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 stagentic/stagentic-xdd --skill stage-02-subsections-examplesgit clone --depth 1 https://github.com/stagentic/stagentic-xddWrote 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/stagentic/stagentic-xdd/stage-02-subsections-examples)<a href="https://agentmods.dev/skills/stagentic/stagentic-xdd/stage-02-subsections-examples"><img src="https://agentmods.dev/badge/skills/stagentic/stagentic-xdd/stage-02-subsections-examples/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/stagentic/stagentic-xdd/stage-02-subsections-examples"><img src="https://agentmods.dev/badge/skills/stagentic/stagentic-xdd/stage-02-subsections-examples.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00020 | $0.00368 |
| Opus 5.5 | $0.00008 | $0.00147 |
| Sonnet 5.5 | $0.00004 | $0.00074 |
| Haiku 4.5 | $0.00002 | $0.00037 |
Grade A, and why
xdd 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 4d 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.
What it actually says
Apply the disciplines of TDD for adding or changing code overriding your understanding with the following principles:
Always write the test first
The test should always be written before the production code that makes it pass.
Failing for the right reason
A test fails for the right reason when it has an assertion failure where the actual result is not matching the expected result.
Making a test pass
Make a failing test pass using 'Fake-It' with 'Triangulation'; do not use 'Obvious Implementation'.
Fake-It
Fake-It makes a test pass by making the smallest possible change to the code that will pass the test, no matter how naive — and without breaking other tests. Use Fake-It as the default way to make a failing test pass.
For example, to pass a first test is_even(2) == True, return the literal True.
Triangulation
Triangulation is the process of each new test forcing an ever less naive implementation until the real implementation satisfies the desired capability.
For example, adding is_even(3) == False — which the return True fake-it implementation cannot pass —
forces the naive code towards the real return n % 2 == 0.
Obvious Implementation
Do not use Obvious Implementation. You can recognise it when you skip Fake-It and write the general implementation directly. Instead, use Fake-It, then Triangulation, to reach the real implementation.
For example, if you have a test asserting only is_even(2) == True then writing
return n % 2 == 0 is applying the Obvious Implementation strategy.
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.
- 4d ago First seen · 46 lines · 20 tokens per session scan A 3ab4aaedab20
xdd is a skill published in the GitHub repository stagentic/stagentic-xdd (5 stars, last pushed 4d ago), licensed MIT. It adds 20 tokens to every session and 368 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-09-26.
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