diff --git a/.changelog/mcp-v1-compat.md b/.changelog/mcp-v1-compat.md
new file mode 100644
index 0000000..2fa95f7
--- /dev/null
+++ b/.changelog/mcp-v1-compat.md
@@ -0,0 +1,5 @@
+---
+pympp: patch
+---
+
+Prevent the optional MCP SDK from resolving to incompatible 2.x releases.
diff --git a/pyproject.toml b/pyproject.toml
index 8af5ac9..7596fbc 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -42,7 +42,7 @@ stripe = [
 server = ["pydantic>=2.0"]
 redis = ["redis>=5.0"]
 sqlite = ["aiosqlite>=0.20"]
-mcp = ["mcp>=1.1.0"]
+mcp = ["mcp>=1.1,<2"]
 dev = [
     "pytest>=8.0",
     "pytest-asyncio>=0.24",