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.
git clone --depth 1 https://github.com/GoranErhartic/cursor-development-rulesWrote 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/rules/goranerhartic/cursor-development-rules/bff-architecture)<a href="https://agentmods.dev/rules/goranerhartic/cursor-development-rules/bff-architecture"><img src="https://agentmods.dev/badge/rules/goranerhartic/cursor-development-rules/bff-architecture/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/rules/goranerhartic/cursor-development-rules/bff-architecture"><img src="https://agentmods.dev/badge/rules/goranerhartic/cursor-development-rules/bff-architecture.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 | $0.03756 |
| Opus 5.5 | $0.00008 | $0.01502 |
| Sonnet 5.5 | $0.00004 | $0.00751 |
| Haiku 4.5 | $0.00002 | $0.00376 |
Grade A, and why
bff-architecture 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 2mo 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 — 260 lines — stays where its author put it; the contents beside it link to each section on GitHub.
BFF Architecture Patterns
What is a BFF?
A Backend-For-Frontend (BFF) is a service layer that sits between a client application and backend microservices. It:
- Aggregates data from multiple backend APIs
- Transforms backend responses to client-specific formats
- Handles authentication token pass-through or exchange
- Provides client-optimized endpoints
- Shields frontend from backend complexity
Architecture Overview
This BFF follows Clean Architecture combined with CQRS and Vertical Slice Architecture.
┌─────────────────────────────────────────────────────────────────────â”
│ WEB │
│ Controllers, Request/Response DTOs, Exception Handlers │
│ (Composition root - may access all inner layers) │
├─────────────────────────────────────────────────────────────────────┤
│ INFRASTRUCTURE │
│ HTTP Clients, Adapters, Filters, Interceptors, Config │
│ (Implements Application ports) │
├─────────────────────────────────────────────────────────────────────┤
│ APPLICATION │
│ CQRS Handlers, Ports (interfaces), Feature DTOs │
│ (Depends only on Domain) │
├─────────────────────────────────────────────────────────────────────┤
│ DOMAIN │
│ Core entities, Value objects, Errors, Enums │
│ (No external dependencies - framework agnostic) │
└─────────────────────────────────────────────────────────────────────┘
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.
- 2mo ago First seen · 260 lines · 20 tokens per session scan A eea78fe76daa
bff-architecture is a cursor rule published in the GitHub repository GoranErhartic/cursor-development-rules (19 stars, last pushed 8mo ago), licensed MIT. It adds 20 tokens to every session and 3,756 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 2026-08-30.
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