Declarative Agent YAML: outputSchema loses nested object and array item properties in generated ResponseFormat

[KossiH]

Hi,

I’m running into an issue with Agent Framework declarative agent YAML when using nested objects and arrays in outputSchema.

After creating the agent with:

ChatClientPromptAgentFactory.CreateFromYamlAsync(yaml)

the generated ResponseFormat seems to drop the nested properties for sub-objects and array items, which makes them impossible to populate.

Agent YAML

kind: prompt
name: AssistantAgent
description: Helpful assistant
instructions: "You are a helpful assistant"
model:
  id: gpt-5.6-luna
outputSchema:
  type: object
  properties:
    rationale:
      type: record
      required: true
      properties:
        test:
          type: string
        test2:
          type: string
    results:
      type: table
      properties:
        id:
          type: string
        value:
          type: string

Actual generated ResponseFormat

{
  "type": "object",
  "properties": {
    "rationale": {
      "type": "object",
      "properties": {},
      "additionalProperties": false
    },
    "results": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {},
        "additionalProperties": false
      }
    }
  },
  "additionalProperties": false
}

Expected behavior

I would expect the generated ResponseFormat to preserve the nested schema definitions, something like:

{
  "type": "object",
  "properties": {
    "rationale": {
      "type": "object",
      "properties": {
        "test": {
          "type": "string"
        },
        "test2": {
          "type": "string"
        }
      },
      "additionalProperties": false
    },
    "results": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "id": {
            "type": "string"
          },
          "value": {
            "type": "string"
          }
        },
        "additionalProperties": false
      }
    }
  },
  "additionalProperties": false
}

Question

Is this currently a limitation/bug in the YAML-to-ResponseFormat conversion, or is there a different YAML syntax required for:

• nested object output schemas
• arrays of objects
• record / table types with child properties

In short: how should sub-objects and arrays be defined in declarative agent YAML so their properties survive into the generated ResponseFormat?

Thanks.

[Mohammad Rezwan Khan (mohammadrezwankhan)]

The nested fields need to be part of the structured type value. With the scalar shorthand type: record / type: table, the YAML reader creates a RecordDataType / TableDataType with an empty Properties collection; the sibling properties mapping is not used to populate that data type.

This shape preserves the children:

outputSchema:
  type: object
  properties:
    rationale:
      type:
        kind: record
        properties:
          test:
            type: string
          test2:
            type: string
      required: true
    results:
      type:
        kind: table
        properties:
          id:
            type: string
          value:
            type: string

table is the object-model representation that becomes an array of objects. Keep required alongside type; put the record/table properties inside the type mapping.

That also matches the current conversion path: PromptAgentExtensions passes OutputType to AsChatResponseFormat() (source); RecordDataTypeExtensions enumerates the record properties (source); and PropertyInfoExtensions recursively emits nested records and table item properties (source). In other words, the empty JSON objects are a symptom of the parsed data types being empty, rather than a limitation of the JSON-schema conversion.