diff --git a/lib/mongo/client.rb b/lib/mongo/client.rb
index 13465ee06e..e168c95f4d 100644
--- a/lib/mongo/client.rb
+++ b/lib/mongo/client.rb
@@ -589,10 +589,11 @@ def list_mongo_databases(filter = {}, opts = {})
     # @example Start a session.
     #   client.start_session(causal_consistency: true)
     #
-    # @param [ Hash ] options The session options.
+    # @param [ Hash ] options The session options. Accepts the options
+    #   that Session#initialize accepts.
     #
-    # @note A Session cannot be used by multiple threads at once; session objects are not
-    #   thread-safe.
+    # @note A Session cannot be used by multiple threads at once; session
+    #   objects are not thread-safe.
     #
     # @return [ Session ] The session.
     #
diff --git a/lib/mongo/database.rb b/lib/mongo/database.rb
index 90ddd88df4..3809b83c68 100644
--- a/lib/mongo/database.rb
+++ b/lib/mongo/database.rb
@@ -150,6 +150,7 @@ def collections
     # @param [ Hash ] opts The command options.
     #
     # @option opts :read [ Hash ] The read preference for this command.
+    # @option opts :session [ Session ] The session to use for this command.
     #
     # @return [ Hash ] The result of the command execution.
     def command(operation, opts = {})
diff --git a/lib/mongo/session.rb b/lib/mongo/session.rb
index 87ce387c17..6d08e649d6 100644
--- a/lib/mongo/session.rb
+++ b/lib/mongo/session.rb
@@ -114,6 +114,13 @@ class Session
     # @param [ Client ] client The client through which this session is created.
     # @param [ Hash ] options The options for this session.
     #
+    # @option options [ true|false ] :causal_consistency Whether to enable
+    #   causal consistency for this session.
+    # @option options [ Hash ] :default_transaction_options Options to pass
+    #   to start_transaction by default, can contain any of the options that
+    #   start_transaction accepts.
+    # @option options [ true|false ] :implicit For internal driver use only -
+    #   specifies whether the session is implicit.
     # @option options [ Hash ] :read_preference The read preference options hash,
     #   with the following optional keys:
     #   - *:mode* -- the read preference as a string or symbol; valid values are
diff --git a/spec/support/transactions.rb b/spec/support/transactions.rb
index 9e129abbda..6b7dec77f4 100644
--- a/spec/support/transactions.rb
+++ b/spec/support/transactions.rb
@@ -257,9 +257,7 @@ def setup_test
         coll = support_client[@spec.collection_name]
         coll.database.drop
         coll.with(write: { w: :majority }).drop
-        support_client.command(
-          { create: @spec.collection_name },
-          { write_concern: { w: :majority } })
+        support_client.command(create: @spec.collection_name)
 
         coll.with(write: { w: :majority }).insert_many(@data) unless @data.empty?
         admin_support_client.command(@fail_point) if @fail_point