import { Compile } from "typebox/compile"; import type { TLocalizedValidationError } from "typebox/error"; import { Value } from "typebox/value"; import type { Tool, ToolCall } from "../types.ts"; const validatorCache = new WeakMap>(); const TYPEBOX_KIND = Symbol.for("TypeBox.Kind"); interface JsonSchemaObject { type?: string | string[]; properties?: Record; items?: JsonSchemaObject | JsonSchemaObject[]; additionalProperties?: boolean | JsonSchemaObject; allOf?: JsonSchemaObject[]; anyOf?: JsonSchemaObject[]; oneOf?: JsonSchemaObject[]; } function isRecord(value: unknown): value is Record { return typeof value === "object" && value !== null; } function isJsonSchemaObject(value: unknown): value is JsonSchemaObject { return isRecord(value); } function hasTypeBoxMetadata(schema: unknown): boolean { return isRecord(schema) && Object.getOwnPropertySymbols(schema).includes(TYPEBOX_KIND); } function getSchemaTypes(schema: JsonSchemaObject): string[] { if (typeof schema.type === "string") { return [schema.type]; } if (Array.isArray(schema.type)) { return schema.type.filter((type): type is string => typeof type === "string"); } return []; } function matchesJsonType(value: unknown, type: string): boolean { switch (type) { case "number": return typeof value === "number"; case "integer": return typeof value === "number" && Number.isInteger(value); case "boolean": return typeof value === "boolean"; case "string": return typeof value === "string"; case "null": return value === null; case "array": return Array.isArray(value); case "object": return isRecord(value) && !Array.isArray(value); default: return false; } } function isValidatorSchema(value: unknown): value is Tool["parameters"] { return isRecord(value); } function getSubSchemaValidator(schema: JsonSchemaObject): ReturnType | undefined { if (!isValidatorSchema(schema)) { return undefined; } try { return getValidator(schema); } catch { return undefined; } } function coercePrimitiveByType(value: unknown, type: string): unknown { switch (type) { case "number": { if (value === null) { return 0; } if (typeof value === "string" && value.trim() !== "") { const parsed = Number(value); if (Number.isFinite(parsed)) { return parsed; } } if (typeof value === "boolean") { return value ? 1 : 0; } return value; } case "integer": { if (value === null) { return 0; } if (typeof value === "string" && value.trim() !== "") { const parsed = Number(value); if (Number.isInteger(parsed)) { return parsed; } } if (typeof value === "boolean") { return value ? 1 : 0; } return value; } case "boolean": { if (value === null) { return false; } if (typeof value === "string") { if (value === "true") { return true; } if (value === "false") { return false; } } if (typeof value === "number") { if (value === 1) { return true; } if (value === 0) { return false; } } return value; } case "string": { if (value === null) { return ""; } if (typeof value === "number" || typeof value === "boolean") { return String(value); } return value; } case "null": { if (value === "" || value === 0 || value === false) { return null; } return value; } default: return value; } } function applySchemaObjectCoercion(value: Record, schema: JsonSchemaObject): void { const properties = schema.properties; const definedKeys = new Set(properties ? Object.keys(properties) : []); if (properties) { for (const [key, propertySchema] of Object.entries(properties)) { if (!(key in value)) { continue; } value[key] = coerceWithJsonSchema(value[key], propertySchema); } } if (schema.additionalProperties && isJsonSchemaObject(schema.additionalProperties)) { for (const [key, propertyValue] of Object.entries(value)) { if (definedKeys.has(key)) { continue; } value[key] = coerceWithJsonSchema(propertyValue, schema.additionalProperties); } } } function applySchemaArrayCoercion(value: unknown[], schema: JsonSchemaObject): void { if (Array.isArray(schema.items)) { for (let index = 0; index < value.length; index++) { const itemSchema = schema.items[index]; if (!itemSchema) { continue; } value[index] = coerceWithJsonSchema(value[index], itemSchema); } return; } if (isJsonSchemaObject(schema.items)) { for (let index = 0; index < value.length; index++) { value[index] = coerceWithJsonSchema(value[index], schema.items); } } } function coerceWithUnionSchema(value: unknown, schemas: JsonSchemaObject[]): unknown { for (const schema of schemas) { const candidate = structuredClone(value); const coerced = coerceWithJsonSchema(candidate, schema); const validator = getSubSchemaValidator(schema); if (validator?.Check(coerced)) { return coerced; } } return value; } function coerceWithJsonSchema(value: unknown, schema: JsonSchemaObject): unknown { let nextValue = value; if (Array.isArray(schema.allOf)) { for (const nested of schema.allOf) { nextValue = coerceWithJsonSchema(nextValue, nested); } } if (Array.isArray(schema.anyOf)) { nextValue = coerceWithUnionSchema(nextValue, schema.anyOf); } if (Array.isArray(schema.oneOf)) { nextValue = coerceWithUnionSchema(nextValue, schema.oneOf); } const schemaTypes = getSchemaTypes(schema); const matchesUnionMember = schemaTypes.length > 1 && schemaTypes.some((schemaType) => matchesJsonType(nextValue, schemaType)); if (schemaTypes.length > 0 && !matchesUnionMember) { for (const schemaType of schemaTypes) { const candidate = coercePrimitiveByType(nextValue, schemaType); if (candidate !== nextValue) { nextValue = candidate; break; } } } if (schemaTypes.includes("object") && isRecord(nextValue) && !Array.isArray(nextValue)) { applySchemaObjectCoercion(nextValue, schema); } if (schemaTypes.includes("array") && Array.isArray(nextValue)) { applySchemaArrayCoercion(nextValue, schema); } return nextValue; } function getValidator(schema: Tool["parameters"]): ReturnType { const key = schema as object; const cached = validatorCache.get(key); if (cached) { return cached; } const validator = Compile(schema); validatorCache.set(key, validator); return validator; } function formatValidationPath(error: TLocalizedValidationError): string { if (error.keyword === "required") { const requiredProperties = (error.params as { requiredProperties?: string[] }).requiredProperties; const requiredProperty = requiredProperties?.[0]; if (requiredProperty) { const basePath = error.instancePath.replace(/^\//, "").replace(/\//g, "."); return basePath ? `${basePath}.${requiredProperty}` : requiredProperty; } } const path = error.instancePath.replace(/^\//, "").replace(/\//g, "."); return path || "root"; } /** * Finds a tool by name and validates the tool call arguments against its TypeBox schema * @param tools Array of tool definitions * @param toolCall The tool call from the LLM * @returns The validated arguments * @throws Error if tool is not found or validation fails */ export function validateToolCall(tools: Tool[], toolCall: ToolCall): any { const tool = tools.find((t) => t.name === toolCall.name); if (!tool) { throw new Error(`Tool "${toolCall.name}" not found`); } return validateToolArguments(tool, toolCall); } /** * Validates tool call arguments against the tool's TypeBox schema * @param tool The tool definition with TypeBox schema * @param toolCall The tool call from the LLM * @returns The validated (and potentially coerced) arguments * @throws Error with formatted message if validation fails */ export function validateToolArguments(tool: Tool, toolCall: ToolCall): any { const args = structuredClone(toolCall.arguments); Value.Convert(tool.parameters, args); const validator = getValidator(tool.parameters); if (!hasTypeBoxMetadata(tool.parameters) && isJsonSchemaObject(tool.parameters)) { const coerced = coerceWithJsonSchema(args, tool.parameters); if (coerced !== args) { if (isRecord(args) && isRecord(coerced)) { for (const key of Object.keys(args)) { delete args[key]; } Object.assign(args, coerced); } else { return validator.Check(coerced) ? coerced : args; } } } if (validator.Check(args)) { return args; } const errors = validator .Errors(args) .map((error) => ` - ${formatValidationPath(error)}: ${error.message}`) .join("\n") || "Unknown validation error"; const errorMessage = `Validation failed for tool "${toolCall.name}":\n${errors}\n\nReceived arguments:\n${JSON.stringify(toolCall.arguments, null, 2)}`; throw new Error(errorMessage); }