> ## Documentation Index > Fetch the complete documentation index at: https://docs.tai42.ai/llms.txt > Use this file to discover all available pages before exploring further. # Schema forms > The schema-driven form renderer and the JSON Schema helpers it is built on. The schema-driven form renderer and the JSON Schema helpers it is built on. ## CompletionProvider ```ts theme={null} type CompletionProvider = (argName: string, partial: string) => Promise ``` Fetch argument-value suggestions for a string field. `argName` is the field's path within the form (a property key at the root, a dotted path when nested); `partial` is the value typed so far. The caller owns the source (e.g. an MCP `completion/complete` call) — SchemaForm only routes string fields through the completion-backed input when a provider is supplied. ## Discriminator ```ts theme={null} interface Discriminator ``` A Pydantic-style discriminated-union tag: which property selects the variant. **Properties** | Property | Type | Description | | -------------- | ---------------------------------- | ----------- | | `mapping?` | `Readonly>` | — | | `propertyName` | `string` | — | ## JsonSchema ```ts theme={null} interface JsonSchema ``` A structural JSON Schema node. All keys optional; the index signature keeps the type permissive so an unrecognized keyword is never a type error — it is a runtime classification concern the renderer handles. **Properties** | Property | Type | Description | | ----------------------- | --------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `$defs?` | `Readonly>` | — | | `$ref?` | `string` | — | | `additionalProperties?` | `boolean \| JsonSchema` | — | | `allOf?` | `readonly JsonSchema[]` | — | | `anyOf?` | `readonly JsonSchema[]` | — | | `const?` | `unknown` | — | | `contentEncoding?` | `string` | Media annotations (see the `SchemaForm` module). `contentEncoding: "base64"` together with `contentMediaType` (or `format: "data-url"`) opts a string field into the upload control; `contentMaxBytes` pins a per-field size cap. `contentMaxBytes` is a NONSTANDARD JSON-Schema extension keyword — a standard JSON-Schema validator ignores it. The client-side caps it drives (see the `media` module) are UX guards, NOT a security boundary: the SERVER MUST independently validate the decoded size of any uploaded content. | | `contentMaxBytes?` | `number` | — | | `contentMediaType?` | `string` | — | | `default?` | `unknown` | — | | `definitions?` | `Readonly>` | — | | `description?` | `string` | — | | `discriminator?` | `Discriminator` | — | | `enum?` | `readonly unknown[]` | — | | `format?` | `string` | — | | `items?` | `JsonSchema` | — | | `maxItems?` | `number` | — | | `maxLength?` | `number` | — | | `maximum?` | `number` | — | | `minItems?` | `number` | — | | `minLength?` | `number` | — | | `minimum?` | `number` | — | | `oneOf?` | `readonly JsonSchema[]` | — | | `properties?` | `Readonly>` | — | | `required?` | `readonly string[]` | — | | `title?` | `string` | — | | `type?` | `JsonSchemaType \| readonly JsonSchemaType[]` | — | **Related:** [Discriminator](/reference/studio-sdk/schema-forms#discriminator), [JsonSchemaType](/reference/studio-sdk/schema-forms#jsonschematype) ## JsonSchemaType ```ts theme={null} type JsonSchemaType = "string" | "number" | "integer" | "boolean" | "object" | "array" | "null" ``` The JSON-Schema `type` keyword values Pydantic emits. ## SchemaForm ```ts theme={null} function SchemaForm(props: SchemaFormProps): ReactNode ``` Render a controlled form for `schema`. The root is usually an object (a tool's input schema); a scalar/array/union root renders as a single field group. **Props** | Prop | Type | Description | | --------------------- | ---------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `completionProvider?` | `CompletionProvider` | Optional. When supplied, every string field renders through the completion-backed input (argument autocomplete); when omitted, string fields render as a plain text input — the default, unchanged behaviour. | | `errors?` | `Readonly>` | — | | `idPrefix?` | `string` | — | | `maxUploadBytes?` | `number` | Optional. Default byte cap for media-upload fields (see the module doc-comment). A field's own `contentMaxBytes` annotation overrides it; absent both, DEFAULT\_MAX\_UPLOAD\_BYTES applies. | | `onChange` | `(value: unknown) => void` | — | | `schema` | `JsonSchema` | — | | `value` | `unknown` | — | **Related:** [SchemaFormProps](/reference/studio-sdk/schema-forms#schemaformprops) ## SchemaFormErrors ```ts theme={null} type SchemaFormErrors = Readonly> ``` A structured, per-path bag of validation problems. Keys are dotted/bracketed paths from the form root (`""` = the root value, `"user.name"`, `"tags[0]"`); each entry is a loud, human-readable message. Empty object = valid. ## SchemaFormProps ```ts theme={null} interface SchemaFormProps ``` **Properties** | Property | Type | Description | | --------------------- | ---------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `completionProvider?` | `CompletionProvider` | Optional. When supplied, every string field renders through the completion-backed input (argument autocomplete); when omitted, string fields render as a plain text input — the default, unchanged behaviour. | | `errors?` | `Readonly>` | — | | `idPrefix?` | `string` | — | | `maxUploadBytes?` | `number` | Optional. Default byte cap for media-upload fields (see the module doc-comment). A field's own `contentMaxBytes` annotation overrides it; absent both, DEFAULT\_MAX\_UPLOAD\_BYTES applies. | | `onChange` | `(value: unknown) => void` | — | | `schema` | `JsonSchema` | — | | `value` | `unknown` | — | **Related:** [CompletionProvider](/reference/studio-sdk/schema-forms#completionprovider), [JsonSchema](/reference/studio-sdk/schema-forms#jsonschema) ## defaultValueForSchema ```ts theme={null} function defaultValueForSchema(schema: JsonSchema, root: JsonSchema): unknown ``` The initial value for a schema. `root` carries the `$defs` document for `$ref` resolution and defaults to the schema itself (the common whole-tool-schema call). **Parameters** | Parameter | Type | Default | Description | | --------- | ------------ | -------- | ----------- | | `schema` | `JsonSchema` | — | — | | `root` | `JsonSchema` | `schema` | — | **Related:** [JsonSchema](/reference/studio-sdk/schema-forms#jsonschema) ## resolveRef ```ts theme={null} function resolveRef(schema: JsonSchema, root: JsonSchema): JsonSchema ``` Resolve an internal `$ref` against the document root, following chained refs (a `$ref` whose target is itself a `$ref`). Only same-document pointers are supported (`#/$defs/Name`, `#/definitions/Name`, `#`); an external or unresolvable ref throws LOUDLY rather than yielding a silent empty schema. A schema with no `$ref` is returned unchanged. A pointer cycle throws. **Parameters** | Parameter | Type | Default | Description | | --------- | ------------ | ------- | ----------- | | `schema` | `JsonSchema` | — | — | | `root` | `JsonSchema` | — | — | **Related:** [JsonSchema](/reference/studio-sdk/schema-forms#jsonschema) ## validateAgainstSchema ```ts theme={null} function validateAgainstSchema( schema: JsonSchema, value: unknown, options?: ValidateOptions, ): SchemaFormErrors ``` Validate `value` against `schema`, returning a per-path error bag (empty = valid). The caller runs this before submit and feeds the result back to `SchemaForm` for display. `options.maxUploadBytes` mirrors the renderer's `maxUploadBytes` prop so a media field's byte cap is enforced identically here. **Parameters** | Parameter | Type | Default | Description | | ---------------------- | ----------------- | ------- | ----------- | | `schema` | `JsonSchema` | — | — | | `value` | `unknown` | — | — | | `options` *(optional)* | `ValidateOptions` | — | — | **Related:** [JsonSchema](/reference/studio-sdk/schema-forms#jsonschema), [SchemaFormErrors](/reference/studio-sdk/schema-forms#schemaformerrors)