diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -28,6 +28,10 @@
         The tests expect:
         - `/usr/share/elasticsearch/jdk/bin/java` to exist.
         - `org.elasticsearch.bootstrap.Elasticsearch` to be in java's classpath.
+- The `tree-sitter` module is required in the python venv to launch the yarn build. To install it, run:
+```bash
+pip install tree-sitter==0.19.0
+```
 - Emscripten is required for generating tree-sitter WASM module. The following commands need to be executed for the setup:
     ```bash
     cd /opt && git clone https://github.com/emscripten-core/emsdk.git && cd emsdk && \
@@ -62,4 +66,3 @@
 * **ts-build-so**: Generates `swh_ql.wasm` file from the previously generated parser using emscripten
 
 * **ts-build**: Executes both **ts-build-so** and **ts-build-so**
-