Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/fastly/fastly-agent-toolkit/viceroynpx skills add fastly/fastly-agent-toolkit --skill viceroygit clone --depth 1 https://github.com/fastly/fastly-agent-toolkitWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/fastly/fastly-agent-toolkit/viceroy)<a href="https://agentmods.dev/skills/fastly/fastly-agent-toolkit/viceroy"><img src="https://agentmods.dev/badge/skills/fastly/fastly-agent-toolkit/viceroy.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00132 | $0.00643 |
| Opus 5 | $0.00066 | $0.00321 |
| Sonnet 5 | $0.00026 | $0.00129 |
| Haiku 4.5 | $0.00013 | $0.00064 |
Grade A, and why
viceroy scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 43 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Viceroy — Local Fastly Compute Runtime
Viceroy is Fastly's official local testing environment for Compute applications. It emulates the Fastly Compute platform, allowing you to develop and test WASM services locally.
Viceroy documentation: https://github.com/fastly/Viceroy
Common Gotchas
- Dictionaries and ConfigStores are both supported but configured differently in
fastly.toml. Dictionaries go under[local_server.dictionaries]as inline key-value maps or JSON files. ConfigStores go under[local_server.config_stores]. fastly.tomlmust have a[local_server]section. Without it, Viceroy won't know about your backends, stores, or other local overrides. Every backend your app calls must be listed under[local_server.backends].- Default port is 7676, not 5000 (which is Fastlike's default). Access your app at
http://127.0.0.1:7676. - Backends should point to local servers when developing locally. Avoid proxying to remote production origins to prevent accidentally leaking request data.
Quick Start
# Install Viceroy
cargo install --locked viceroy
# Build your Compute app
fastly compute build
# Start local server (default: 127.0.0.1:7676)
viceroy -C fastly.toml bin/main.wasm
# Or use the Fastly CLI wrapper
fastly compute serve
References
| Topic | File | Use when... |
|---|---|---|
| Serve | fastly-compute-serve.md | Starting local dev server, profiling, advanced server options |
| Config | fastly-compute-config.md | Configuring fastly.toml backends, stores, geolocation, device detection, ACLs |
| Test | fastly-compute-test.md | Running Rust unit tests with cargo-nextest, writing tests for Compute services |
| Adapt | fastly-compute-adapt.md | Converting core WASM modules to Component Model, custom build pipelines |
What ships with it
4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 6d ago First seen · 43 lines · 132 tokens per session scan A e4c0c988bbec
viceroy is a skill published in the GitHub repository fastly/fastly-agent-toolkit (32 stars, last pushed 5d ago), licensed MIT. It adds 132 tokens to every session and 643 once invoked, about $0.0007 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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