Output schema 400 missing_items: an array node needs items
A Format output_schema with an array and no items fails with 400 and rule missing_items before anything runs. The bad schema, the fix, the violation.
If a Format run answers 400 output_schema_invalid and one of the entries in details.violations[] has the rule missing_items, you declared a node with "type": "array" and no items. Add an items schema to that array and send the request again. Sume checks the schema at submit, before anything runs, and charges nothing for the rejected call (Structured output).
Plain JSON Schema allows an array with no items, which means an array of anything. The strict subset that Sume enforces does not, because Sume only fills a schema it can satisfy mechanically.
Bad and fixed
The first schema is rejected. The second names the element type, so it passes the check.
// rejected: rule missing_items at #/properties/captions
{
"type": "object",
"additionalProperties": false,
"required": ["captions"],
"properties": { "captions": { "type": "array" } }
}
// accepted
{
"type": "object",
"additionalProperties": false,
"required": ["captions"],
"properties": { "captions": { "type": "array", "items": { "type": "string" } } }
}Read the rule, not the message
Each violation is { path, rule, message }. The path is a JSON-Pointer-style location such as #/properties/scenes/items/properties/clip. The message is text for a person and can change, while rule is a stable lowercase token you can switch on. Sume reports every problem in one response, so one 400 is usually enough to fix the whole schema.
| rule | What it flags |
|---|---|
| missing_items | An array node with no items. |
| missing_type | A node with no type, $ref or anyOf. |
| unsupported_type | A type outside the seven allowed types. |
| additional_properties_false | An object node without additionalProperties: false. |
| required_completeness | A declared property missing from required, or the reverse. |
If the items are objects
An items object is itself a node, so it needs additionalProperties: false, every property in required, and a type on each property. For repeated shapes, put the object under root $defs and point items at #/$defs/<name>. The same rules apply on a schedule, where you paste the schema into the dashboard, and on an Agent Completion.
Sources
Related posts
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