Reference
Runtime variable reference
Agent Plugins v1 MCP runtime variables.
Runtime variable reference
Clients that launch a portable stdio MCP server provide these values:
| Variable | Description |
|---|---|
${PLUGIN_ROOT} | Absolute, resolved root of the installed plugin package. |
${PLUGIN_DATA} | Writable persistent data directory for the installed plugin instance. |
Expansion is single-pass in MCP args, env values, and cwd. Unknown
placeholder-like text remains literal. command, url, and HTTP headers are
not expanded.