diff --git a/.github/workflows/check-tests.yml b/.github/workflows/check-tests.yml
index 8570c30..b0d4e76 100644
--- a/.github/workflows/check-tests.yml
+++ b/.github/workflows/check-tests.yml
@@ -24,7 +24,7 @@ jobs:
         uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
 
       - name: Install dependencies
-        run: python -m pip install -U "copier>=8.0.0" jinja2-time "jupyterlab>=4.0.0,<5" "pydantic<2.0.0"
+        run: python -m pip install -U "copier>=8.0.0" jinja2-time "jupyterlab>=4.0.0,<5" "pydantic<2.0.0" "pyyaml-include<2.0"
 
       - name: Create the extension
         run: |
@@ -93,7 +93,7 @@ jobs:
         uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
 
       - name: Install dependencies
-        run: python -m pip install -U "copier>=8.0.0" jinja2-time "jupyterlab>=4.0.0,<5" "pydantic<2.0.0"
+        run: python -m pip install -U "copier>=8.0.0" jinja2-time "jupyterlab>=4.0.0,<5" "pydantic<2.0.0" "pyyaml-include<2.0"
 
       - name: Create the extension
         run: |
@@ -115,7 +115,7 @@ jobs:
         working-directory: myextension/ui-tests
         env:
           PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD: 1
-          YARN_ENABLE_IMMUTABLE_INSTALLS: false 
+          YARN_ENABLE_IMMUTABLE_INSTALLS: false
         run: jlpm install
 
       - name: Set up browser cache
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index f79983b..9be94c5 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -40,7 +40,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          python -m pip install "copier>=8.0.0" jinja2-time "pydantic<2.0.0"
+          python -m pip install "copier>=8.0.0" jinja2-time "pydantic<2.0.0" "pyyaml-include<2.0"
 
       - name: Create pure frontend extension
         env:
@@ -82,7 +82,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          python -m pip install "copier>=8.0.0" jinja2-time "pydantic<2.0.0"
+          python -m pip install "copier>=8.0.0" jinja2-time "pydantic<2.0.0" "pyyaml-include<2.0"
 
       - name: Setup Git
         run: |
@@ -126,7 +126,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          python -m pip install "copier>=8.0.0" jinja2-time "pydantic<2.0.0"
+          python -m pip install "copier>=8.0.0" jinja2-time "pydantic<2.0.0" "pyyaml-include<2.0"
 
       - name: Setup Git
         run: |
@@ -170,7 +170,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          python -m pip install "copier>=8.0.0" jinja2-time "pydantic<2.0.0"
+          python -m pip install "copier>=8.0.0" jinja2-time "pydantic<2.0.0" "pyyaml-include<2.0"
 
       - name: Setup Git
         run: |
@@ -218,7 +218,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          python -m pip install "copier>=8.0.0" jinja2-time build "pydantic<2.0.0"
+          python -m pip install "copier>=8.0.0" jinja2-time build "pydantic<2.0.0" "pyyaml-include<2.0"
 
       - name: Setup Git
         run: |
@@ -388,7 +388,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          python -m pip install "copier>=8.0.0" jinja2-time build "pydantic<2.0.0"
+          python -m pip install "copier>=8.0.0" jinja2-time build "pydantic<2.0.0" "pyyaml-include<2.0"
 
       - name: Setup Git
         run: |
@@ -432,7 +432,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          python -m pip install "copier>=8.0.0" jinja2-time build "pydantic<2.0.0"
+          python -m pip install "copier>=8.0.0" jinja2-time build "pydantic<2.0.0" "pyyaml-include<2.0"
 
       - name: Setup Git
         run: |
@@ -475,7 +475,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          python -m pip install "copier>=8.0.0" jinja2-time "pydantic<2.0.0"
+          python -m pip install "copier>=8.0.0" jinja2-time "pydantic<2.0.0" "pyyaml-include<2.0"
 
       - name: Setup Git
         run: |
diff --git a/README.md b/README.md
index 7ab49cf..1ae1c2a 100644
--- a/README.md
+++ b/README.md
@@ -16,13 +16,13 @@ a JupyterLab extension. Four kinds of extension are supported:
 With `pip`:
 
 ```sh
-pip install "copier~=7.2" jinja2-time "pydantic<2.0.0"
+pip install "copier~=7.2" jinja2-time "pydantic<2.0.0" "pyyaml-include<2.0"
 ```
 
 Or with `conda` / `mamba`:
 
 ```sh
-conda install -c conda-forge "copier>=7,<8" jinja2-time
+conda install -c conda-forge "copier>=7,<8" jinja2-time "pyyaml-include<2.0"
 ```
 
 2. Create an extension directory and go to it.