diff --git a/pyproject.toml b/pyproject.toml
index 2a9ad077e..d035bc851 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -55,6 +55,8 @@ required-version = ">=0.9.5"
 
 [dependency-groups]
 dev = [
+    # We add mcp[cli,ws] so `uv sync` considers the extras.
+    "mcp[cli,ws]",
     "pyright>=1.1.400",
     "pytest>=8.3.4",
     "ruff>=0.8.5",
diff --git a/uv.lock b/uv.lock
index d2a515863..39f7a6360 100644
--- a/uv.lock
+++ b/uv.lock
@@ -756,6 +756,7 @@ dev = [
     { name = "coverage", extra = ["toml"] },
     { name = "dirty-equals" },
     { name = "inline-snapshot" },
+    { name = "mcp", extra = ["cli", "ws"] },
     { name = "pillow" },
     { name = "pyright" },
     { name = "pytest" },
@@ -803,6 +804,7 @@ dev = [
     { name = "coverage", extras = ["toml"], specifier = ">=7.13.1" },
     { name = "dirty-equals", specifier = ">=0.9.0" },
     { name = "inline-snapshot", specifier = ">=0.23.0" },
+    { name = "mcp", extras = ["cli", "ws"], editable = "." },
     { name = "pillow", specifier = ">=12.0" },
     { name = "pyright", specifier = ">=1.1.400" },
     { name = "pytest", specifier = ">=8.3.4" },