AWS Infrastructure as Code server fails on Python 3.14 due to Pydantic V1 incompatibility

[AlessandroTolomio]

Power

AWS Infrastructure as Code - Build AWS infrastructure with CDK and CloudFormation

Issue

The MCP server fails to start when using Python 3.14, preventing the power from loading any tools. The server crashes during initialization due to a Pydantic V1 compatibility issue in the samtranslator dependency.

Stack Trace

samtranslator/compat.py:2: UserWarning: Core Pydantic V1 functionality isn't compatible with Python 3.14 or greater.

RuntimeError: no validator found for <class 'pydantic.v1.fields.UndefinedType'>, see `arbitrary_types_allowed` in Config
    at samtranslator/internal/schema_source/aws_serverless_connector.py:16

Workaround

Force Python 3.12 in Kiro MCP configuration:

"args": ["--python", "3.12", "awslabs.aws-iac-mcp-server@latest"]