joint.motion_link offset is read in the linked value's units (degrees or mm, or an expression); links are still stored in radians, so saved designs open unchanged. A new joint whose values fall outside its limits starts at the nearer limit, stores it, and says so in warnings. Loop dof also counts at a nearby pose, so a part at a dead point of its loop keeps its mobility. The mechanisms skill is updated to match.
The Joint and As-built Joint dialogs explain why picks make no joint and offer Create Components from Bodies when every pick is on one component; joint.create and joint.as_built suggest component.from_bodies. Labels in all catalogs. Fixes#1239.
A solidcraft-mechanisms agent skill with a worked example that a test replays through the MCP server (the actuator follows the hinge with the stated stroke and the drive stops at the rod's limit); the skills index and docs/mcp.md list it.