diff --git a/docs/index.html b/docs/index.html
index e2fb8f4..3ccf95d 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -685,7 +685,7 @@ <h3 class='fl m0' id='run'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/index.js#L272-L309'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/index.js#L272-L309'>
       <span>src/index.js</span>
       </a>
     
@@ -919,7 +919,7 @@ <h3 class='fl m0' id='simulate'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/index.js#L92-L143'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/index.js#L92-L143'>
       <span>src/index.js</span>
       </a>
     
@@ -1141,7 +1141,7 @@ <h3 class='fl m0' id='evaluate'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/index.js#L194-L231'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/index.js#L194-L231'>
       <span>src/index.js</span>
       </a>
     
@@ -1322,7 +1322,7 @@ <h3 class='fl m0' id='evaluator'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/evaluator.js#L44-L72'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/evaluator.js#L44-L72'>
       <span>src/evaluator.js</span>
       </a>
     
@@ -1400,7 +1400,7 @@ <h3 class='fl m0' id='evaluator'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/evaluator.js#L68-L70'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/evaluator.js#L68-L70'>
       <span>src/evaluator.js</span>
       </a>
     
@@ -1519,7 +1519,7 @@ <h3 class='fl m0' id='promptedevaluator'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/evaluators/prompted-evaluator.js#L27-L52'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/evaluators/prompted-evaluator.js#L27-L52'>
       <span>src/evaluators/prompted-evaluator.js</span>
       </a>
     
@@ -1652,7 +1652,7 @@ <h3 class='fl m0' id='readabilityevaluator'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/evaluators/readability-evaluator.js#L336-L355'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/evaluators/readability-evaluator.js#L336-L355'>
       <span>src/evaluators/readability-evaluator.js</span>
       </a>
     
@@ -1768,7 +1768,7 @@ <h3 class='fl m0' id='system'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/system.js#L44-L65'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/system.js#L44-L65'>
       <span>src/system.js</span>
       </a>
     
@@ -1844,7 +1844,7 @@ <h3 class='fl m0' id='system'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/system.js#L63-L63'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/system.js#L63-L63'>
       <span>src/system.js</span>
       </a>
     
@@ -1951,7 +1951,7 @@ <h3 class='fl m0' id='generativeelasticsystem'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/systems/generative-elastic-system.js#L88-L140'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/systems/generative-elastic-system.js#L89-L141'>
       <span>src/systems/generative-elastic-system.js</span>
       </a>
     
@@ -2094,10 +2094,12 @@ <h3 class='fl m0' id='generativeelasticsystem'>
 
   
     <tr>
-  <td class='break-word'><span class='code bold'>configuration.search._source_excludes</span> <code class='quiet'><a href="https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array">Array</a>?</code>
+  <td class='break-word'><span class='code bold'>configuration.search._source</span> <code class='quiet'><a href="https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object">Object</a>?</code>
   </td>
-  <td class='break-word'><span>A comma-separated
-list of source fields to exclude from the response
+  <td class='break-word'><span>An object that specifies
+which source attributes to include in the response, see
+
+<a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/search-fields.html#source-filtering">the Elasticsearch documentation</a>
 </span></td>
 </tr>
 
@@ -2212,7 +2214,7 @@ <h3 class='fl m0' id='generativeelasticsystem'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/systems/generative-elastic-system.js#L106-L138'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/systems/generative-elastic-system.js#L107-L139'>
       <span>src/systems/generative-elastic-system.js</span>
       </a>
     
@@ -2330,7 +2332,7 @@ <h3 class='fl m0' id='user'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/user.js#L47-L81'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/user.js#L47-L81'>
       <span>src/user.js</span>
       </a>
     
@@ -2408,7 +2410,7 @@ <h3 class='fl m0' id='user'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/user.js#L66-L66'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/user.js#L66-L66'>
       <span>src/user.js</span>
       </a>
     
@@ -2517,7 +2519,7 @@ <h3 class='fl m0' id='user'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/user.js#L79-L79'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/user.js#L79-L79'>
       <span>src/user.js</span>
       </a>
     
@@ -2632,7 +2634,7 @@ <h3 class='fl m0' id='staticuser'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/users/static-user.js#L25-L52'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/users/static-user.js#L25-L52'>
       <span>src/users/static-user.js</span>
       </a>
     
@@ -2779,7 +2781,7 @@ <h3 class='fl m0' id='templates'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/templates.js#L25-L82'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/templates.js#L25-L82'>
       <span>src/templates.js</span>
       </a>
     
@@ -2829,7 +2831,7 @@ <h3 class='fl m0' id='templates'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/templates.js#L25-L82'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/templates.js#L25-L82'>
       <span>src/templates.js</span>
       </a>
     
@@ -2953,7 +2955,7 @@ <h3 class='fl m0' id='templates'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/templates.js#L90-L94'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/templates.js#L90-L94'>
       <span>src/templates.js</span>
       </a>
     
@@ -3033,7 +3035,7 @@ <h3 class='fl m0' id='templates'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/templates.js#L104-L111'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/templates.js#L104-L111'>
       <span>src/templates.js</span>
       </a>
     
@@ -3124,7 +3126,7 @@ <h3 class='fl m0' id='templates'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/templates.js#L123-L138'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/templates.js#L123-L138'>
       <span>src/templates.js</span>
       </a>
     
@@ -3231,7 +3233,7 @@ <h3 class='fl m0' id='evaluation'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/index.js#L45-L61'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/index.js#L45-L61'>
       <span>src/index.js</span>
       </a>
     
@@ -3346,7 +3348,7 @@ <h3 class='fl m0' id='evaluationresult'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/evaluator.js#L3-L10'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/evaluator.js#L3-L10'>
       <span>src/evaluator.js</span>
       </a>
     
@@ -3426,7 +3428,7 @@ <h3 class='fl m0' id='evaluation_result'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/evaluator.js#L15-L24'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/evaluator.js#L15-L24'>
       <span>src/evaluator.js</span>
       </a>
     
@@ -3476,7 +3478,7 @@ <h3 class='fl m0' id='evaluation_result'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/evaluator.js#L19-L19'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/evaluator.js#L19-L19'>
       <span>src/evaluator.js</span>
       </a>
     
@@ -3534,7 +3536,7 @@ <h3 class='fl m0' id='evaluation_result'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/evaluator.js#L23-L23'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/evaluator.js#L23-L23'>
       <span>src/evaluator.js</span>
       </a>
     
@@ -3602,7 +3604,7 @@ <h3 class='fl m0' id='llm'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/llm.js#L176-L262'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/llm.js#L176-L262'>
       <span>src/llm.js</span>
       </a>
     
@@ -3677,7 +3679,7 @@ <h3 class='fl m0' id='llm'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/llm.js#L188-L190'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/llm.js#L188-L190'>
       <span>src/llm.js</span>
       </a>
     
@@ -3757,7 +3759,7 @@ <h3 class='fl m0' id='llm'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/llm.js#L197-L199'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/llm.js#L197-L199'>
       <span>src/llm.js</span>
       </a>
     
@@ -3837,7 +3839,7 @@ <h3 class='fl m0' id='llm'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/llm.js#L206-L208'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/llm.js#L206-L208'>
       <span>src/llm.js</span>
       </a>
     
@@ -3917,7 +3919,7 @@ <h3 class='fl m0' id='llm'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/llm.js#L219-L221'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/llm.js#L219-L221'>
       <span>src/llm.js</span>
       </a>
     
@@ -4015,7 +4017,7 @@ <h3 class='fl m0' id='llm'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/llm.js#L237-L260'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/llm.js#L237-L260'>
       <span>src/llm.js</span>
       </a>
     
@@ -4144,7 +4146,7 @@ <h3 class='fl m0' id='llmconfiguration'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/llm.js#L154-L166'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/llm.js#L154-L166'>
       <span>src/llm.js</span>
       </a>
     
@@ -4227,7 +4229,7 @@ <h3 class='fl m0' id='logbook'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/logbook.js#L89-L113'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/logbook.js#L89-L113'>
       <span>src/logbook.js</span>
       </a>
     
@@ -4315,7 +4317,7 @@ <h3 class='fl m0' id='logbook'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/logbook.js#L104-L111'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/logbook.js#L104-L111'>
       <span>src/logbook.js</span>
       </a>
     
@@ -4413,7 +4415,7 @@ <h3 class='fl m0' id='logbookentry'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/logbook.js#L10-L78'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/logbook.js#L10-L78'>
       <span>src/logbook.js</span>
       </a>
     
@@ -4498,7 +4500,7 @@ <h3 class='fl m0' id='logbookentry'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/logbook.js#L17-L17'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/logbook.js#L17-L17'>
       <span>src/logbook.js</span>
       </a>
     
@@ -4561,7 +4563,7 @@ <h3 class='fl m0' id='logbookentry'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/logbook.js#L22-L22'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/logbook.js#L22-L22'>
       <span>src/logbook.js</span>
       </a>
     
@@ -4624,7 +4626,7 @@ <h3 class='fl m0' id='logbookentry'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/logbook.js#L27-L27'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/logbook.js#L27-L27'>
       <span>src/logbook.js</span>
       </a>
     
@@ -4687,7 +4689,7 @@ <h3 class='fl m0' id='logbookentry'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/logbook.js#L32-L32'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/logbook.js#L32-L32'>
       <span>src/logbook.js</span>
       </a>
     
@@ -4759,7 +4761,7 @@ <h3 class='fl m0' id='logbookentry'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/logbook.js#L41-L44'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/logbook.js#L41-L44'>
       <span>src/logbook.js</span>
       </a>
     
@@ -4840,7 +4842,7 @@ <h3 class='fl m0' id='logbookentry'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/logbook.js#L50-L52'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/logbook.js#L50-L52'>
       <span>src/logbook.js</span>
       </a>
     
@@ -4906,7 +4908,7 @@ <h3 class='fl m0' id='logbookentry'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/logbook.js#L58-L60'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/logbook.js#L58-L60'>
       <span>src/logbook.js</span>
       </a>
     
@@ -4972,7 +4974,7 @@ <h3 class='fl m0' id='logbookentry'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/logbook.js#L66-L76'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/logbook.js#L66-L76'>
       <span>src/logbook.js</span>
       </a>
     
@@ -5046,7 +5048,7 @@ <h3 class='fl m0' id='simulation'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/index.js#L35-L43'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/index.js#L35-L43'>
       <span>src/index.js</span>
       </a>
     
@@ -5135,7 +5137,7 @@ <h3 class='fl m0' id='systemresponse'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/system.js#L3-L8'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/system.js#L3-L8'>
       <span>src/system.js</span>
       </a>
     
@@ -5207,7 +5209,7 @@ <h3 class='fl m0' id='system_response'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/system.js#L13-L26'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/system.js#L13-L26'>
       <span>src/system.js</span>
       </a>
     
@@ -5257,7 +5259,7 @@ <h3 class='fl m0' id='system_response'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/system.js#L17-L17'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/system.js#L17-L17'>
       <span>src/system.js</span>
       </a>
     
@@ -5315,7 +5317,7 @@ <h3 class='fl m0' id='system_response'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/system.js#L21-L21'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/system.js#L21-L21'>
       <span>src/system.js</span>
       </a>
     
@@ -5373,7 +5375,7 @@ <h3 class='fl m0' id='system_response'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/system.js#L25-L25'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/system.js#L25-L25'>
       <span>src/system.js</span>
       </a>
     
@@ -5441,7 +5443,7 @@ <h3 class='fl m0' id='topic'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/index.js#L28-L33'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/index.js#L28-L33'>
       <span>src/index.js</span>
       </a>
     
@@ -5513,7 +5515,7 @@ <h3 class='fl m0' id='userturn'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/user.js#L3-L13'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/user.js#L3-L13'>
       <span>src/user.js</span>
       </a>
     
@@ -5602,7 +5604,7 @@ <h3 class='fl m0' id='user_turn'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/user.js#L18-L27'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/user.js#L18-L27'>
       <span>src/user.js</span>
       </a>
     
@@ -5652,7 +5654,7 @@ <h3 class='fl m0' id='user_turn'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/user.js#L22-L22'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/user.js#L22-L22'>
       <span>src/user.js</span>
       </a>
     
@@ -5710,7 +5712,7 @@ <h3 class='fl m0' id='user_turn'>
   <div class='clearfix'>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/user.js#L26-L26'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/user.js#L26-L26'>
       <span>src/user.js</span>
       </a>
     
@@ -5778,7 +5780,7 @@ <h3 class='fl m0' id='touche25raduser'>
     </h3>
     
     
-      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/a94aebc559a3f2d8743ec104c9d0052e6d40feec/src/users/touche25-rad-user.js#L13-L61'>
+      <a class='fr fill-darken0 round round pad1x quiet h5' href='https://github.com/webis-de/GenIRSim/blob/794fbc8a6ab0b574b8add5b53bb345e504dd0a4c/src/users/touche25-rad-user.js#L13-L61'>
       <span>src/users/touche25-rad-user.js</span>
       </a>
     
diff --git a/src/systems/generative-elastic-system.js b/src/systems/generative-elastic-system.js
index f272540..3c617a2 100644
--- a/src/systems/generative-elastic-system.js
+++ b/src/systems/generative-elastic-system.js
@@ -69,8 +69,9 @@ async function queryElastic(query, searchConfiguration, logbook) {
  * Variables are the same as for `configuration.preprocessing.message`, plus:
  * - `{{variables.preprocessing}}`: The parsed output of the preprocessing (if
  *   preprocessing was performed)
- * @param {Array} [configuration.search._source_excludes] - A comma-separated
- * list of source fields to exclude from the response
+ * @param {Object} [configuration.search._source] - An object that specifies
+ * which source attributes to include in the response, see
+ * {@link https://www.elastic.co/guide/en/elasticsearch/reference/current/search-fields.html#source-filtering|the Elasticsearch documentation}
  * @param {number} configuration.search.size - The number of results to retrieve
  * @param {Object} configuration.generation
  * @param {string} configuration.generation.message - Template for the