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fix json schema properties translations for anthropic #190

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Merged
Ken Jiang (knjiang) merged 3 commits into from
Apr 13, 2026
Merged

fix json schema properties translations for anthropic #190

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6aa40c8
fix json schema properties
knjiang Apr 13, 2026
f668070
fix names
knjiang Apr 13, 2026
ed07155
fixxx
knjiang Apr 13, 2026
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92 changes: 92 additions & 0 deletions crates/coverage-report/src/requests_expected_differences.json
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Original file line number Diff line number Diff line change
Expand Up @@ -388,6 +388,98 @@
{ "pattern": "params.response_format.json_schema.schema.propertyOrdering", "reason": "Google propertyOrdering is a Google-only schema hint and is stripped for non-Google strict-schema targets" }
]
},
{
"testCase": "jsonSchemaPrefixItemsParam",
"source": "*",
"target": "Anthropic",
"fields": [
{ "pattern": "params.response_format.json_schema.schema.properties.tuple.prefixItems", "reason": "Anthropic structured outputs drop tuple-position hints during lossy schema normalization" },
{ "pattern": "params.response_format.json_schema.schema.properties.tuple.minItems", "reason": "Anthropic structured outputs drop array length bounds during lossy schema normalization" },
{ "pattern": "params.response_format.json_schema.schema.properties.tuple.maxItems", "reason": "Anthropic structured outputs drop array length bounds during lossy schema normalization" }
]
},
{
"testCase": "jsonSchemaPrefixItemsParam",
"source": "Google",
"target": "ChatCompletions",
"fields": [
{ "pattern": "params.response_format.json_schema.schema.additionalProperties", "reason": "Strict OpenAI-style targets require explicit closed object schemas when Google omits additionalProperties" }
]
},
{
"testCase": "jsonSchemaPrefixItemsParam",
"source": "Google",
"target": "Responses",
"fields": [
{ "pattern": "params.response_format.json_schema.schema.additionalProperties", "reason": "Strict OpenAI-style targets require explicit closed object schemas when Google omits additionalProperties" }
]
},
{
"testCase": "jsonSchemaFormatParam",
"source": "Google",
"target": "ChatCompletions",
"fields": [
{ "pattern": "params.response_format.json_schema.schema.additionalProperties", "reason": "Strict OpenAI-style targets require explicit closed object schemas when Google omits additionalProperties" }
]
},
{
"testCase": "jsonSchemaFormatParam",
"source": "Google",
"target": "Responses",
"fields": [
{ "pattern": "params.response_format.json_schema.schema.additionalProperties", "reason": "Strict OpenAI-style targets require explicit closed object schemas when Google omits additionalProperties" }
]
},
{
"testCase": "jsonSchemaMinMaxItemsParam",
"source": "*",
"target": "Anthropic",
"fields": [
{ "pattern": "params.response_format.json_schema.schema.properties.tags.minItems", "reason": "Anthropic structured outputs drop array length bounds during lossy schema normalization" },
{ "pattern": "params.response_format.json_schema.schema.properties.tags.maxItems", "reason": "Anthropic structured outputs drop array length bounds during lossy schema normalization" }
]
},
{
"testCase": "jsonSchemaMinMaxItemsParam",
"source": "Google",
"target": "ChatCompletions",
"fields": [
{ "pattern": "params.response_format.json_schema.schema.additionalProperties", "reason": "Strict OpenAI-style targets require explicit closed object schemas when Google omits additionalProperties" }
]
},
{
"testCase": "jsonSchemaMinMaxItemsParam",
"source": "Google",
"target": "Responses",
"fields": [
{ "pattern": "params.response_format.json_schema.schema.additionalProperties", "reason": "Strict OpenAI-style targets require explicit closed object schemas when Google omits additionalProperties" }
]
},
{
"testCase": "jsonSchemaMinimumMaximumParam",
"source": "*",
"target": "Anthropic",
"fields": [
{ "pattern": "params.response_format.json_schema.schema.properties.score.minimum", "reason": "Anthropic structured outputs drop numeric bounds during lossy schema normalization" },
{ "pattern": "params.response_format.json_schema.schema.properties.score.maximum", "reason": "Anthropic structured outputs drop numeric bounds during lossy schema normalization" }
]
},
{
"testCase": "jsonSchemaMinimumMaximumParam",
"source": "Google",
"target": "ChatCompletions",
"fields": [
{ "pattern": "params.response_format.json_schema.schema.additionalProperties", "reason": "Strict OpenAI-style targets require explicit closed object schemas when Google omits additionalProperties" }
]
},
{
"testCase": "jsonSchemaMinimumMaximumParam",
"source": "Google",
"target": "Responses",
"fields": [
{ "pattern": "params.response_format.json_schema.schema.additionalProperties", "reason": "Strict OpenAI-style targets require explicit closed object schemas when Google omits additionalProperties" }
]
},
{
"testCase": "thinkingLevelParam",
"source": "Google",
Expand Down
50 changes: 50 additions & 0 deletions crates/lingua/src/providers/anthropic/convert.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1381,6 +1381,14 @@ impl TryFrom<&ResponseFormatConfig> for JsonOutputFormat {
field: "json_schema".to_string(),
}
})?;
// Anthropic's structured-output schema subset is narrower than
// the cross-provider JSON-schema surface. When we emit a typed
// `output_config.format` from canonical `response_format`, we
// intentionally drop tuple-position hints plus array/numeric
// bounds as a lossy compatibility fallback. Callers should not
// expect strict schema fidelity for `prefixItems`, `minItems`,
// `maxItems`, `minimum`, or `maximum`. Raw Anthropic
// `output_config` passthrough remains verbatim in adapter.rs.
match normalize_response_schema_for_strict_target(
&js.schema,
ProviderFormat::Anthropic,
Expand Down Expand Up @@ -1567,6 +1575,48 @@ mod tests {
);
}

#[test]
fn test_json_schema_response_format_to_anthropic_is_lossy_for_unsupported_keywords() {
let config = ResponseFormatConfig {
format_type: Some(ResponseFormatType::JsonSchema),
json_schema: Some(JsonSchemaConfig {
name: "response".to_string(),
schema: json!({
"type": "object",
"properties": {
"tuple": {
"type": "array",
"prefixItems": [
{ "type": "string" },
{ "type": "integer" }
],
"minItems": 2,
"maxItems": 2
},
"score": {
"type": "integer",
"minimum": 0,
"maximum": 10
}
},
"required": ["tuple", "score"],
"additionalProperties": false
}),
strict: Some(true),
description: None,
}),
};

let format = JsonOutputFormat::try_from(&config).unwrap();
let schema = Value::Object(format.schema);

assert_eq!(schema.pointer("/properties/tuple/prefixItems"), None);
assert_eq!(schema.pointer("/properties/tuple/minItems"), None);
assert_eq!(schema.pointer("/properties/tuple/maxItems"), None);
assert_eq!(schema.pointer("/properties/score/minimum"), None);
assert_eq!(schema.pointer("/properties/score/maximum"), None);
}

#[test]
fn test_google_search_builtin_maps_to_anthropic_web_search() {
let tool = UniversalTool::builtin(
Expand Down
87 changes: 86 additions & 1 deletion crates/lingua/src/universal/response_format.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,7 @@ use crate::error::ConvertError;
use crate::processing::transform::TransformError;
use crate::providers::anthropic::generated::JsonOutputFormat;
use crate::providers::google::generated::GenerationConfig;
use crate::serde_json::{self, json, Map, Value};
use crate::serde_json::{self, json, Map, Number, Value};
use crate::universal::request::{JsonSchemaConfig, ResponseFormatConfig, ResponseFormatType};
use serde::{Deserialize, Serialize};

Expand Down Expand Up @@ -97,6 +97,13 @@ enum AdditionalPropertiesNormalizationView {
Other(Value),
}

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(untagged)]
enum SchemaScalarConstraintView {
Number(Number),
String(String),
Other(Value),
}
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
struct StrictTargetSchemaNodeView {
#[serde(rename = "type", default, skip_serializing_if = "Option::is_none")]
Expand All @@ -113,6 +120,35 @@ struct StrictTargetSchemaNodeView {
skip_serializing_if = "Option::is_none"
)]
property_ordering: Option<Vec<String>>,
#[serde(rename = "minItems", default, skip_serializing_if = "Option::is_none")]
min_items: Option<SchemaScalarConstraintView>,
#[serde(rename = "maxItems", default, skip_serializing_if = "Option::is_none")]
max_items: Option<SchemaScalarConstraintView>,
#[serde(rename = "minimum", default, skip_serializing_if = "Option::is_none")]
minimum: Option<SchemaScalarConstraintView>,
#[serde(rename = "maximum", default, skip_serializing_if = "Option::is_none")]
maximum: Option<SchemaScalarConstraintView>,
}

/// Anthropic structured outputs accept a narrower JSON Schema subset than the
/// cross-provider canonical format. When targeting Anthropic we intentionally
/// narrow the schemas by dropping unsupported tuple hints and array/numeric bounds.
fn strip_anthropic_unsupported_schema_keywords(
map: &mut Map<String, Value>,
node: &StrictTargetSchemaNodeView,
) {
match node.schema_type.as_deref() {
Some("array") => {
map.remove("prefixItems");
map.remove("minItems");
map.remove("maxItems");
}
Some("integer") | Some("number") => {
map.remove("minimum");
map.remove("maximum");
}
_ => {}
}
}

pub(crate) fn normalize_response_schema_for_strict_target(
Expand All @@ -134,6 +170,10 @@ pub(crate) fn normalize_response_schema_for_strict_target(
})?;

if let Value::Object(map) = value {
if target_provider == ProviderFormat::Anthropic {
strip_anthropic_unsupported_schema_keywords(map, &node);
}

if node.schema_type.as_deref() == Some("object") {
if target_provider != ProviderFormat::Google {
map.remove("propertyOrdering");
Expand Down Expand Up @@ -728,6 +768,51 @@ mod tests {
);
}

#[test]
fn test_anthropic_lossy_normalization_strips_array_and_numeric_bounds() {
let schema = json!({
"type": "object",
"properties": {
"tuple": {
"type": "array",
"prefixItems": [
{ "type": "string" },
{ "type": "integer" }
],
"minItems": 2,
"maxItems": 3,
"items": { "type": "string" }
},
"score": {
"type": "integer",
"minimum": 0,
"maximum": 10
}
}
});

let anthropic =
normalize_response_schema_for_strict_target(&schema, ProviderFormat::Anthropic)
.unwrap();
assert_eq!(anthropic.pointer("/properties/tuple/prefixItems"), None);
assert_eq!(anthropic.pointer("/properties/tuple/minItems"), None);
assert_eq!(anthropic.pointer("/properties/tuple/maxItems"), None);
assert_eq!(anthropic.pointer("/properties/score/minimum"), None);
assert_eq!(anthropic.pointer("/properties/score/maximum"), None);

let chat =
normalize_response_schema_for_strict_target(&schema, ProviderFormat::ChatCompletions)
.unwrap();
assert_eq!(
chat.pointer("/properties/tuple/prefixItems/0/type"),
Some(&Value::String("string".to_string()))
);
assert_eq!(chat.pointer("/properties/tuple/minItems"), Some(&json!(2)));
assert_eq!(chat.pointer("/properties/tuple/maxItems"), Some(&json!(3)));
assert_eq!(chat.pointer("/properties/score/minimum"), Some(&json!(0)));
assert_eq!(chat.pointer("/properties/score/maximum"), Some(&json!(10)));
}

#[test]
fn test_strict_target_rejects_explicit_additional_properties_true() {
let config = ResponseFormatConfig {
Expand Down
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