add_member

[refactoring]

Inserts a C# member into an existing type and returns a diff.

Before you use this tool

Writes files by default. Set applyChanges: false to preview the diff. Inspect the diff before application.

Parameters

Name	Type	Required	Description
containerName	string	Yes	The type to add the member to. A stable symbolKey (preferred) or a name (simple or fully qualified).
memberCode	string	Yes	The full C# source of the member to insert.
filePath	string	No	For a partial type, the file whose part receives the member. Absolute or loaded-root-relative. Defaults to the largest non-generated part.
projectName	string	No	Optional project name to limit search when finding the type by name.
applyChanges	boolean	No	If true (default), applies changes to disk. If false, returns a preview diff. Default: `true`
failOnErrors	boolean	No	If true, do not write when the edit introduces a compile error; the response reports the diagnostics. Default: `false`
includeDiff	boolean	No	Include unified diff in response. Default is true. Default: `true`
maxDiffChars	number	No	Max diff characters. Use 0 for unlimited. Default is 50000. Default: `50000`
includePerFileDiff	boolean	No	Include per-file diffs in changedFiles. Default is true. Default: `true`
pathStyle	string	No	Path style: 'absolute' (default) or 'relative' (to solution root). Default: `"absolute"`
responseDetail	string	No	compact returns results and actionable state. full adds diagnostic metadata under responseDiagnostics. Default: `"compact"`

Examples

Replace sample paths and symbol keys with values from your workspace.

Preview adding a method to a class

Arguments 
{
  "containerName": "OrderService",
  "memberCode": "public decimal Total() => 0m;",
  "applyChanges": false
}

Full MCP request

Full MCP request 
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "add_member",
    "arguments": {
      "containerName": "OrderService",
      "memberCode": "public decimal Total() => 0m;",
      "applyChanges": false
    }
  }
}

Illustrative response 
{
  "success": true,
  "containerName": "MyProject.OrderService",
  "memberName": "Total",
  "memberKind": "Method",
  "filePath": "/path/to/OrderService.cs",
  "filesChanged": 1,
  "applied": false,
  "message": null,
  "diagnostics": {
    "errorCount": 0,
    "warningCount": 0,
    "items": []
  },
  "unifiedDiff": "...",
  "changedFiles": [
    {
      "filePath": "/path/to/OrderService.cs",
      "changeCount": 1,
      "diff": "..."
    }
  ]
}

Preview insertion into a discovered type

Arguments 
{
  "containerName": "<type key from search_symbols>",
  "memberCode": "public decimal Total() => 0m;",
  "applyChanges": false
}

Full MCP request

Full MCP request 
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "add_member",
    "arguments": {
      "containerName": "<type key from search_symbols>",
      "memberCode": "public decimal Total() => 0m;",
      "applyChanges": false
    }
  }
}

Response Notes

The member text is parsed and validated before it is inserted, and only the inserted code is formatted, so the change lands indented in the body without reformatting the rest of the file. For a partial type, filePath chooses which part receives the member; by default the largest non-generated part is used.

Returns a unified diff of the insertion. containerName, memberName, and memberKind identify what was added, and filePath names the file that received it (the chosen part for a partial type). diagnostics reports the compile errors and warnings the inserted member introduces; when failOnErrors is true and it introduces an error, applied is false and message explains why. When the file is linked into several projects or targets, the check spans all of them. Results use top-level fields with success. Compact is the default; full adds responseDiagnostics. Both modes retain errors, coverage, partial state, and recovery advice.