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 wedabro/bro-skills --skill speckit.payment-fintechgit clone --depth 1 https://github.com/wedabro/bro-skillsWrote 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/wedabro/bro-skills/speckit.payment-fintech)<a href="https://agentmods.dev/skills/wedabro/bro-skills/speckit.payment-fintech"><img src="https://agentmods.dev/badge/skills/wedabro/bro-skills/speckit.payment-fintech/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/wedabro/bro-skills/speckit.payment-fintech"><img src="https://agentmods.dev/badge/skills/wedabro/bro-skills/speckit.payment-fintech.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 | $0.00031 | $0.00869 |
| Opus 5 | $0.00015 | $0.00434 |
| Sonnet 5 | $0.00006 | $0.00174 |
| Haiku 4.5 | $0.00003 | $0.00087 |
Grade A, and why
speckit.payment-fintech 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 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.
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 — 64 lines — stays where its author put it; the contents beside it link to each section on GitHub.
🎯 Mission
Architect and build zero-defect financial, payment, and ledger systems. Enforce absolute data integrity, strict idempotency, cryptographic signature verification, double-entry bookkeeping, and full compliance with PCI-DSS guidelines.
📥 Required Inputs
.agents/specs/[feature]/spec.md,plan.md, andtasks.md- Target payment gateways (Stripe, PayPal, ZaloPay, MoMo, VNPay, Bank Transfer)
- Currency, fee structures, refund policies, and regulatory requirements
📋 Protocol
1. Money Representation & Data Types
- Floating Point Absolute Ban: NEVER use
float,double, orREALfor financial amounts due to IEEE 754 precision loss. - Integer Standard: Store amounts in smallest currency units (e.g., cents for USD/EUR, single unit integer for VND/JPY).
- Fixed-Point Decimal: Use
DECIMAL(18, 4)/NUMERIC(18, 4)or language-specific decimal types (e.g. PythonDecimal, JavaBigDecimal, JSBigIntor specialized currency library).
2. Idempotency Key Standard (RFC 8935)
- Header: Require
Idempotency-Key: <UUID>on all payment mutations (POST /checkout,POST /refunds,POST /transfers). - Storage & Locking:
- Acquire atomic distributed lock on
idempotency:<user_id>:<key>in Redis. - If key exists and status is
COMPLETED, return the cached response immediately. - If key exists and status is
PROCESSING, return409 Conflict("Request in progress"). - Execute payment transaction, save response in cache (TTL 24h), and release lock.
- Acquire atomic distributed lock on
3. Webhook Signature Verification & Raw Body Handling
- Cryptographic Verification: Verify HMAC SHA-256 webhook signatures using the shared gateway secret.
- Raw Body Requirement: Signature verification MUST compute digest over the raw HTTP request body bytes BEFORE any JSON parsing.
- Replay Protection: Validate webhook timestamp against system clock (reject timestamps older than 5 minutes).
4. Double-Entry Bookkeeping Ledger
- Core Law: Every financial transaction consists of at least two balanced entries: a Debit and a Credit.
- Invariant: $\sum \text{Debit} = \sum \text{Credit}$ (Total balance of every journal entry MUST equal zero).
- Immutability: Ledger entries are append-only. NEVER update or delete a ledger row. Corrections MUST be made via offsetting Reversal / Adjustment entries.
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 · 64 lines · 31 tokens per session scan A 21cef847ad00
speckit.payment-fintech is a skill published in the GitHub repository wedabro/bro-skills (2 stars, last pushed 15d ago), licensed MIT. It adds 31 tokens to every session and 869 once invoked, about $0.0002 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.
Other skills, from other repositories
payments-intelligence-post-validate
Validate and cross-check BIN, IBAN, and SWIFT identifiers in one call. Returns per-field results and a consistency check that flags country and bank mismatches.
bin-lookup-get-{bin}
Returns card metadata for the given 6–8 digit BIN prefix.
commodities-get-{commodity}
Returns the latest annual average price and up to 10 years of historical data for the requested commodity slug.
inflation-get-inflation
Returns the latest annual CPI inflation rate for a country plus the previous 10 years of historical data.
inflation-post-batch
Returns inflation data for up to 50 countries in a single request. Results are in the same order as the input. Countries with no data return found: false instead of failing the whole request. Billing: 1 credit per country (not per HTTP request).
mortgage-get-mortgage
Returns the monthly payment, total cost, and full amortization schedule for a fixed-rate mortgage.