diff --git a/.gitignore b/.gitignore
index c954a89a2..9d753dbad 100644
--- a/.gitignore
+++ b/.gitignore
@@ -166,8 +166,6 @@ cython_debug/
 # model output directories
 outputs/
 examples/basic_usage/*.xyz
-!docs/static/*.pt
-!examples/ase/*.pt
 
 # sphinx gallery
 docs/src/examples
diff --git a/.readthedocs.yml b/.readthedocs.yml
index b2a09549b..79e8befef 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -11,6 +11,9 @@ build:
   tools:
     python: "3.12"
     rust: "1.75"
+  jobs:
+    pre_build:
+      - set -e && cd examples/ase && bash train.sh
 
 
 # Build documentation in the docs/ directory with Sphinx
@@ -28,5 +31,6 @@ python:
   - method: pip
     path: .
     extra_requirements:
+      - gap
       - soap-bpnn
   - requirements: docs/requirements.txt
diff --git a/docs/static/qm9/options.yaml b/docs/static/qm9/options.yaml
index 9604fdcf3..d6516bfba 100644
--- a/docs/static/qm9/options.yaml
+++ b/docs/static/qm9/options.yaml
@@ -1,6 +1,8 @@
 # architecture used to train the model
 architecture:
   name: experimental.soap_bpnn
+  training:
+    num_epochs: 5  # a very short training run
 
 # Mandatory section defining the parameters for system and target data of the
 # training set
diff --git a/examples/ase/model.pt b/examples/ase/model.pt
deleted file mode 100644
index 866967d0f..000000000
Binary files a/examples/ase/model.pt and /dev/null differ
diff --git a/examples/ase/options.yaml b/examples/ase/options.yaml
index 6f2ff95da..4a54f2c66 100644
--- a/examples/ase/options.yaml
+++ b/examples/ase/options.yaml
@@ -1,13 +1,7 @@
-device: cpu
-
 architecture:
-  name: experimental.soap_bpnn
-  training:
-    batch_size: 16
-    num_epochs: 100
-    learning_rate: 0.01
+  name: experimental.gap
 
-# Section defining the parameters for system and target data
+# training set section
 training_set:
   systems: "ethanol_reduced_100.xyz"
   targets:
diff --git a/examples/ase/train.sh b/examples/ase/train.sh
index 1047004d4..f73b048e6 100755
--- a/examples/ase/train.sh
+++ b/examples/ase/train.sh
@@ -1,4 +1,3 @@
 #!/bin/bash
 
-metatrain train options.yaml
-
+mtt train options.yaml
diff --git a/examples/basic_usage/usage.sh b/examples/basic_usage/usage.sh
index 70fda6fc8..b4986838d 100755
--- a/examples/basic_usage/usage.sh
+++ b/examples/basic_usage/usage.sh
@@ -3,14 +3,17 @@
 mtt train options.yaml
 
 # The functions saves the final model `model.pt` to the current output folder for later
-# evaluation. All command line flags of the train sub-command can be listed via
+# evaluation. An `extensions/` folder, which contains the compiled extensions for the model,
+# might also be saved depending on the architecture.
+# All command line flags of the train sub-command can be listed via
 
 mtt train --help
 
 # We now evaluate the model on the training dataset, where the first arguments specifies
 # trained model and the second an option file containing the path of the dataset for evaulation.
+# The extensions of the model, if any, can be specified via the `-e` flag.
 
-mtt eval model.pt eval.yaml
+mtt eval model.pt eval.yaml -e extensions/
 
 # The evaluation command predicts those properties the model was trained against; here
 # "U0". The predictions together with the systems have been written in a file named
diff --git a/src/metatrain/experimental/gap/model.py b/src/metatrain/experimental/gap/model.py
index e74ed1c7b..06b314749 100644
--- a/src/metatrain/experimental/gap/model.py
+++ b/src/metatrain/experimental/gap/model.py
@@ -209,7 +209,7 @@ def load_checkpoint(cls, path: Union[str, Path]) -> "GAP":
     def export(self) -> MetatensorAtomisticModel:
         capabilities = ModelCapabilities(
             outputs=self.outputs,
-            atomic_types=self.dataset_info.atomic_types,
+            atomic_types=sorted(self.dataset_info.atomic_types),
             interaction_range=self.hypers["soap"]["cutoff"],
             length_unit=self.dataset_info.length_unit,
             supported_devices=["cuda", "cpu"],
diff --git a/tox.ini b/tox.ini
index f09997d75..6469c1a3c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -136,12 +136,13 @@ deps =
     -r docs/requirements.txt
 allowlist_externals =
     bash
-extras = soap-bpnn  # this model is used in the documentation
+extras = # these models are used in the documentation
+    gap
+    soap-bpnn
 commands =
-    # Run .sh scripts in the example folder.
-    #bash -c "set -e && cd {toxinidir}/examples/basic_usage && bash usage.sh"
-    # Disable slow training at runtime for ase example to speed up CI for now.
-    #bash -c "set -e && cd {toxinidir}/examples/ase && bash train_export.sh"
+    # Run example and usage scripts.
+    bash -c "set -e && cd {toxinidir}/examples/basic_usage && bash usage.sh"
+    bash -c "set -e && cd {toxinidir}/examples/ase && bash train.sh"
     sphinx-build \
         {posargs:-E} \
         --builder html \