diff --git a/gopls/internal/lsp/protocol/generate/output.go b/gopls/internal/lsp/protocol/generate/output.go
index df7cc9c8257..e61bd0d9c1d 100644
--- a/gopls/internal/lsp/protocol/generate/output.go
+++ b/gopls/internal/lsp/protocol/generate/output.go
@@ -239,8 +239,30 @@ func genStructs(model Model) {
 		types[nm] = out.String()
 	}
 	// base types
-	types["DocumentURI"] = "type DocumentURI string\n"
-	types["URI"] = "type URI = string\n"
+	types["DocumentURI"] = `
+// A DocumentURI is the URI of a client editor document.
+//
+// Care should be taken to handle encoding in URIs. For
+// example, some clients (such as VS Code) may encode colons
+// in drive letters while others do not. The URIs below are
+// both valid, but clients and servers should be consistent
+// with the form they use themselves to ensure the other party
+// doesn’t interpret them as distinct URIs. Clients and
+// servers should not assume that each other are encoding the
+// same way (for example a client encoding colons in drive
+// letters cannot assume server responses will have encoded
+// colons). The same applies to casing of drive letters - one
+// party should not assume the other party will return paths
+// with drive letters cased the same as it.
+//
+//    file:///c:/project/readme.md
+//    file:///C%3A/project/readme.md
+//
+type DocumentURI string
+`
+	types["URI"] = `// A URI is an arbitrary URL (e.g. https), not necessarily a file.
+type URI = string
+`
 
 	types["LSPAny"] = "type LSPAny = interface{}\n"
 	// A special case, the only previously existing Or type
diff --git a/gopls/internal/lsp/protocol/tsprotocol.go b/gopls/internal/lsp/protocol/tsprotocol.go
index f571be379a8..57e54c62e02 100644
--- a/gopls/internal/lsp/protocol/tsprotocol.go
+++ b/gopls/internal/lsp/protocol/tsprotocol.go
@@ -1458,6 +1458,24 @@ type DocumentSymbolRegistrationOptions struct {
 	TextDocumentRegistrationOptions
 	DocumentSymbolOptions
 }
+
+// A DocumentURI is the URI of a client editor document.
+//
+// Care should be taken to handle encoding in URIs. For
+// example, some clients (such as VS Code) may encode colons
+// in drive letters while others do not. The URIs below are
+// both valid, but clients and servers should be consistent
+// with the form they use themselves to ensure the other party
+// doesn’t interpret them as distinct URIs. Clients and
+// servers should not assume that each other are encoding the
+// same way (for example a client encoding colons in drive
+// letters cannot assume server responses will have encoded
+// colons). The same applies to casing of drive letters - one
+// party should not assume the other party will return paths
+// with drive letters cased the same as it.
+//
+//	file:///c:/project/readme.md
+//	file:///C%3A/project/readme.md
 type DocumentURI string
 
 // Predefined error codes.
@@ -4660,6 +4678,8 @@ type UIntCommaUInt struct {
 	Fld0 uint32 `json:"fld0"`
 	Fld1 uint32 `json:"fld1"`
 }
+
+// A URI is an arbitrary URL (e.g. https), not necessarily a file.
 type URI = string
 
 // A diagnostic report indicating that the last returned