Tool schema for create_container fails VS Code validation: array type must have items

[AlisaYuki]

Summary

Using mcp-server-docker via MCP in VS Code fails when validating tool mcp_docker_create_container with error:

Error: tool parameters array type must have items

Environment

• OS: Windows
• MCP client: VS Code (GitHub Copilot MCP integration)
• Server launch: uvx mcp-server-docker
• Package version: mcp-server-docker==0.2.1 (PyPI)

Reproduction

1. Configure MCP server:

"docker": {
  "command": "uvx",
  "args": ["mcp-server-docker"]
}

2. Start VS Code MCP and validate tools.
3. Validation fails for tool mcp_docker_create_container with message above.

Root cause

CreateContainerInput.model_json_schema() emits a tuple branch under ports:

{
  "type": "array",
  "prefixItems": [{"type":"string"},{"type":"integer"}],
  "minItems": 2,
  "maxItems": 2
}

This branch has no items, and some clients require items for all type: array schemas.

Field definition appears to be:

ports: dict[str, int | list[int] | tuple[str, int] | None] | None

Suggested fix

Use a client-compatible schema for that union branch, e.g. avoid tuple in tool input schema or provide explicit JSON schema override with items included for array branches.

Potential options:

• Replace tuple[str, int] with an object form like { "host": string, "port": int } for MCP input schema.
• Or define json_schema_extra for the field to ensure all array branches include items.

Thanks!