Add Transaction Configuration section and access-mode header

modules/ROOT/content-nav.adoc

@@ -5,6 +5,8 @@
 ** xref:actions/transaction-flow.adoc[]
 ** xref:actions/query-format.adoc[]
 ** xref:actions/result-format.adoc[]
+** xref:actions/routing.adoc[]
+** xref:actions/transaction-configuration.adoc[]
 ** xref:actions/begin-a-transaction.adoc[]
 ** xref:actions/execute-statements-in-an-open-transaction.adoc[]
 ** xref:actions/reset-transaction-timeout-of-an-open-transaction.adoc[]

modules/ROOT/pages/actions/index.adoc

@@ -11,6 +11,7 @@ There are several _actions_ that can be performed using the Cypher transaction H
 * xref:actions/query-format.adoc[]
 * xref:actions/result-format.adoc[]
 * xref:actions/routing.adoc[]
+* xref:actions/transaction-configuration.adoc[]
 
 *Using the API:*
 

modules/ROOT/pages/actions/routing.adoc

@@ -19,7 +19,9 @@ The level of support depends on whether link:https://neo4j.com/docs/operations-m
 |Clusters support routing for queries that involve a xref::/actions/begin-and-commit-a-transaction-in-one-request.adoc[single request] (i.e. via the `tx/commit` endpoint).
 This is because the cluster does not currently support transaction identifiers across the cluster.
 
-In this context, all queries are considered `WRITE` queries, even if they contain no cypher with write operations.
-Since the HTTP API did not previously support marking queries as `READ` or `WRITE`, the server assumes all queries are `WRITE` queries to support all cases.
-The effect of this is that all queries are ultimately executed on the leader.
+By default, all transactions are considered `WRITE` transactions, even if they contain no Cypher with write operations.
+This can be overridden by setting a value of `READ` in the `access-mode` header of the request (For more information, see xref::/actions/transaction-configuration.adoc[Transaction Configuration - Access Mode]).
+
+This default value ensures that all queries are ultimately run on the leader.
+To ensure efficient load balancing of `READ` transactions, you should label them as such in the request.
 |===

modules/ROOT/pages/actions/transaction-configuration.adoc

@@ -0,0 +1,18 @@
+:description: Configuring HTTP Transactions.
+
+[[http-api-actions-transaction-configuration]]
+= Transaction Configuration
+
+For any transaction-initiating request (such as `/tx` or `tx/commit`), you can provide configuration options that apply for the duration of the whole transaction.
+
+== Access Mode
+To ensure that efficient load balancing across a cluster, it is important to label transactions that only contain `READ` statements with a `READ` access mode.
+
+This can be done by adding an `access-mode` header to the request, with a value of `READ`.
+
+[WARNING]
+====
+If an `access-mode` configuration has *not* been provided, the default value is `WRITE`.
+
+However, if you have clusters with link:https://neo4j.com/docs/operations-manual/current/clustering/internals/#clustering-routing[Server-side routing] disabled, the default value is `READ`.
+====