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prefixItems

Category: Keyword — presence of a specific JSON Schema keyword triggers this rule

Error Codes​

ProfileCode
openai.so.2026-04-30OAI-K-prefixItems
anthropic.so.2026-04-30ANT-K-prefixItems

Description​

Flag usage of the 'prefixItems' keyword, which is discouraged by openai.so.2026-04-30

Rationale​

The openai.so.2026-04-30 structured-output provider discourages use of the 'prefixItems' keyword. Schemas using this keyword may be rejected or silently altered.

Bad Example​

{ "type": "object", "prefixItems": true, "properties": {} }

Good Example​

{
  "type": "object",
  "properties": {
    "name": { "type": "string" }
  }
}