diff --git a/config.public.json b/config.public.json
index 96ca3f4..30f7998 100644
--- a/config.public.json
+++ b/config.public.json
@@ -40,6 +40,18 @@
             "zimbatm"
         ]
     },
+    "tag_paths": {
+        "6.topic: python": [
+            "pkgs/top-level/python-packages.nix",
+            "pkgs/development/interpreters/python",
+            "pkgs/development/python-modules",
+            "doc/languages-frameworks/python.md"
+        ],
+        "6.topic: ruby": [
+            "pkgs/development/interpreters/ruby",
+            "pkgs/development/ruby-modules"
+        ]
+    },
     "checkout": {
         "root": "/var/lib/gc-of-borg/.nix-test-rs"
     },
diff --git a/ofborg/src/bin/mass-rebuilder.rs b/ofborg/src/bin/mass-rebuilder.rs
index 79732d2..8f0a5a5 100644
--- a/ofborg/src/bin/mass-rebuilder.rs
+++ b/ofborg/src/bin/mass-rebuilder.rs
@@ -39,6 +39,7 @@ fn main() {
         cfg.acl(),
         cfg.runner.identity.clone(),
         events,
+        cfg.tag_paths.clone().unwrap(),
     );
 
     channel.basic_prefetch(1).unwrap();
diff --git a/ofborg/src/config.rs b/ofborg/src/config.rs
index a77a159..5381b81 100644
--- a/ofborg/src/config.rs
+++ b/ofborg/src/config.rs
@@ -7,6 +7,7 @@ use hyper::net::HttpsConnector;
 use hyper_native_tls::NativeTlsClient;
 use hubcaps::{Credentials, Github};
 use nix::Nix;
+use std::collections::HashMap;
 
 
 use ofborg::acl;
@@ -20,6 +21,7 @@ pub struct Config {
     pub rabbitmq: RabbitMQConfig,
     pub github: Option<GithubConfig>,
     pub log_storage: Option<LogStorage>,
+    pub tag_paths: Option<HashMap<String, Vec<String>>>,
 }
 
 #[derive(Serialize, Deserialize, Debug)]
diff --git a/ofborg/src/tasks/massrebuilder.rs b/ofborg/src/tasks/massrebuilder.rs
index 53c0596..dfcfaee 100644
--- a/ofborg/src/tasks/massrebuilder.rs
+++ b/ofborg/src/tasks/massrebuilder.rs
@@ -15,7 +15,7 @@ use ofborg::nix::Nix;
 use ofborg::acl::ACL;
 use ofborg::stats;
 use ofborg::worker;
-use ofborg::tagger::{StdenvTagger, RebuildTagger};
+use ofborg::tagger::{StdenvTagger, RebuildTagger, PathsTagger};
 use ofborg::outpathdiff::{OutPaths, OutPathDiff};
 use ofborg::evalchecker::EvalChecker;
 use ofborg::commitstatus::CommitStatus;
@@ -30,6 +30,7 @@ pub struct MassRebuildWorker<E> {
     acl: ACL,
     identity: String,
     events: E,
+    tag_paths: HashMap<String, Vec<String>>,
 }
 
 impl<E: stats::SysEvents> MassRebuildWorker<E> {
@@ -40,6 +41,7 @@ impl<E: stats::SysEvents> MassRebuildWorker<E> {
         acl: ACL,
         identity: String,
         events: E,
+        tag_paths: HashMap<String, Vec<String>>,
     ) -> MassRebuildWorker<E> {
         return MassRebuildWorker {
             cloner: cloner,
@@ -48,12 +50,27 @@ impl<E: stats::SysEvents> MassRebuildWorker<E> {
             acl: acl,
             identity: identity,
             events: events,
+            tag_paths: tag_paths
         };
     }
 
     fn actions(&self) -> massrebuildjob::Actions {
         return massrebuildjob::Actions {};
     }
+
+    fn tag_from_paths(&self, issue: &hubcaps::issues::IssueRef, paths: Vec<String>) {
+        let mut tagger = PathsTagger::new(self.tag_paths.clone());
+
+        for path in paths {
+            tagger.path_changed(&path);
+        }
+
+        update_labels(
+            &issue,
+            tagger.tags_to_add(),
+            tagger.tags_to_remove(),
+        );
+    }
 }
 
 impl<E: stats::SysEvents> worker::SimpleWorker for MassRebuildWorker<E> {
@@ -199,6 +216,11 @@ impl<E: stats::SysEvents> worker::SimpleWorker for MassRebuildWorker<E> {
                 vec!["".to_owned()],
             ));
 
+        self.tag_from_paths(
+            &issue,
+            co.files_changed_from_head(&job.pr.head_sha).unwrap_or(vec![])
+        );
+
         overall_status.set_with_description("Merging PR", hubcaps::statuses::State::Pending);
 
         if let Err(_) = co.merge_commit(job.pr.head_sha.as_ref()) {