Plugin data folder now reaches agents, commands and skills, and can be missing

What

A plugin is an add-on package for Claude Code, and each plugin can have its own data folder, referred to as ${CLAUDE_PLUGIN_DATA}. How that is filled in changed:

• Plugin agents, commands and skills now receive the data folder (pluginDataDir, passed as dataDir), so their prompts can refer to it.
• If the folder cannot be found, filling in ${CLAUDE_PLUGIN_DATA} now fails with PluginDataDirUnknownError, which says the plugin is on another machine and its data folder there did not come with it. Before, a path was always worked out.
• A plugin command's allowed-tools (tools it may use without asking you) are now dropped when they name the plugin's data folder and that folder did not come with the plugin. The warning says so, replacing the earlier wording about entries being too long or naming a folder that holds a variable or a $.
• The plugin sync output gained a dataDirs option.

Why

Plugin authors can use the data folder in agent, command and skill prompts. Where a plugin runs on another machine, hooks or commands that rely on it may now fail with a clear error, and a command may lose its pre-approved tools.