What is dev-dotnet-backend-engineer?

A set of instructions for building server-side applications with .NET and C#, Microsoft's tools for creating web services and APIs. It covers common structures such as Clean Architecture, where code is separated by responsibility, and CQRS, where reading and changing data use separate paths.

Use it when adding ASP.NET endpoints, services, dependency injection, database migrations, data models, or performance and reliability improvements.

It helps keep backend changes consistent with the project's existing structure, data access rules, error handling, and testing practices.

dev-dotnet-backend-engineer — Skill for Claude Code by ThiagoGuislotti

Install

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.

Any agent

npx skills add ThiagoGuislotti/copilot-instructions --skill dev-dotnet-backend-engineer

Clone the repo

git clone --depth 1 https://github.com/ThiagoGuislotti/copilot-instructions

Made for: Claude Code.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/thiagoguislotti/copilot-instructions/dev-dotnet-backend-engineer.svg)](https://agentmods.dev/skills/thiagoguislotti/copilot-instructions/dev-dotnet-backend-engineer)

Your own site

<a href="https://agentmods.dev/skills/thiagoguislotti/copilot-instructions/dev-dotnet-backend-engineer"><img src="https://agentmods.dev/badge/skills/thiagoguislotti/copilot-instructions/dev-dotnet-backend-engineer.svg" alt="Measured on agentmods" height="20"></a>

Per session 64 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 373 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

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	$0.00064	$0.00373
Opus 5	$0.00032	$0.00187
Sonnet 5	$0.00013	$0.00075
Haiku 4.5	$0.00006	$0.00037

Measured 6d ago against content hash dfac93acb6e0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

dev-dotnet-backend-engineer 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 6d 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.

.claude/skills/dev-dotnet-backend-engineer/SKILL.md · 48 lines

What it actually says

Dev Dotnet Backend Engineer

Inherit from base skill

Load .claude/skills/dev-software-engineer/SKILL.md as the base contract.
Restrict domain scope to .NET backend, database, and ORM concerns only.

Domain instruction delta

.github/instructions/dotnet-csharp.instructions.md
.github/instructions/clean-architecture-code.instructions.md
.github/instructions/backend.instructions.md
.github/instructions/database.instructions.md
.github/instructions/orm.instructions.md
.github/instructions/microservices-performance.instructions.md (when applicable)

Claude-native execution

Run as a general-purpose agent within the Super Agent pipeline.

Execution workflow delta

Confirm layer boundaries and domain model ownership.
Implement minimal backend change preserving contracts.
Apply validation, error model, and observability patterns.
Add/update unit and integration tests for changed behavior.
Run targeted validation before claiming completion.

Prompt accelerators

.github/prompts/create-dotnet-class.prompt.md
.github/prompts/create-api-endpoint.prompt.md
.github/prompts/create-ef-migration.prompt.md
.github/prompts/refactor-to-clean-architecture.prompt.md

Validation examples

dotnet build
dotnet test --filter "Category=Unit"
dotnet test --filter "Category=Integration"
dotnet pack -c Release

Changes

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.

6d ago First seen · 48 lines · 64 tokens per session scan A dfac93acb6e0

Subscribe to this mod's changes

dev-dotnet-backend-engineer is a skill published in the GitHub repository ThiagoGuislotti/copilot-instructions (2 stars, last pushed 2mo ago), licensed MIT. It adds 64 tokens to every session and 373 once invoked, about $0.0003 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.

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