v0.4.0

Major Release: v0.4.0

This release introduces a significant architectural improvement to how mcp-context-proxy handles configuration, along with comprehensive test coverage improvements.

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Breaking Change: Three-Level Configuration Architecture

What Changed

Previous versions (v0.3.x) used a flat configuration structure where all settings were in a single level. Version 0.4.0 introduces a three-level hierarchy that provides much greater flexibility:

# v0.4.0 structure
defaults:          # Built-in fallback configuration
  compression: {...}
  masking: {...}
  cache: {...}

systemConfig:      # Admin/deployment-level overrides
  compression: {...}

userConfig:        # User-specific overrides (highest priority)
  compression: {...}

Why This Matters

The three-level architecture enables:

1. Clean separation of concerns - Defaults, system requirements, and user preferences are clearly separated
2. Deployment flexibility - System admins can set organizational policies while users retain customization freedom
3. Per-server & per-tool overrides - Different compression/masking/caching rules for different MCP servers or individual tools
4. Prompt customization - System and user-level compression prompts for fine-tuned control

Example use case: An organization can enforce masking policies in systemConfig while allowing developers to customize compression thresholds in userConfig.

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Automatic Migration

Your existing v0.3.x configs will continue to work!

When v0.4.0 detects a legacy config file, it:

1. Automatically migrates the structure to v0.4.0 format
2. Preserves all your settings - nothing is lost
3. Creates a backup at <config>.backup-v0.3.x
4. Logs the migration for your review

[info] Migrated legacy v0.3.x config to v0.4.0 format
[info] Original config backed up to: mcpcp.config.yaml.backup-v0.3.x

The migration is handled by src/config/migration.ts with comprehensive test coverage to ensure reliability.

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Migration Guide

For Most Users (Automatic)

Simply upgrade and run - your config will be migrated automatically on first launch.

For Advanced Users

Review the new structure in CONFIGURATION.md and consider:

• Moving deployment-wide settings to systemConfig
• Using per-server overrides for different MCP servers
• Customizing compression prompts at system/user levels

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Full Changelog

What's Changed

• Release v0.4.0: Three-level config architecture and comprehensive test coverage by @samteezy in #14

Full Changelog: v0.3.3...v0.4.0