Upgrade Node.js to 20+ to fix MCP server undici compatibility

[Copilot]

MCP servers fail in Lambda with ReferenceError: File is not defined because the base image ships Node.js 18 via dnf, but undici (used by mcp-remote) requires Node.js 20+ for the File API.

Changes

• Node.js installation: Replace dnf package (v18) with NodeSource repository setup to install v20+
• npm cache: Configure /tmp/.npm cache directory for Lambda's read-only filesystem constraints

# Before
RUN dnf install -y nodejs npm && \
    dnf clean all && \
    npm install -g @anthropic-ai/claude-code

# After  
RUN curl -fsSL https://rpm.nodesource.com/setup_20.x | bash - && \
    dnf install -y nodejs && \
    dnf clean all && \
    npm install -g @anthropic-ai/claude-code

RUN mkdir -p /tmp/.npm && chmod -R 777 /tmp/.npm
ENV npm_config_cache=/tmp/.npm

Affects all command-based MCP servers (e.g., AWS documentation server via uvx).

Original prompt

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This section details on the original issue you should resolve

<issue_title>MCP connection fails: Node.js 18 incompatible with undici (requires 20+)</issue_title>
<issue_description>## Problem
MCP servers fail to connect in Lambda environment with error:

ReferenceError: File is not defined
    at Object.<anonymous> (/tmp/.npm/_npx/.../node_modules/undici/lib/web/webidl/index.js:533:48)
Node.js v18.12.1

Root Cause

The Lambda base image (public.ecr.aws/lambda/python:3.12-arm64) ships with Node.js 18 via dnf install nodejs. The undici library (used by mcp-remote) requires Node.js 20+ for the File API.

Solution

Upgrade Node.js in Dockerfile from dnf package to NodeSource repository:

# Install Node.js 20+ (required for MCP's undici dependency)
RUN curl -fsSL https://rpm.nodesource.com/setup_20.x | bash - && \
    dnf install -y nodejs && \
    dnf clean all && \
    npm install -g @anthropic-ai/claude-code

# Fix npm cache permissions for Lambda
RUN mkdir -p /tmp/.npm && chmod -R 777 /tmp/.npm
ENV npm_config_cache=/tmp/.npm

Environment

• Lambda base image: public.ecr.aws/lambda/python:3.12-arm64
• Node.js version: 18.12.1 (from dnf)
• MCP server: cloudflare-radar (uses npx mcp-remote)</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes MCP connection fails: Node.js 18 incompatible with undici (requires 20+) #24

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