[external]
Views source code for external symbols (NuGet/framework), via SourceLink or decompilation.
Framework and package behavior often explains local code, but the source is outside the repo.
The model can inspect external definitions and package usage evidence instead of guessing from API names.
Try it locally in the Glider playground
| Name | Type | Required | Description |
|---|---|---|---|
| symbolName | string | Yes | Symbol to look up: a simple name, a fully qualified type, or Type.Member ('...JsonSerializer.Serialize'). A Type.Member name returns the containing type anchored at the member, including a non-public one. |
| assemblyHint | string | No | Optional assembly name hint. It orders the search when the same type name exists in several assemblies, and never excludes an assembly, so a wrong hint costs position and not the result. |
| projectName | string | No | Optional project name to limit referenced assemblies. |
| maxLines | number | No | Maximum number of source lines to return. Use 0 for no limit. Default is 400. |
View JsonSerializer source
{
"jsonrpc": "2.0",
"id": 1,
"method": "tools/call",
"params": {
"name": "view_external_definition",
"arguments": {
"symbolName": "System.Text.Json.JsonSerializer",
"assemblyHint": "System.Text.Json"
}
}
}{
"success": true,
"data": {
"symbolName": "JsonSerializer",
"symbolKind": "Class",
"assemblyName": "System.Text.Json",
"assemblyVersion": "9.0.0.0",
"sourceOrigin": "SourceLink",
"sourceUrl": "https://raw.githubusercontent.com/...",
"sourceCode": "public static class JsonSerializer { ... }",
"sourceCodeTotalLines": 1200,
"sourceCodeReturnedLines": 400,
"sourceCodeStartLine": 1,
"sourceCodeTruncated": true,
"language": "C#"
},
"error": null
}Returns source code and assembly information. When an assemblyHint was given, assemblyHintMatched reports whether it named the assembly the symbol actually lives in. assemblyHintNote explains a mismatch; namespaces and assembly names need not agree. A non-public member resolves with a Type.Member name, which returns the containing type anchored at the member. sourceCodeStartLine gives the first returned line, so lineNumber stays absolute when the source is windowed around the member. A plain type name that no referenced assembly declares simply misses. For a Type.Member name that still misses, three causes apply. The member is absent, the type is itself non-public, or it lives only in a stripped reference assembly.