Health checks were creating real resources on external platforms (e.g., Unsandbox
services/sessions) because the executor runs tools with real API keys and no
dry-run mode. This extends the tpmjs spec so tool authors can declare per-tool
side effect behavior: skip execution, provide safe test params with {{timestamp}}
templates, and define ordered cleanup steps to undo created resources.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>