registry

Introduces an environment variable MCP_REGISTRY_CUSTOM_MCP_REGISTRY_URL to allow the registry UI to load from a custom source instead of the hardcoded default. Motivation and Context Currently, the MCP Registry UI is hardcoded to https://registry.modelcontextprotocol.io/. This poses a challenge for: 1. Air-gapped environments where the official URL is unreachable. 2. Enterprise deployments that require hosting a private/mirrored registry. 3. Local development where developers need to test UI changes against a local registry instance. How Has This Been Tested? Local docker run with the ENV var Local docker run without the ENV var, loads the https://registry.modelcontextprotocol.io/ by default Breaking Changes None. Types of changes [ ] Bug fix (non-breaking change which fixes an issue) [X] New feature (non-breaking change which adds functionality) [ ] Breaking change (fix or feature that would cause existing functionality to change) [ ] Documentation update Checklist [X] I have read the MCP Documentation [X] My code follows the repository's style guidelines [X] New and existing tests pass locally [X] I have added appropriate error handling [X] I have added or updated documentation as needed Additional context https://github.com/modelcontextprotocol/registry/issues/948

Problem: Currently, the MCP Registry UI is hardcoded to load from https://registry.modelcontextprotocol.io/. In enterprise environments, air-gapped setups, or private local deployments, users may need to host their own registry or a mirrored version of the UI. There is currently no straightforward way to redirect the UI to a custom source without modifying the source code. Request: Allow MCP_REGISTRY_CUSTOM_MCP_REGISTRY_URL as a docker env parameter