Code Intelligence Tools

Use Roslyn for C# structural questions. For other languages, use the built-in code intelligence, LSP, or search tools available in your environment.

Never use grep/glob/file reads for structural questions when Roslyn or the built-in tools can answer it faster.

Decision Rules

Use roslyn (dotnet-roslyn-mcp) when:

• The question involves C# code
• You need to find callers or callees of a C# method
• You need to find all implementations of a C# interface
• You need to find all references to a C# symbol
• You need accurate cross-file type resolution in C#
• You're assessing blast radius of a C# change

For non-C# languages:

• Use the built-in code intelligence, LSP, or search tools in your environment
• Fall back to rg, glob, and view for targeted inspection when needed

Common Workflows

Before planning a Medium/Large C# task:

1. roslyn:find_references on the C# symbol(s) you plan to change — blast radius
2. roslyn:find_implementations if changing a C# interface
3. Include results in the plan before implementing

"What calls X?" (C#) → roslyn:find_callers or roslyn:find_references

"Where is X implemented?" (C# interface) → roslyn:find_implementations

"Find all classes/functions matching a pattern" → roslyn:search_symbols (C# backend) → use your environment's built-in code intelligence or search tools for other languages

"What's the overall architecture?" → use your environment's built-in code intelligence or search tools

Setup

1. Install dotnet-roslyn-mcp (see setup.sh in the copilot-tools repo)
2. Copy this skill into your project's .github/skills/ directory:

   cp -r copilot-tools/skills/code-intelligence your-project/.github/skills/

3. Ensure your ~/.copilot/mcp-config.json has the Roslyn server entry (see templates/mcp-config.json)