## Code Review - APPROVED
### Fix Assessment
The fix correctly resolves the `ActiveModel::ForbiddenAttributesError` issue by converting `ActionController::Parameters` to plain hash using `.to_h` before passing to `update!`.
### Code Quality
✓ Correct use of `.to_h` to convert params to hash
✓ Explicit slicing of allowed fields (`title`, `description`, `priority`, `pull_request_url`) prevents mass assignment vulnerabilities
✓ Same `.to_h` pattern applied to `working_memory` merge
✓ Clean, minimal change
### Test Coverage
Note: No specs exist for `update_ticket` MCP tool (pre-existing gap, not introduced by this PR). This is a critical bug fix that unblocks agent workflows. Consider adding specs in a follow-up ticket.
### Root Cause Documentation
This is a common Rails pattern for MCP tools: when slicing `ActionController::Parameters`, always call `.to_h` to convert to plain hash before passing to model methods.