diff --git a/libsolidity/lsp/LanguageServer.cpp b/libsolidity/lsp/LanguageServer.cpp
index 671476ab0..8a42ca104 100644
--- a/libsolidity/lsp/LanguageServer.cpp
+++ b/libsolidity/lsp/LanguageServer.cpp
@@ -76,6 +76,7 @@ LanguageServer::LanguageServer(Transport& _transport):
 		{"exit", [this](auto, auto) { m_state = (m_state == State::ShutdownRequested ? State::ExitRequested : State::ExitWithoutShutdown); }},
 		{"initialize", bind(&LanguageServer::handleInitialize, this, _1, _2)},
 		{"initialized", [](auto, auto) {}},
+		{"$/setTrace", bind(&LanguageServer::setTrace, this, _2)},
 		{"shutdown", [this](auto, auto) { m_state = State::ShutdownRequested; }},
 		{"textDocument/definition", GotoDefinition(*this) },
 		{"textDocument/didOpen", bind(&LanguageServer::handleTextDocumentDidOpen, this, _2)},
@@ -166,6 +167,13 @@ void LanguageServer::compileAndUpdateDiagnostics()
 		diagnosticsBySourceUnit[*location->sourceName].append(jsonDiag);
 	}
 
+	if (m_client.traceValue() != TraceValue::Off)
+	{
+		Json::Value extra;
+		extra["openFileCount"] = Json::UInt64(diagnosticsBySourceUnit.size());
+		m_client.trace("Number of currently open files: " + to_string(diagnosticsBySourceUnit.size()), extra);
+	}
+
 	m_nonemptyDiagnostics.clear();
 	for (auto&& [sourceUnitName, diagnostics]: diagnosticsBySourceUnit)
 	{
@@ -273,6 +281,21 @@ void LanguageServer::handleWorkspaceDidChangeConfiguration(Json::Value const& _a
 		changeConfiguration(_args["settings"]);
 }
 
+void LanguageServer::setTrace(Json::Value const& _args)
+{
+	if (!_args["value"].isString())
+		// Simply ignore invalid parameter.
+		return;
+
+	string const stringValue = _args["value"].asString();
+	if (stringValue == "off")
+		m_client.setTrace(TraceValue::Off);
+	else if (stringValue == "messages")
+		m_client.setTrace(TraceValue::Messages);
+	else if (stringValue == "verbose")
+		m_client.setTrace(TraceValue::Verbose);
+}
+
 void LanguageServer::handleTextDocumentDidOpen(Json::Value const& _args)
 {
 	requireServerInitialized();
diff --git a/libsolidity/lsp/LanguageServer.h b/libsolidity/lsp/LanguageServer.h
index d2ad09367..e827f6259 100644
--- a/libsolidity/lsp/LanguageServer.h
+++ b/libsolidity/lsp/LanguageServer.h
@@ -68,6 +68,7 @@ private:
 	void requireServerInitialized();
 	void handleInitialize(MessageID _id, Json::Value const& _args);
 	void handleWorkspaceDidChangeConfiguration(Json::Value const& _args);
+	void setTrace(Json::Value const& _args);
 	void handleTextDocumentDidOpen(Json::Value const& _args);
 	void handleTextDocumentDidChange(Json::Value const& _args);
 	void handleTextDocumentDidClose(Json::Value const& _args);
diff --git a/libsolidity/lsp/Transport.cpp b/libsolidity/lsp/Transport.cpp
index fcd3c8249..b82b34ec4 100644
--- a/libsolidity/lsp/Transport.cpp
+++ b/libsolidity/lsp/Transport.cpp
@@ -98,6 +98,18 @@ void IOStreamTransport::error(MessageID _id, ErrorCode _code, string _message)
 	send(move(json), _id);
 }
 
+void Transport::trace(std::string _message, Json::Value _extra)
+{
+	if (m_logTrace != TraceValue::Off)
+	{
+		Json::Value params;
+		if (_extra.isObject())
+			params = move(_extra);
+		params["message"] = move(_message);
+		notify("$/logTrace", move(params));
+	}
+}
+
 void IOStreamTransport::send(Json::Value _json, MessageID _id)
 {
 	solAssert(_json.isObject());
diff --git a/libsolidity/lsp/Transport.h b/libsolidity/lsp/Transport.h
index 82fe43909..d84edf49d 100644
--- a/libsolidity/lsp/Transport.h
+++ b/libsolidity/lsp/Transport.h
@@ -34,6 +34,13 @@ namespace solidity::lsp
 
 using MessageID = Json::Value;
 
+enum class TraceValue
+{
+	Off,
+	Messages,
+	Verbose
+};
+
 enum class ErrorCode
 {
 	// Defined by JSON RPC
@@ -89,6 +96,15 @@ public:
 	virtual void notify(std::string _method, Json::Value _params) = 0;
 	virtual void reply(MessageID _id, Json::Value _result) = 0;
 	virtual void error(MessageID _id, ErrorCode _code, std::string _message) = 0;
+
+	void trace(std::string _message, Json::Value _extra = Json::nullValue);
+
+	TraceValue traceValue() const noexcept { return m_logTrace; }
+	void setTrace(TraceValue _value) noexcept { m_logTrace = _value; }
+
+
+private:
+	TraceValue m_logTrace = TraceValue::Off;
 };
 
 /**