Tune the system you can see.
ParamRig is a local workbench for visual systems built in code. Something, usually an agent, declares a rig: the values that decide how a thing looks, and the instrument each one deserves. You move them against a live result and keep the state you approved.
There are three ways to use it.
Connect a project you are running
Install @paramrig/web in the project being tuned, describe its controls in .paramrig/manifest.json, and open it in the workbench. Your design tokens become controls, and your components become elements you can select, comment on and draw over.
Approving writes one immutable file into your repository. Your agent reads it, applies the values to your source, and writes a response naming the revision it produced. The web SDK is the reference. How the loop closes is the same round trip told with pictures.
Draw it in one of the editors
ParamRig ships a vector editor and a 3D editor. In both, any property the document owns can be exposed as a control: a fill color, a stroke width, a node position, a transform channel, a modifier parameter.
Editing writes to the document. Tuning writes to the parameters, and the canvas draws the resolved result. The same file answers both.
Rig something an agent generated
An SVG, a composed HTML page or a bounded Three.js scene can each carry a rig declared in code. What a rig is covers the three pieces, and the examples are the worked versions.
Where this build stops
There is no account, no cloud project storage, no source write-back and no general-purpose code execution. None of it is behind a sign-up. It has not shipped.
Animation tracks cover top-level numeric values only. The hosted application serves the bundled examples: the connected-project workspace needs the local file service, which a static host does not run.