diff --git a/pkg/analysis_server/lib/src/lsp/mapping.dart b/pkg/analysis_server/lib/src/lsp/mapping.dart
index 74b40ef..e97f557 100644
--- a/pkg/analysis_server/lib/src/lsp/mapping.dart
+++ b/pkg/analysis_server/lib/src/lsp/mapping.dart
@@ -325,8 +325,6 @@
       ? suggestion.displayText
       : suggestion.completion;
 
-  final useSnippets =
-      completionCapabilities?.completionItem?.snippetSupport == true;
   final useDeprecated =
       completionCapabilities?.completionItem?.deprecatedSupport == true;
   final formats = completionCapabilities?.completionItem?.documentationFormat;
@@ -352,7 +350,8 @@
     (1000000 - suggestion.relevance).toString(),
     null, // filterText uses label if not set
     null, // insertText is deprecated, but also uses label if not set
-    useSnippets ? lsp.InsertTextFormat.Snippet : lsp.InsertTextFormat.PlainText,
+    // We don't have completions that use snippets, so we always return PlainText.
+    lsp.InsertTextFormat.PlainText,
     new lsp.TextEdit(
       // TODO(dantup): If `clientSupportsSnippets == true` then we should map
       // `selection` in to a snippet (see how Dart Code does this).
@@ -475,6 +474,10 @@
   }
 
   lsp.ParameterInformation toParameterInfo(server.ParameterInfo param) {
+    // LSP 3.14.0 supports providing label offsets (to avoid clients having
+    // to guess based on substrings). We should check the
+    // signatureHelp.signatureInformation.parameterInformation.labelOffsetSupport
+    // capability when deciding to send that.
     return new lsp.ParameterInformation(getParamLabel(param), null);
   }
 
@@ -489,7 +492,15 @@
       ),
     ],
     0, // activeSignature
-    null, // activeParameter
+    // TODO(dantup): The LSP spec says this value will default to 0 if it's
+    // not supplied or outside of the value range. However, setting -1 results
+    // in no parameters being selected in VS Code, whereas null/0 will select the first.
+    // We'd like for none to be selected (since we don't support this yet) so
+    // we send -1. I've made a request for LSP to support not selecting a parameter
+    // (because you could also be on param 5 of an invalid call to a function
+    // taking only 3 arguments) here:
+    // https://github.com/Microsoft/language-server-protocol/issues/456#issuecomment-452318297
+    -1, // activeParameter
   );
 }
 
diff --git a/pkg/analysis_server/test/lsp/completion_test.dart b/pkg/analysis_server/test/lsp/completion_test.dart
index a58127e..23f9b39 100644
--- a/pkg/analysis_server/test/lsp/completion_test.dart
+++ b/pkg/analysis_server/test/lsp/completion_test.dart
@@ -177,7 +177,7 @@
     expect(item.detail, isNot(contains('deprecated')));
   }
 
-  test_plainText_simple() async {
+  test_plainText() async {
     final content = '''
     class MyClass {
       String abcdefghij;
@@ -201,41 +201,6 @@
     expect(updated, contains('a.abcdefghij'));
   }
 
-  test_snippet_simple() async {
-    final content = '''
-    class MyClass {
-      String abcdefghij;
-    }
-
-    main() {
-      MyClass a;
-      a.abc^
-    }
-    ''';
-
-    await initialize(
-        textDocumentCapabilities: withCompletionItemSnippetSupport(
-            emptyTextDocumentClientCapabilities));
-    await openFile(mainFileUri, withoutMarkers(content));
-    final res = await getCompletion(mainFileUri, positionFromMarker(content));
-    expect(res.any((c) => c.label == 'abcdefghij'), isTrue);
-    final item = res.singleWhere((c) => c.label == 'abcdefghij');
-    // ignore: deprecated_member_use
-    expect(item.insertText, anyOf(equals('abcdefghij'), isNull));
-    expect(item.insertTextFormat, equals(InsertTextFormat.Snippet));
-    final updated = applyTextEdits(withoutMarkers(content), [item.textEdit]);
-    expect(updated, contains('a.abcdefghij'));
-    expect(item.kind, equals(CompletionItemKind.Field));
-  }
-
-  @failingTest
-  test_snippet_withSelection() async {
-    // TODO(dantup): Implement snippet functionality + test.
-    // Like above, but one that actually has a selectionOffset and results in
-    // a snippet with tabstop.
-    fail('NYI');
-  }
-
   test_unopenFile() async {
     final content = '''
     class MyClass {
diff --git a/pkg/analysis_server/test/lsp/signature_help_test.dart b/pkg/analysis_server/test/lsp/signature_help_test.dart
index ae051ff..e22eec0 100644
--- a/pkg/analysis_server/test/lsp/signature_help_test.dart
+++ b/pkg/analysis_server/test/lsp/signature_help_test.dart
@@ -288,7 +288,9 @@
     final res =
         await getSignatureHelp(mainFileUri, positionFromMarker(fileContent));
 
-    expect(res.activeParameter, isNull);
+    // TODO(dantup): Update this when there is clarification on how to handle
+    // no valid selected parameter.
+    expect(res.activeParameter, -1);
     expect(res.activeSignature, equals(0));
     expect(res.signatures, hasLength(1));
     final sig = res.signatures.first;
diff --git a/pkg/analysis_server/tool/lsp_spec/README.md b/pkg/analysis_server/tool/lsp_spec/README.md
index ea9c533..a8ad68e 100644
--- a/pkg/analysis_server/tool/lsp_spec/README.md
+++ b/pkg/analysis_server/tool/lsp_spec/README.md
@@ -19,14 +19,14 @@
 Below is a list of LSP methods and their implementation status.
 
 - Method: The LSP method name
-- Basic Impl: This method has a basic implementation but may not support all capabilities
-- Capabilities: All client capabilities (in the spec at time of writing) are supported/handled correctly
+- Basic Impl: This method has an implementation but may assume some client capabilities
+- Capabilities: Only types from the original spec or as advertised in client capabilities are returned
 - Tests: Has automated tests
 - Tested Client: Has been manually tested in at least one LSP client editor
 
 | Method | Basic Impl | Capabilities | Tests | Tested Client | Notes |
 | - | - | - | - | - | - |
-| initialize | ✅ | | ✅ | ✅ | trace and other options NYI
+| initialize | ✅ | ✅ | ✅ | ✅ | trace and other options NYI
 | initialized | ✅ | ✅ | ✅ | ✅ |
 | shutdown | ✅ | ✅ | ✅ | ✅ | supported but does nothing |
 | exit | | | | | |
@@ -47,16 +47,16 @@
 | textDocument/willSaveWaitUntil | | | | |
 | textDocument/didClose | ✅ | ✅ | ✅ | ✅ |
 | textDocument/publishDiagnostics | ✅ | ✅ | ✅ | ✅ |
-| textDocument/completion | ✅ | | ✅ | |
+| textDocument/completion | ✅ | ✅ | ✅ | ✅ |
 | completionItem/resolve | | | | | not required |
-| textDocument/hover | ✅ | | ✅ | |
-| textDocument/signatureHelp | ✅ | | ✅ | | correct trigger character handling outstanding
-| textDocument/definition | ✅ | | ✅ | |
+| textDocument/hover | ✅ | ✅ | ✅ | ✅ |
+| textDocument/signatureHelp | ✅ | ✅ | ✅ | ✅ | trigger character handling outstanding
+| textDocument/definition | ✅ | ✅ | ✅ | ✅ |
 | textDocument/typeDefinition | | | | |
 | textDocument/implementation | | | | |
-| textDocument/references | ✅ | | ✅ | |
+| textDocument/references | ✅ | ✅ | ✅ | ✅ |
 | textDocument/documentHighlight | | | | |
-| textDocument/documentSymbol | ✅ | | ✅ | |
+| textDocument/documentSymbol | ✅ | ✅ | ✅ | ✅ |
 | textDocument/codeAction (sortMembers) | ✅ | ✅ | ✅ | ✅ |
 | textDocument/codeAction (organiseImports) | ✅ | ✅ | ✅ | ✅ |
 | textDocument/codeAction (refactors) | | | | |