feat(mcp): add enable/disable commands for MCP servers (#11057) (#16299)

Co-authored-by: Allen Hutchison <adh@google.com>

docs/tools/mcp-server.md

@@ -1038,6 +1038,29 @@ gemini mcp remove my-server
 This will find and delete the "my-server" entry from the `mcpServers` object in
 the appropriate `settings.json` file based on the scope (`-s, --scope`).
 
+### Enabling/disabling a server (`gemini mcp enable`, `gemini mcp disable`)
+
+Temporarily disable an MCP server without removing its configuration, or
+re-enable a previously disabled server.
+
+**Commands:**
+
+```bash
+gemini mcp enable <name> [--session]
+gemini mcp disable <name> [--session]
+```
+
+**Options (flags):**
+
+- `--session`: Apply change only for this session (not persisted to file).
+
+Disabled servers appear in `/mcp` status as "Disabled" but won't connect or
+provide tools. Enablement state is stored in
+`~/.gemini/mcp-server-enablement.json`.
+
+The same commands are available as slash commands during an active session:
+`/mcp enable <name>` and `/mcp disable <name>`.
+
 ## Instructions
 
 Gemini CLI supports