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 skills add fastly/fastly-agent-toolkit --skill fastly-fiddlegit 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/fastly-fiddle)<a href="https://agentmods.dev/skills/fastly/fastly-agent-toolkit/fastly-fiddle"><img src="https://agentmods.dev/badge/skills/fastly/fastly-agent-toolkit/fastly-fiddle.svg" alt="Measured on agentmods" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 2 findings, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Data Exfiltration · line 42 Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
- medium Data Exfiltration · line 87 Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
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 | $0.00066 | $0.04046 |
| Opus 5 | $0.00033 | $0.02023 |
| Sonnet 5 | $0.00013 | $0.00809 |
| Haiku 4.5 | $0.00007 | $0.00405 |
Grade A, and why
fastly-fiddle scanned grade A with 1 finding 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 8d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
a `curl --data` argument and lose it when the call blocks. How it starts
The opening of the file, as written. The whole thing — 188 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Fastly Fiddle — Real-Edge VCL Testing
Trigger and scope
Trigger on: Fastly Fiddle, fiddle.fastly.dev URLs, the Fiddle HTTP API, CI testing of VCL services, real-edge VCL tests, shareable VCL reproductions, clientFetch.*/events.*/originFetches.* test expressions, .test.js / Mocha specs that target fiddles, SSE updateResult / waitingForSync events, remote VCL linting via Fiddle, or validating real Fastly behavior (geo, WAF, ESI, clustering, shielding) that local tools cannot simulate.
Do NOT use for: local VCL unit testing (use falco), fast TDD loops (Fiddle has a 10-20s edge-sync floor per publish), Fastly Compute/Wasm testing (use viceroy or fastlike), production service deployment (use fastly-cli), or anything requiring authenticated Fastly API access — Fiddle does not use your Fastly API key.
Fastly Fiddle is a web-based sandbox at https://fiddle.fastly.dev that compiles and runs VCL on real Fastly edge nodes. Because it uses the production VCL compiler and real POPs, it's the only way outside a real service to test VCL features that depend on edge infrastructure — geolocation data, WAF, ESI, clustering, shielding, rate limiting, real TLS, and real cache behavior.
Official UI: https://fiddle.fastly.dev
Demo CI runner: https://github.com/fastly/demo-fiddle-ci
API base: https://fiddle.fastly.dev (undocumented but stable; no auth required for public fiddles)
When Fiddle, when Falco
| Need | Use |
|---|---|
| Fast local iteration (< 1s), watch mode, offline | falco test |
| Real Fastly VCL compiler and semantics | Fiddle |
Real client.geo.*, WAF, ESI, rate limiting, shield |
Fiddle |
| Shareable URL for bug repros and support tickets | Fiddle |
| CI against real edge nodes | Fiddle |
| Structured lint with line/col (no execution required) | Either |
| Fastly Compute (WASM) | Neither — use viceroy/fastlike |
What ships with it
6 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.
- 8d ago First seen · 188 lines · 66 tokens per session scan A 9fd3e559945a
fastly-fiddle is a skill published in the GitHub repository fastly/fastly-agent-toolkit (32 stars, last pushed 7d ago), licensed MIT. It adds 66 tokens to every session and 4,046 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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