Function schema

packages/opencode/src/provider/transform.ts:1419–1559

(model: Provider.Model, schema: JSONSchema7)

}

export function schema(model: Provider.Model, schema: JSONSchema7): JSONSchema7 {
  /*
  if (["openai", "azure"].includes(providerID)) {
    if (schema.type === "object" && schema.properties) {
      for (const [key, value] of Object.entries(schema.properties)) {
        if (schema.required?.includes(key)) continue
        schema.properties[key] = {
          anyOf: [
            value as JSONSchema.JSONSchema,
            {
              type: "null",
            },
          ],
        }
      }
    }
  }
  */

  if (model.api.npm === "@ai-sdk/openai" || model.api.npm === "@ai-sdk/azure") {
    schema = sanitizeOpenAISchema(schema) as JSONSchema7
    // Codex also applies lossy compaction above 4 KB; defer that until OpenCode needs the same schema budget.
  }

  if (model.providerID === "moonshotai" || model.api.id.toLowerCase().includes("kimi")) {
    const sanitizeMoonshot = (obj: unknown): unknown => {
      if (obj === null || typeof obj !== "object") return obj
      if (Array.isArray(obj)) return obj.map(sanitizeMoonshot)
      // Moonshot expands $ref before validation and rejects sibling keywords like description on the same node.
      if ("$ref" in obj && typeof obj.$ref === "string") return { $ref: obj.$ref }
      const result = Object.fromEntries(Object.entries(obj).map(([key, value]) => [key, sanitizeMoonshot(value)]))
      // MFJS does not support tuple-style `items` arrays; it requires one schema object for all array items.
      if (Array.isArray(result.items)) result.items = result.items[0] ?? {}
      return result
    }

    const sanitized = sanitizeMoonshot(schema)
    if (typeof sanitized === "object" && sanitized !== null && !Array.isArray(sanitized)) {
      schema = sanitized
    }
  }

  // Convert integer enums to string enums for Google/Gemini
  if (model.providerID === "google" || model.api.id.includes("gemini")) {
    const isPlainObject = (node: unknown): node is Record<string, any> =>
      typeof node === "object" && node !== null && !Array.isArray(node)
    const hasCombiner = (node: unknown) =>
      isPlainObject(node) && (Array.isArray(node.anyOf) || Array.isArray(node.oneOf) || Array.isArray(node.allOf))
    const hasSchemaIntent = (node: unknown) => {
      if (!isPlainObject(node)) return false
      if (hasCombiner(node)) return true
      return [
        "type",
        "properties",
        "items",
        "prefixItems",
        "enum",
        "const",