unknown-keyword
Category: Structural — overall schema structure triggers this rule
Error Codes
| Profile | Code | Severity |
|---|---|---|
| openai.so.2026-04-30 | OAI-S-unknown-keyword | Warn |
| anthropic.so.2026-04-30 | ANT-S-unknown-keyword | Warn |
Description
Flag a keyword the engine does not recognize at all
Provider Evidence
| Profile | Status | Source | Basis |
|---|---|---|---|
| anthropic.so.2026-04-30 | inferred | Anthropic JSON Schema limitations | Unknown keywords are outside the documented supported subset. |
| openai.so.2026-04-30 | inferred | OpenAI supported schemas | Unknown keywords are not covered by the documented supported subset. |
Rationale
schemalint knows a fixed set of JSON Schema keywords. A keyword outside that set was never checked against provider behavior, so schemalint cannot say whether the provider accepts, ignores, or rejects it.
Bad Example
{ "type": "string", "contentEncoding": "base64" }
Good Example
{ "type": "string" }