diff --git a/pyproject.toml b/pyproject.toml
index 03d898e..f0b3925 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -14,6 +14,7 @@
 
 [tool.poetry.dependencies]
 python = "^3.8"
+cot-dt2c = {path = "tools/cot_dt2c", develop = true}
 tlc = {path = "tools/tlc"}
 
 [tool.poetry.group.docs]