diff --git a/src/main/java/info/textgrid/services/aggregator/REST.java b/src/main/java/info/textgrid/services/aggregator/REST.java
index 1c63f26d5c95eadb2d99c178f70034ab2c781494..0b7f9b4ff15df96e01ce0f07fd5ee5e6490b7ab1 100644
--- a/src/main/java/info/textgrid/services/aggregator/REST.java
+++ b/src/main/java/info/textgrid/services/aggregator/REST.java
@@ -121,7 +121,7 @@ public Response getEPUB(
public Response getHTML(
@Description("The TextGrid URIs of the TEI document(s) or aggregation(s) to transform, separated by commas") @PathParam("object") final String uriList,
@Description("If given, an alternative XSLT stylesheet to use. Must be a textgrid URI.") @QueryParam("stylesheet") final URI xsluri,
- @Description("If true, check for an <?xsl-stylesheet?> processing instruction in the document to render. Only textgrid: URIs will be resolved.") @QueryParam("pi") final boolean pi,
+ @Description("If true, check for an <?xsl-stylesheet?> processing instruction in the document to render. Only textgrid: URIs will be resolved.") @QueryParam("pi") @DefaultValue("true") final boolean pi,
@Description("If true and a stylesheet has been given, force reloading the stylesheet, do not cache") @QueryParam("refreshStylesheet") final boolean refreshStylesheet,
@Description("Session ID to access protected resources") @QueryParam("sid") final String sid,
@Description("If true, an HTML fragment consisting of a <div class='body'> element containing the contents of the HTML <body> will be returned, ready to be embedded in an existing HTML page") @QueryParam("embedded") final boolean embedded,