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/csharp-dotnet)<a href="https://agentmods.dev/rules/goranerhartic/cursor-development-rules/csharp-dotnet"><img src="https://agentmods.dev/badge/rules/goranerhartic/cursor-development-rules/csharp-dotnet/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/csharp-dotnet"><img src="https://agentmods.dev/badge/rules/goranerhartic/cursor-development-rules/csharp-dotnet.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 | $0.00000 | $0.00723 |
| Opus 5.5 | $0.00000 | $0.00289 |
| Sonnet 5.5 | $0.00000 | $0.00145 |
| Haiku 4.5 | $0.00000 | $0.00072 |
Grade A, and why
csharp-dotnet 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 1mo 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 — 67 lines — stays where its author put it; the contents beside it link to each section on GitHub.
C# + .NET Development Guide
Stack
| Layer | Technology |
|---|---|
| Runtime | .NET 10 |
| Framework | ASP.NET Core |
| Validation | FluentValidation |
| Data | Entity Framework Core |
| Messaging | Rebus |
| Resilience | Polly |
| Testing | xUnit, FluentAssertions, Moq, Testcontainers |
| Logging | Serilog |
Rule Routing
Consult these rules based on what you are working on:
Quick Reference
- Build/modify API endpoint:
languages/csharp/controllers.mdc,languages/csharp/validation.mdc,languages/csharp/error-handling.mdc - Build command/query flow:
languages/csharp/mediator.mdc,languages/csharp/testing.mdc - Data and transactions:
languages/csharp/ef-core.mdc,languages/csharp/resilience.mdc - Secure/auth changes:
languages/csharp/security.mdc,languages/csharp/auth.mdc,languages/csharp/input-sanitization.mdc
API & Controllers
- Controller conventions, routing, ActionResult →
languages/csharp/controllers.mdc - Request validation (FluentValidation) →
languages/csharp/validation.mdc - Input sanitization (SQL injection, XSS, path traversal) →
languages/csharp/input-sanitization.mdc
Data & Persistence
- EF Core DbContext, repositories, migrations →
languages/csharp/ef-core.mdc
CQRS & Messaging
- Mediator pattern (commands, queries, pipeline behaviors) →
languages/csharp/mediator.mdc - Rebus messaging (handlers, sagas, outbox) →
languages/csharp/messaging.mdc
Cross-Cutting
- Code quality, C# 14 idioms, records, nullable references →
languages/csharp/code-quality.mdc - Error handling (ProblemDetails, Result pattern) →
languages/csharp/error-handling.mdc - Logging (Serilog, enrichers, correlation IDs) →
languages/csharp/logging.mdc - Security (secrets, HTTPS, headers, CORS) →
languages/csharp/security.mdc - Auth (JWT Bearer, policy-based, claims) →
languages/csharp/auth.mdc - Resilience (Polly retry, circuit breaker, timeout) →
languages/csharp/resilience.mdc - Testing (xUnit, FluentAssertions, Moq) →
languages/csharp/testing.mdc - Dependencies (NuGet, Central Package Management) →
languages/csharp/dependencies.mdc
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.
- 1mo ago First seen · 67 lines · 0 tokens per session scan A 9331a7f12675
csharp-dotnet is a cursor rule published in the GitHub repository GoranErhartic/cursor-development-rules (19 stars, last pushed 7mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 723 tokens. 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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