Name: viceroy
Rating: 76 (1 reviews)
Author: fastly

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.

Quality

93%

Does it follow best practices?

Impact

—

No eval scenarios have been run

Securityby

Advisory

Suggest reviewing before use

Quality

Content

87%

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

This is a well-structured skill that efficiently communicates the essentials of using Viceroy for local Fastly Compute development. The gotchas section adds genuine value with non-obvious configuration details, and the progressive disclosure via the reference table is exemplary. The main weakness is the lack of validation/verification steps in the workflow, which would help catch common issues like misconfigured backends or failed builds.

Suggestions

Add a validation step after `viceroy -C fastly.toml bin/main.wasm`, such as `curl http://127.0.0.1:7676/` to verify the server is running and responding, with guidance on what to do if it fails (e.g., check fastly.toml has [local_server] section).

Dimension	Reasoning	Score
Conciseness	The content is lean and efficient. The introductory sentence is borderline unnecessary ('Viceroy is Fastly's official local testing environment...') but it's brief enough. The gotchas section provides genuinely useful, non-obvious information. No concepts are over-explained.	3 / 3
Actionability	The Quick Start provides fully executable, copy-paste-ready commands for installing, building, and running Viceroy. The gotchas section includes specific configuration paths (e.g., `[local_server.backends]`), port numbers, and concrete details that are immediately actionable.	3 / 3
Workflow Clarity	The Quick Start provides a clear sequence of steps for getting started, but there are no validation checkpoints or error recovery steps. For a tool that involves WASM compilation and local server configuration, a validation step (e.g., checking the server is running, verifying backend connectivity) would be valuable.	2 / 3
Progressive Disclosure	Excellent structure with a concise overview, gotchas, and quick start at the top level, then a well-organized reference table pointing to four clearly-described reference files. References are one level deep with clear 'Use when...' descriptions for navigation.	3 / 3
	Total	11 / 12 Passed

Description

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 hits all the marks. It provides highly specific concrete actions, includes abundant natural trigger terms that developers would use, explicitly states both what the skill does and when to use it, and even proactively distinguishes itself from a related skill to minimize conflict. The description is thorough without being padded, and uses proper third-person voice throughout.

Dimension	Reasoning	Score
Specificity	Lists multiple specific concrete actions: running WASM apps locally with Viceroy, configuring fastly.toml for backend overrides and store definitions, running Rust unit tests with cargo-nextest, debugging Compute apps, adapting core WASM modules to Component Model, and troubleshooting specific issues.	3 / 3
Completeness	Clearly answers both 'what' (runs Fastly Compute WASM apps locally with Viceroy for Rust/Component Model projects) and 'when' (explicit 'Use when...' clause listing six specific trigger scenarios). Also includes a helpful negative boundary directing users to the fastlike skill for non-Rust work.	3 / 3
Trigger Term Quality	Excellent coverage of natural terms users would say: 'Viceroy', 'Fastly Compute', 'WASM', 'Rust', 'Component Model', 'fastly.toml', 'cargo-nextest', 'local dev server', 'connection refused', 'missing backends', 'store config'. These are highly specific terms a developer would naturally use.	3 / 3
Distinctiveness Conflict Risk	Highly distinctive with a clear niche (Viceroy + Rust + Fastly Compute local development). The description even explicitly differentiates itself from a related 'fastlike' skill, reducing conflict risk. The combination of specific tools (Viceroy, cargo-nextest, fastly.toml) makes accidental triggering very unlikely.	3 / 3
	Total	12 / 12 Passed

Validation

100%

Warnings & errors only

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

Validation — 11 / 11 Passed

Validation for skill structure

No warnings or errors.

Repository: fastly/fastly-agent-toolkit
Commit: 73af5b9

Reviewed: 13 days ago

Table of Contents

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