Groundwork for hiding named MCP tools from Claude while apps still list them

MCP tools are extra tools that come from MCP servers, which are outside programs Claude Code connects to. Before a tool is shown to Claude, Claude Code checks whether it should be kept from the model. That check now looks at a list of tool names kept for each server. If a tool is on the list, Claude cannot see or use it, and a debug message says it was hidden because keepMcpToolsFromModel listed it. An app that embeds Claude Code still sees the tool in its MCP status report.

In this build nothing adds names to that list, so the list is always empty and no tool is hidden this way. The older check still applies: a tool whose own metadata does not include the model among its audiences stays hidden.