Borrowing it
Nothing to install: this file belongs to mtnyilmaz/agents. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/mtnyilmaz/agents/main/.agents/skills/sast-businesslogic/SKILL.mdgit clone --depth 1 https://github.com/mtnyilmaz/agentsWrote 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/mtnyilmaz/agents/sast-businesslogic)<a href="https://agentmods.dev/skills/mtnyilmaz/agents/sast-businesslogic"><img src="https://agentmods.dev/badge/skills/mtnyilmaz/agents/sast-businesslogic/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/mtnyilmaz/agents/sast-businesslogic"><img src="https://agentmods.dev/badge/skills/mtnyilmaz/agents/sast-businesslogic.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 | $0.00104 | $0.03903 |
| Opus 5 | $0.00052 | $0.01951 |
| Sonnet 5 | $0.00021 | $0.00781 |
| Haiku 4.5 | $0.00010 | $0.00390 |
Grade A, and why
sast-businesslogic 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 11d 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.
> [Step-by-step instructions or curl commands to confirm the finding on the live app. How it starts
The opening of the file, as written. The whole thing — 327 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Business Logic Vulnerability Detection
You are performing a focused security assessment to find business logic vulnerabilities in a codebase. This skill uses a two-phase approach with subagents: threat modeling (understand the domain and generate attack scenarios) then verify (check whether those attack scenarios are exploitable).
Prerequisites: sast/architecture.md must exist. Run the analysis skill first if it doesn't.
What are Business Logic Vulnerabilities
Business logic vulnerabilities arise when an application's intended workflow, rules, or constraints can be manipulated to produce unintended outcomes — without exploiting technical flaws like injection or memory corruption. The attacker operates within the application's own features but uses them in ways the developers did not anticipate.
The core pattern: the application accepts input that is syntactically valid and passes authentication/authorization, but violates a business rule that was never enforced in code.
What Business Logic Vulnerabilities ARE
- Submitting a negative quantity to a purchase endpoint, receiving a credit instead of a charge
- Applying the same one-time discount coupon multiple times in parallel requests
- Skipping the payment step in a multi-step checkout by replaying a later step's request
- Posting a rating of 9999 to a movie rating endpoint that should cap ratings at 5
- Transferring a negative amount to move money from the recipient to the sender
- Redeeming a referral bonus by referring yourself with a second account
- Re-using a single-use reset token or voucher that was never invalidated
- Purchasing an item that is out of stock due to a race condition between inventory check and reservation
- Accessing a premium subscription feature after downgrading to a free plan
- Winning an auction by retracting a high bid after others have been eliminated
What Business Logic Vulnerabilities are NOT
Do not flag these as business logic issues:
- SQL injection, XSS, RCE, XXE, SSRF, SSTI: These are injection/technical flaws — separate skills cover them
- Missing authentication: Endpoint requires no login at all → that's "Unauthenticated Access"
- IDOR: Accessing another user's resource by changing an ID → that's a separate access-control class
- Brute-force / rate limiting: Generic rate-limit bypass on login → that's not a business logic flaw unless it enables specific business rule circumvention
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.
- 11d ago First seen · 327 lines · 104 tokens per session scan A 1f1e680fa22b
sast-businesslogic is a skill published in the GitHub repository mtnyilmaz/agents (6 stars, last pushed 3mo ago), licensed MIT. It adds 104 tokens to every session and 3,903 once invoked, about $0.0005 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 2026-08-31.
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