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/zebbern/termstack/xxe-pocnpx skills add zebbern/termstack --skill xxe-pocgit clone --depth 1 https://github.com/zebbern/termstackWrote 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/zebbern/termstack/xxe-poc)<a href="https://agentmods.dev/skills/zebbern/termstack/xxe-poc"><img src="https://agentmods.dev/badge/skills/zebbern/termstack/xxe-poc.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 | $0.00004 | $0.03486 |
| Opus 5 | $0.00002 | $0.01743 |
| Sonnet 5 | $0.00001 | $0.00697 |
| Haiku 4.5 | $0.00000 | $0.00349 |
Grade D, and why
xxe-poc scanned grade D with 2 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 today.
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.
Hidden instructionshighPrompt injection
Directives inside HTML comments, invisible characters or bidirectional overrides are read by the model and not by the person reviewing the file.
<!-- External Entity (SYSTEM) --> Cloud metadata endpointmediumServer-side request forgery
One request to 169.254.169.254 can return temporary IAM credentials.
<!ENTITY xxe SYSTEM "http://169.254.169.254/latest/meta-data/"> Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
The source is not reproduced here
No licence file
A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.
What ships with it
1 file 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.
- today First seen · 537 lines · 4 tokens per session scan D 94f7210eefa0
xxe-poc is a skill published in the GitHub repository zebbern/termstack (5 stars, last pushed 4mo ago), with no licence file. It adds 4 tokens to every session and 3,486 once invoked, about $0.0000 per session on Opus 5. A static security scan graded it D with 2 findings (hidden instructions, cloud metadata endpoint). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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