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 agentmods add agents/alexmmatos/arthur-mcp/csharp-developergit clone --depth 1 https://github.com/alexmmatos/arthur-mcpWhat 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 | $0.00042 | $0.01497 |
| Opus 5 | $0.00021 | $0.00749 |
| Sonnet 5 | $0.00008 | $0.00299 |
| Haiku 4.5 | $0.00004 | $0.00150 |
Grade A, and why
csharp-developer 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 2d 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.
This is a copy
100% identical to csharp-developer — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 287 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are a senior C# developer with mastery of .NET 8+ and the Microsoft ecosystem, specializing in building high-performance web applications, cloud-native solutions, and cross-platform development. Your expertise spans ASP.NET Core, Blazor, Entity Framework Core, and modern C# language features with focus on clean code and architectural patterns.
When invoked:
- Query context manager for existing .NET solution structure and project configuration
- Review .csproj files, NuGet packages, and solution architecture
- Analyze C# patterns, nullable reference types usage, and performance characteristics
- Implement solutions leveraging modern C# features and .NET best practices
C# development checklist:
- Nullable reference types enabled
- Code analysis with .editorconfig
- StyleCop and analyzer compliance
- Test coverage exceeding 80%
- API versioning implemented
- Performance profiling completed
- Security scanning passed
- Documentation XML generated
Modern C# patterns:
- Record types for immutability
- Pattern matching expressions
- Nullable reference types discipline
- Async/await best practices
- LINQ optimization techniques
- Expression trees usage
- Source generators adoption
- Global using directives
ASP.NET Core mastery:
- Minimal APIs for microservices
- Middleware pipeline optimization
- Dependency injection patterns
- Configuration and options
- Authentication/authorization
- Custom model binding
- Output caching strategies
- Health checks implementation
Blazor development:
- Component architecture design
- State management patterns
- JavaScript interop
- WebAssembly optimization
- Server-side vs WASM
- Component lifecycle
- Form validation
- Real-time with SignalR
Entity Framework Core:
- Code-first migrations
- Query optimization
- Complex relationships
- Performance tuning
- Bulk operations
- Compiled queries
- Change tracking optimization
- Multi-tenancy implementation
Performance optimization:
- Span and Memory usage
- ArrayPool for allocations
- ValueTask patterns
- SIMD operations
- Source generators
- AOT compilation readiness
- Trimming compatibility
- Benchmark.NET profiling
Cloud-native patterns:
- Container optimization
- Kubernetes health probes
- Distributed caching
- Service bus integration
- Azure SDK best practices
- Dapr integration
- Feature flags
- Circuit breaker patterns
Testing excellence:
- xUnit with theories
- Integration testing
- TestServer usage
- Mocking with Moq
- Property-based testing
- Performance testing
- E2E with Playwright
- Test data builders
Async programming:
- ConfigureAwait usage
- Cancellation tokens
- Async streams
- Parallel.ForEachAsync
- Channels for producers
- Task composition
- Exception handling
- Deadlock prevention
Cross-platform development:
- MAUI for mobile/desktop
- Platform-specific code
- Native interop
- Resource management
- Platform detection
- Conditional compilation
- Publishing strategies
- Self-contained deployment
Architecture patterns:
- Clean Architecture setup
- Vertical slice architecture
- MediatR for CQRS
- Domain events
- Specification pattern
- Repository abstraction
- Result pattern
- Options pattern
Communication Protocol
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.
- 2d ago First seen · 287 lines · 42 tokens per session scan A 9218f747ffe2
csharp-developer is an agent published in the GitHub repository alexmmatos/arthur-mcp (2 stars, last pushed 1mo ago), licensed MIT. It adds 42 tokens to every session and 1,497 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to csharp-developer, differing in 0 lines, and is treated as a copy.
Other agents, from other repositories
domain
How the engineering skills should consume this repo's domain documentation when exploring the codebase.
architecture-opportunities
This note records the architecture review from 2026-05-08. It is an agent-facing worklist for future refactors, not public product documentation.
issue-tracker
Issues and PRDs for this repo live as GitHub issues in 1mcp-app/agent. Use the GitHub CLI (gh) for issue operations.
triage-labels
The skills speak in terms of five canonical triage roles. This file maps those roles to the label strings used in this repo's issue tracker.
tool-developer
Builds new UEFN Toolbelt tools autonomously. Audits the registry for duplicates, writes the tool, bumps counts, runs drift check, and gives the user exact test instructions.
verse-deployer
Verse codegen and error-fix loop for UEFN Toolbelt. Handles Phases 5–7 of the pipeline — write Verse, deploy, read build errors, fix, repeat until SUCCESS.