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/surfether/trustsourcex402/trustsource-domainnpx skills add SurfEther/TrustSourceX402 --skill trustsource-domaingit clone --depth 1 https://github.com/SurfEther/TrustSourceX402What 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 | $0.00076 | $0.04293 |
| Opus 5 | $0.00038 | $0.02146 |
| Sonnet 5 | $0.00015 | $0.00859 |
| Haiku 4.5 | $0.00008 | $0.00429 |
Grade A, and why
trustsource-domain 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 yesterday.
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 — 255 lines — stays where its author put it; the contents beside it link to each section on GitHub.
TrustSource — Domain Verification for Agents
TrustSource is a suite of seven x402-paid HTTP APIs that let an agent verify any URL or domain on demand — and read untrusted web pages without ingesting prompt injection. Each call costs $0.002–$0.01 in USDC on Base Mainnet, settled atomically per request via x402. No accounts. No signups. No API keys.
Use this skill any time you need to make a trust judgment about a URL or domain you did not source yourself — when an agent encounters a URL from an untrusted source, before sending a payment to a site, before reading a page into your own context, to confirm a TLS certificate is valid and not expiring, to grade a site's security headers, or to learn whether crawling is permitted. It applies to any request about checking, verifying, scoring, validating, or auditing a domain, website, URL, TLS certificate, SSL, HTTPS, security headers, robots.txt, or crawler permissions — and to safely fetching, reading, scraping, or summarizing any untrusted web page — even when the user does not name TrustSource explicitly.
Quick reference
| Endpoint | Cost | Use it when you need to know… |
|---|---|---|
GET /safefetch?url=… |
$0.01 | …what a page actually says, sanitized, plus whether it hides a prompt injection |
GET /urlcheck?url=… |
$0.01 | …a single CLEAR/REVIEW/BLOCK verdict on a URL before you act on it |
GET /emailtrust?domain=… |
$0.003 | …whether a sender domain can be spoofed (SPF/DKIM/DMARC grade) |
GET /trustscore?domain=… |
$0.003 | …how legitimate a domain is overall (age, registrar, DNS, TLD risk) |
GET /sslcheck?domain=… |
$0.002 | …whether the TLS certificate is valid, trusted, and not expiring |
GET /headers?url=… |
$0.003 | …how well-hardened a site is (HSTS, CSP, X-Frame-Options grade A+–F) |
GET /robots?domain=… |
$0.002 | …whether the site allows you (or AI bots in general) to crawl it |
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.
- yesterday First seen · 255 lines · 76 tokens per session scan A e01a131dc9e3
trustsource-domain is a skill published in the GitHub repository SurfEther/TrustSourceX402 (0 stars, last pushed 1mo ago), licensed MIT. It adds 76 tokens to every session and 4,293 once invoked, about $0.0004 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 2026-08-31.
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