient for its density: ~165 lines cover an entire CDN platform's gotchas, recipes, navigation, and quick-start without explaining concepts Claude already knows; every prose line (Vary-header warning, subfield() false-match, ttl-suffix type error) earns its place by preventing a Fastly-specific silent failure.

5 / 5

Actionability

Fully executable, copy-paste-ready guidance throughout — concrete VCL recipes, `curl -sI -H "Host: ..."`, an `openssl s_client | x509` SAN check, and `table`/`table.lookup()` patterns cover the common cases directly.

5 / 5

Workflow Clarity

The Quick Start gives a clear pre-flight-validated sequence ('Verify the origin responds', 'Check TLS certificate SANs') before touching config, but the full create-service/add-domain/add-backend/activate workflow is deferred to the separate fastly-cli skill rather than shown inline with checkpoints here.

4 / 5

Progressive Disclosure

An exemplary Topics table maps every topic to a verified one-level-deep reference file with a 'Use when...' column, the overview body points to detailed materials, and all 20 referenced paths in references/ exist and resolve; navigation is trivial.

5 / 5

Total

19

/

20

Passed

Description

100%Weight 40%Scale 1-5

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

An exemplary description: third-person voice, concrete and comprehensive capability listing, explicit 'Use when...' triggers with natural troubleshooting phrasings, and a tightly bounded Fastly-specific niche with negligible conflict risk.

DimensionReasoningScore

Specificity

Lists multiple concrete capability areas — 'service and backend setup, caching and VCL, security features like DDoS/WAF/NGWAF/rate limiting/bot management, TLS certificates and cache purging, the Compute platform, and the REST API' — giving comprehensive coverage of what the skill does.

5 / 5

Completeness

Explicitly answers both what ('Configures, manages, and debugs the Fastly CDN platform — covering...') and when ('Use when working with Fastly services or domains... Also applies when troubleshooting 503 errors or SSL/TLS certificate mismatches...') with concrete trigger phrases.

5 / 5

Trigger Term Quality

Comprehensive natural trigger terms including synonyms and troubleshooting phrasings users would actually say — 'Fastly services or domains', 'edge caching', 'origin shielding', '503 errors', 'SSL/TLS certificate mismatches', 'logging endpoints', 'load balancing', 'ACLs', 'edge dictionaries'.

5 / 5

Distinctiveness Conflict Risk

A clear Fastly-only niche with distinct triggers ('Fastly', '503 errors on Fastly', 'SSL/TLS certificate mismatches on Fastly') and minimal conflict risk; the scope is tightly bounded to the Fastly CDN platform.

5 / 5

Total

20

/

20

Passed

Validation

100%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation16 / 16 Passed

Validation for skill structure

No warnings or errors.

Repository
fastly/fastly-agent-toolkit
Reviewed

Table of Contents

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