codeguard-csharp

C# Codeguard Gate

Goal: turn "looks fine" into reproducible tool evidence, and honestly distinguish between passed, failed, unverifiable, and planned.

30-Second Start

1. At the repository root, confirm that 无专用标记文件 or the target file exists.
2. Detect tools:dotnet --version。
3. First, do a read-only check:dotnet format --verify-no-changes。
4. Classify results as: code violations, missing configuration, missing tools, tool internal errors.
5. Only perform actions on safely fixable items:dotnet format。
6. Re-run lint, and run the project's existing test/build gates.

You can directly ask:

• "Check this C# project, don't modify anything yet, and give me a classification of lint failures."
• "Only fix C# formatting issues; list semantic issues first."
• "Verify C# lint, test, and build evidence before committing."

Capability Boundaries

✅ Good at handling

1. Based on .cs and project markers to identify the C# workspace.
2. Run dotnet format --verify-no-changes and retain the exit code, scope, and tool version.
3. Distinguish between formatting, static rules, configuration, dependency, and environment-related failures.
4. Use dotnet format to handle reversible issues and rescan.
5. Report local results in layers alongside CI/build/test evidence.

⚠️ Requires conditions

1. The target tool must already be installed and its version compatible with the project constraints.
2. It must be run from the correct repository or module root directory.
3. If the project has custom configuration, the committed configuration takes precedence.
4. Whether generated code, vendor, and cache directories are scanned must follow repository rules.

❌ Not applicable

1. Do not treat formatter passing as passing compilation, tests, or security audits.
2. Do not silently install tools, upgrade dependencies, or modify team rules.
3. Do not use suppress/ignore/raising thresholds to conceal real problems.
4. Do not claim "checks passed" when tools or configuration are missing.

When to use

• The user requests checking or fixing C# code style.
• AI modified .cs, and pre-commit verification is needed.
• CI has failures related to dotnet format --verify-no-changes .
• Need to determine whether an issue can be fixed automatically or must be handled manually.

When not to use

• When the main task is learning language syntax, framework design, or business modeling, use the corresponding language professional skill instead.
• When the main task is dependency vulnerabilities, security auditing, or license governance, use a dedicated security skill.
• When the user only asks to explain an error and there is no project context, provide a local explanation first and do not claim the repository is all green.

Data and Security

This skill does not collect, upload, send, or store user code and credentials. By default, it only reads local repository configuration and runs local tools; it does not install dependencies over the network and does not record tokens, passwords, or private source code. Before any automatic fix, check the diff first; destructive or large-scale changes must be explicitly confirmed by the user.

Execution Contract

Project	Current Facts
Status	stable(Since Codeguard V0.2)
File Extensions	.cs
Project Marker	No dedicated marker file
Integration Configuration	*.sln, *.csproj
Tool Preparation	.NET SDK 6+
Probe Command	使用命令查找与项目配置检查
lint	dotnet format --verify-no-changes
format/fix	dotnet format
Project-level gate	dotnet format --verify-no-changes

Standard Workflow

Step 1: Determine the real scope

Confirm the repository root, module roots, generated directories, vendor directories, and user-specified files. For multi-module projects, first list the modules that will be scanned; do not guess based on the current directory.

Step 2: Read the project contract

Read *.sln, *.csproj and the actual commands in CI. Repository configuration takes precedence over the examples in this skill; if the two conflict, report the difference first.

Step 3: Probe tools and versions

Run 对应工具 --version. Missing tools, incompatible versions, or configuration that cannot be loaded are all recorded as "Unable to verify", not as passing.

Step 4: Run read-only checks

Run dotnet format --verify-no-changes, and record the command, working directory, exit code, tool version, and the first actionable error.

Step 5: Classify failures

Type	Typical Signal	Handling
Formatting	Indentation, whitespace, import order	Formatter allowed, then check the diff
Static rules	unused, complexity, naming, dangerous API	Minimal semantic fix, no bulk guessing
Configuration	parser/config/schema not found	Fix the integration or report the prerequisites
Environment	command not found, version conflict	Report installation/version requirements, do not silently install
Internal tool error	crash, timeout, parser exception	Preserve the original evidence, narrow the reproduction scope

Step 6: Controlled fixes

Prefer to run dotnet format. Only handle issues that are certain and reversible; dependency upgrades, rule exemptions, generated files, and business semantic changes must be explained separately.

Step 7: Verification loop

Re-run the same lint command, then run the project's existing tests and build. Write "pass" only when the command, scope, and exit code are all clear; otherwise write "not run" or "unable to verify".

Rules

1. Re-verify with the same command: After fixing, you must re-run the original command that triggered the failure.
2. Layered evidence: Report lint, format, compile, test, and security separately.
3. Minimal changes: Do not refactor along the way, and do not expand style fixes into business rewrites.
4. Configuration first: Do not override the project's existing ignore, dialect, target, or version constraints.
5. No making things up: Tools not run, configurations not seen, and platforms not verified must be clearly labeled.

Output Template

C# Codeguard 结果
- 范围：<仓库/模块/文件>
- 工具：<名称与版本>
- 命令：<实际命令>
- 状态：PASS / FAIL / UNVERIFIED / PLANNED
- 发现：<按格式/规则/配置/环境分类>
- 修改：<文件与原因；无修改写 none>
- 复验：<命令、退出码>
- 未验证：<测试/构建/平台差异>

Gotchas

1. Missing tools are not passing — must output UNVERIFIED and a clear preparation method.
2. formatter is not linter — all-green formatting cannot cover static rules or compilation errors.
3. The root directory determines the result — Running in the wrong module may miss detection or load the wrong configuration.
4. Placeholders are not literal arguments — {file} must be replaced with real, authorized paths.
5. Automatic fixes may expand the diff — After fixing, review the diff first, then run the regression gate.
6. Generated and vendor directories require an explicit policy — Do not arbitrarily scan or modify third-party content across the whole repository.

Domain Pitfalls and Fixes

1. Project configuration takes precedence — Tool defaults must not override rules and version constraints already committed to the repository.

When information is insufficient

Do not just say "please provide more information." First give a safe read-only inspection plan, and list the specific items that still need confirmation:

1. Repository/module root directory;
2. Target tool and version;
3. Project configuration file;
4. Authoritative command in CI;
5. Whether automatic fixes are allowed.

FAQ

Q1: If the tool is not installed, can we conclude the code is fine? No. The status must be UNVERIFIED。

Q2: Can ignore or suppression be added automatically? No. Exemptions may only be granted when the user explicitly accepts them and the reason is recorded.

Q3: Why does it still fail after formatting? The formatter only covers formatting; static rules, configuration, compilation, and tests still need to be handled separately.

Q4: Should generated code be scanned? By default, follow the repository configuration; if there are no rules, exclude generated/vendor first, then explain to the user.

Q5: How can I avoid changing too much at once? First fix in batches by failure category and file, rerunning the original command and reviewing the diff for each batch.

Q6: If it passes locally, can I say CI will pass? No. You also need to align with CI's versions, environment variables, operating system, and command scope.

Load Resources on Demand

• When encountering exit codes, failure classifications, or exemption decisions, read references/rules/gate-rules.md。
• When you need to verify this language's registry, toolchain, and project configuration, read references/tooling/toolchain.md。
• When you need copyable task examples, read by scenario examples/, and there is no need to load everything at once.