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viceroy

Runs Fastly Compute WASM applications locally with Viceroy, specifically for Rust and Component Model projects. Use when starting a local Fastly Compute dev server with Viceroy, configuring fastly.toml for local backend overrides and store definitions, running Rust unit tests with cargo-nextest against the Compute runtime, debugging Compute apps locally, adapting core WASM modules to the Component Model, or troubleshooting local Compute testing issues (connection refused, missing backends, store config). For non-Rust Compute work or understanding the Compute API, prefer the fastlike skill instead — its source code is easier to understand as a Fastly Compute API reference.

77

Quality

96%

Does it follow best practices?

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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 well-structured, token-efficient body that leads with non-obvious gotchas and executable commands, then defers detail to four real, well-labeled reference files. The only minor gap is an explicit verification checkpoint after starting the dev server.

Suggestions

Add an explicit verification step after 'viceroy -C fastly.toml bin/main.wasm' (e.g., curl http://127.0.0.1:7676/ and expect a response) so the workflow has a concrete success checkpoint.

Note one or two common serve-time failure modes inline (e.g., missing [local_server] section error text) with the fix, since troubleshooting is a stated trigger but lives only in the references.

DimensionReasoningScore

Conciseness

The body is lean: a one-line intro, four high-value gotchas Claude would not already know (port 7676 vs 5000, the [local_server] requirement, dictionaries vs config_stores placement, avoid proxying to production), and a compact quick-start — no padding or explanation of basic concepts.

5 / 5

Actionability

Quick start provides copy-paste ready, executable commands ('cargo install --locked viceroy', 'fastly compute build', 'viceroy -C fastly.toml bin/main.wasm', 'fastly compute serve') and the gotchas give specific config directives that cover the common cases.

5 / 5

Workflow Clarity

The install → build → serve sequence is clear and the port note doubles as an implicit verification signal, but there is no explicit 'confirm the server is reachable' checkpoint or error-recovery loop for the serve step.

4 / 5

Progressive Disclosure

SKILL.md is a well-organized overview with clearly signaled one-level-deep references: a References table maps each of the four existing reference files to a 'Use when...' column, all of which resolve to real files in ./references/.

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.

A strong description that answers what and when with concrete, natural trigger phrases and a clear niche. It even includes proactive boundary guidance against a sibling skill, which is above typical quality.

DimensionReasoningScore

Specificity

Lists multiple concrete actions — 'starting a local Fastly Compute dev server', 'configuring fastly.toml for local backend overrides and store definitions', 'running Rust unit tests with cargo-nextest', 'adapting core WASM modules to the Component Model', 'troubleshooting local Compute testing issues (connection refused, missing backends, store config)' — giving comprehensive coverage rather than generic verbs.

5 / 5

Completeness

Explicitly states what it does ('Runs Fastly Compute WASM applications locally with Viceroy, specifically for Rust and Component Model projects') and provides a concrete 'Use when...' clause enumerating multiple trigger scenarios.

5 / 5

Trigger Term Quality

Covers natural user phrases including error signals users actually say ('connection refused', 'missing backends', 'store config'), file names ('fastly.toml'), and tooling ('cargo-nextest', 'dev server'), spanning synonyms and concrete artifacts.

5 / 5

Distinctiveness Conflict Risk

Carves a clear niche (Rust + Component Model + Viceroy local runtime) and explicitly routes conflicting cases elsewhere — 'For non-Rust Compute work or understanding the Compute API, prefer the fastlike skill instead' — minimizing wrong-skill triggering.

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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