Tools

createGenUITools returns a set of tool definitions the model can call to read and mutate a JSON UI spec.

createGenUITools(options)

Creates tools that operate on a spec with shape { root, elements }. Options:

Option	Required	Description
contextId	Yes	String key for the current conversation/context
getSpec(contextId)	Yes	Return current spec or null
updateSpec(contextId, spec)	Yes	Persist the updated spec
toolWrapper(toolName, execute)	Yes	Wrapper for every tool execution (logging, error handling, telemetry)
createId	No	Id factory for new nodes (default: generates UI-{timestamp}-{random})
rootId	No	Root node id (default: "root")
nodeHints	No	Override component registry used in prompts
nodeNamesThatSupportChildren	No	Override list of node types that can have children

Tool list

• getUIRootNode — Return the root node id and element
• getUINode — Return a node by id
• getUILayout — Return layout (root + children structure)
• getAvailableUINodes — List available node types and hints
• setUINodeProps — Set props on a node ({ id, props, replace? }; default merge, use replace: true to replace all)
• deleteUINode — Remove a node
• addUINode — Add a node ({ parentId?, type, props? }; omit parentId to use root)
• reorderUINodes — Move a sibling by index (nodeId, offset; negative = earlier, positive = later; clamped to valid range)

All mutations are serialized so concurrent tool calls do not interleave writes.

buildGenUISystemPrompt(options?)

Builds the reusable system instructions for JSON UI tooling. Use as the system option for streamText / generateText.

Options:

Option	Default	Description
additionalInstructions	—	App-specific text appended to the prompt
requireLayoutReadBeforeAddingNodes	true	Whether to instruct the model to read layout before adding nodes
styleHints	—	Override style metadata used in the prompt text

Example:

system: buildGenUISystemPrompt({
  additionalInstructions:
    'Your name is John. Prefer short labels. Use Button for primary actions only.',
  styleHints: {
    borderRadius: { type: 'number', description: 'Border radius in px.' },
  },
})