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 AtlasOmnia/donna-starter --skill marketplace-purchase-vettinggit clone --depth 1 https://github.com/AtlasOmnia/donna-starterWrote 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/atlasomnia/donna-starter/marketplace-purchase-vetting)<a href="https://agentmods.dev/skills/atlasomnia/donna-starter/marketplace-purchase-vetting"><img src="https://agentmods.dev/badge/skills/atlasomnia/donna-starter/marketplace-purchase-vetting/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/atlasomnia/donna-starter/marketplace-purchase-vetting"><img src="https://agentmods.dev/badge/skills/atlasomnia/donna-starter/marketplace-purchase-vetting.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, 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 Excessive Agency · line 119 Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
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 | $0.00072 | $0.02547 |
| Opus 5 | $0.00036 | $0.01273 |
| Sonnet 5 | $0.00014 | $0.00509 |
| Haiku 4.5 | $0.00007 | $0.00255 |
Grade A, and why
marketplace-purchase-vetting 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 12d 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- marketplace-purchase-vetting — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 182 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Marketplace Purchase Vetting
Use this when the user asks whether a local listing is a scam, "too good to be true," worth looking at, or a good deal. Also use this when he asks you to find options — search/discover candidates, then vet the best ones. The goal is not a generic buying guide; it is a practical risk read with clear next steps.
Two modes: Discovery (find me options) and Vetting (check this listing). Run them in sequence when the user hasn't identified a specific listing.
Mode 1: Discovery — Search for candidates in the area
Run this first when the user says "find me a car/suv/truck for $X in our area" without a specific link. The output is a ranked shortlist of the best live options.
Facebook Marketplace search procedure
Read before a broad or tightly constrained vehicle hunt; it documents radius conversion, ignored filters, regional partitioning, feed virtualization, and dealer/down-payment traps.
- Set up the search URL. Facebook Marketplace uses structured URL parameters:
https://www.facebook.com/marketplace/{city}/vehicles?minPrice={min}&maxPrice={max}&sortBy=creation_time_descend&exact=false
- Default to the user's nearest metro area as the city slug; ask when unclear.
- Set price range with ~$500 buffer below max budget (e.g. $3,000--$4,000 for a $3.5k budget) so the floor filters out junk but the ceiling doesn't miss negotiable listings.
sortBy=creation_time_descendshows newest first — gives the freshest picks.
-
Navigate in a logged-in browser session. Facebook Marketplace requires authentication to show results. Use the browser tool (Chrome CDP). Navigate to the constructed URL.
-
Scrape the results page via CDP
Runtime.evaluate— much faster than clicking each listing:
JSON.stringify(Array.from(document.querySelectorAll(
'a[href*="/marketplace/item/"]'
)).map(a => ({
text: a.innerText.trim(),
url: (a.href.match(/marketplace\/item\/(\d+)/) || [])[1]
})).filter(x => x.text))
This returns all visible listings' title, price, location, item ID as one JSON blob.
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.
- 12d ago First seen · 182 lines · 72 tokens per session scan A 3aadf3f0c947
marketplace-purchase-vetting is a skill published in the GitHub repository AtlasOmnia/donna-starter (111 stars, last pushed 13d ago), licensed MIT. It adds 72 tokens to every session and 2,547 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 2026-08-30.
Other skills, from other repositories
marketplace-purchase-vetting
Use this when the user asks whether a local listing is a scam, "too good to be true," worth looking at, or a good deal. Also use this when he asks you to find options — search/discover candidates, then vet the best ones. The goal is not a generic buying guide; it is a practical risk read with clear next steps.
vc-finder
Takes a startup product URL or description, detects the industry and funding stage, identifies 5 comparable funded companies, searches who invested in those companies (Track A), finds VCs who publish investment theses about this space (Track B), and returns a ranked sourced list of relevant investors with deep-dives…
vc-curated-match
Accepts a product description and URL to algorithmically identify relevant Venture Capital investors targeting exactly that stage, industry, and niche based on a curated static dataset.
saas-billing
Implement and audit SaaS billing systems, subscription state machines, secure webhooks, and local database synchronization / Implementasi dan audit sistem billing SaaS, state machine langganan, webhook aman, dan sinkronisasi database lokal.
payment-gateway-expert
Expert guide for integrating payment gateways (Stripe, PayPal, Xendit, Midtrans, DOKU) and secure webhooks into SaaS platforms / Panduan ahli integrasi payment gateway dan webhook aman.
szamlazzhu-document-xml-compatibility
Integrate another WooCommerce plugin with Integration for Szamlazz.hu & WooCommerce document generation. Covers WCSzamlazz()->generateinvoice(), wcszamlazzxml, wcszamlazzinvoicelineitem, wcszamlazzbeforegenerateinvoicecheck, document meta, Action Scheduler deferral, Pro webhooks/IPN including HPOS-safe custom…