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celia-oai merged 5 commits into from
Jun 8, 2026
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Merged

feat: support oneOf and allOf in tool input schemas #24118

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celia-oai May 22, 2026
b8d1742
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celia-oai May 22, 2026
2a0eef2
Merge branch 'main' into dev/cc/support-allof
celia-oai May 22, 2026
8886e85
Merge branch 'main' into dev/cc/support-allof
celia-oai Jun 1, 2026
6c65c27
Merge branch 'main' into dev/cc/support-allof
celia-oai Jun 8, 2026
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65 changes: 59 additions & 6 deletions codex-rs/tools/src/json_schema.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -6,13 +6,15 @@ use std::collections::BTreeMap;
use std::collections::BTreeSet;

const DEFINITION_TABLE_KEYS: [&str; 2] = ["$defs", "definitions"];
const SCHEMA_CHILD_KEYS: [&str; 2] = ["items", "anyOf"];
const SCHEMA_CHILD_KEYS: [&str; 4] = ["items", "anyOf", "oneOf", "allOf"];
const COMPOSITION_SCHEMA_KEYS: [&str; 3] = ["anyOf", "oneOf", "allOf"];

/// Primitive JSON Schema type names we support in tool definitions.
///
/// This mirrors the OpenAI Structured Outputs subset for JSON Schema `type`:
/// string, number, boolean, integer, object, array, and null.
/// Keywords such as `enum`, `const`, and `anyOf` are modeled separately.
/// Keywords such as `enum`, `const`, `anyOf`, `oneOf`, and `allOf` are modeled
/// separately.
/// See <https://developers.openai.com/api/docs/guides/structured-outputs#supported-schemas>.
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "lowercase")]
Expand Down Expand Up @@ -61,6 +63,10 @@ pub struct JsonSchema {
pub additional_properties: Option<AdditionalProperties>,
#[serde(rename = "anyOf", skip_serializing_if = "Option::is_none")]
pub any_of: Option<Vec<JsonSchema>>,
#[serde(rename = "oneOf", skip_serializing_if = "Option::is_none")]
pub one_of: Option<Vec<JsonSchema>>,
#[serde(rename = "allOf", skip_serializing_if = "Option::is_none")]
pub all_of: Option<Vec<JsonSchema>>,
#[serde(rename = "$defs", skip_serializing_if = "Option::is_none")]
pub defs: Option<BTreeMap<String, JsonSchema>>,
#[serde(skip_serializing_if = "Option::is_none")]
Expand All @@ -85,6 +91,22 @@ impl JsonSchema {
}
}

pub fn one_of(variants: Vec<JsonSchema>, description: Option<String>) -> Self {
Self {
description,
one_of: Some(variants),
..Default::default()
}
}

pub fn all_of(variants: Vec<JsonSchema>, description: Option<String>) -> Self {
Self {
description,
all_of: Some(variants),
..Default::default()
}
}

pub fn boolean(description: Option<String>) -> Self {
Self::typed(JsonSchemaPrimitiveType::Boolean, description)
}
Expand Down Expand Up @@ -219,6 +241,7 @@ const LARGE_SCHEMA_COMPACTION_PASSES: &[LargeSchemaCompactionPass] = &[
strip_schema_descriptions,
drop_schema_definitions,
collapse_deep_schema_objects_from_root,
prune_schema_compositions,
];

fn collapse_deep_schema_objects_from_root(value: &mut JsonValue) {
Expand Down Expand Up @@ -397,17 +420,44 @@ fn collapse_deep_schema_objects(value: &mut JsonValue, depth: usize) {
}
}

fn prune_schema_compositions(value: &mut JsonValue) {
match value {
JsonValue::Array(values) => {
for value in values {
prune_schema_compositions(value);
}
}
JsonValue::Object(map) => {
if has_composition_keyword(map) {
*value = json!({});
return;
}

for_each_schema_child_mut(map, DefinitionTraversal::Skip, &mut |value| {
prune_schema_compositions(value);
});
}
_ => {}
}
}

fn is_complex_schema_object(map: &serde_json::Map<String, JsonValue>) -> bool {
SCHEMA_CHILD_KEYS.iter().any(|key| map.contains_key(*key))
|| map.contains_key("properties")
|| map.contains_key("additionalProperties")
|| map.contains_key("$ref")
}

fn has_composition_keyword(map: &serde_json::Map<String, JsonValue>) -> bool {
COMPOSITION_SCHEMA_KEYS
.into_iter()
.any(|key| map.contains_key(key))
}

/// Sanitize a JSON Schema (as serde_json::Value) so it can fit our limited
/// schema representation. This function:
/// - Ensures every typed schema object has a `"type"` when required.
/// - Preserves explicit `anyOf`.
/// - Preserves explicit `anyOf`, `oneOf`, and `allOf`.
/// - Preserves `$ref` and reachable local `$defs` / `definitions`.
/// - Collapses `const` into single-value `enum`.
/// - Fills required child fields for object/array schema types, including
Expand Down Expand Up @@ -443,8 +493,10 @@ fn sanitize_json_schema(value: &mut JsonValue) {
if let Some(value) = map.get_mut("prefixItems") {
sanitize_json_schema(value);
}
if let Some(value) = map.get_mut("anyOf") {
sanitize_json_schema(value);
for key in COMPOSITION_SCHEMA_KEYS {
if let Some(value) = map.get_mut(key) {
sanitize_json_schema(value);
}
}
for table in DEFINITION_TABLE_KEYS {
sanitize_schema_table(map, table);
Expand All @@ -456,7 +508,8 @@ fn sanitize_json_schema(value: &mut JsonValue) {

let mut schema_types = normalized_schema_types(map);

if schema_types.is_empty() && (map.contains_key("$ref") || map.contains_key("anyOf")) {
if schema_types.is_empty() && (map.contains_key("$ref") || has_composition_keyword(map))
{
return;
}

Expand Down
202 changes: 202 additions & 0 deletions codex-rs/tools/src/json_schema_tests.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -728,6 +728,109 @@ fn parse_tool_input_schema_preserves_nested_any_of_property() {
);
}

#[test]
fn parse_tool_input_schema_preserves_nested_one_of_property() {
// Example schema shape:
// {
// "type": "object",
// "properties": {
// "query": {
// "oneOf": [
// { "const": "exact" },
// { "type": "number" }
// ]
// }
// }
// }
//
// Expected normalization behavior:
// - The nested `oneOf` is preserved.
// - Child variants are recursively sanitized, including `const` to `enum`.
let schema = parse_tool_input_schema(&serde_json::json!({
"type": "object",
"properties": {
"query": {
"oneOf": [
{ "const": "exact" },
{ "type": "number" }
]
}
}
}))
.expect("parse schema");

assert_eq!(
schema,
JsonSchema::object(
BTreeMap::from([(
"query".to_string(),
JsonSchema::one_of(
vec![
JsonSchema::string_enum(
vec![serde_json::json!("exact")],
/*description*/ None,
),
JsonSchema::number(/*description*/ None),
],
/*description*/ None,
),
)]),
/*required*/ None,
/*additional_properties*/ None
)
);
}

#[test]
fn parse_tool_input_schema_preserves_nested_all_of_property() {
// Example schema shape:
// {
// "type": "object",
// "properties": {
// "query": {
// "allOf": [
// { "type": "string" },
// { "description": "unrecognized by itself" }
// ]
// }
// }
// }
//
// Expected normalization behavior:
// - The nested `allOf` is preserved structurally rather than flattened.
// - Child variants are recursively sanitized.
let schema = parse_tool_input_schema(&serde_json::json!({
"type": "object",
"properties": {
"query": {
"allOf": [
{ "type": "string" },
{ "description": "unrecognized by itself" }
]
}
}
}))
.expect("parse schema");

assert_eq!(
schema,
JsonSchema::object(
BTreeMap::from([(
"query".to_string(),
JsonSchema::all_of(
vec![
JsonSchema::string(/*description*/ None),
JsonSchema::default(),
],
/*description*/ None,
),
)]),
/*required*/ None,
/*additional_properties*/ None
)
);
}

#[test]
fn parse_tool_input_schema_preserves_type_unions_without_rewriting_to_any_of() {
// Example schema shape:
Expand Down Expand Up @@ -1070,6 +1173,77 @@ fn parse_large_tool_input_schema_strips_descriptions_without_removing_descriptio
);
}

#[test]
fn parse_large_tool_input_schema_prunes_compositions_as_last_resort() {
for composition_key in super::COMPOSITION_SCHEMA_KEYS {
let variants = vec![
serde_json::json!({
"type": "string",
"enum": ["first ".repeat(400)]
}),
serde_json::json!({
"type": "string",
"enum": ["second ".repeat(400)]
}),
serde_json::json!({
"type": "string",
"enum": ["third ".repeat(400)]
}),
];

let mut choice = serde_json::Map::new();
choice.insert(
composition_key.to_string(),
serde_json::Value::Array(variants),
);
let schema = parse_tool_input_schema(&serde_json::json!({
"type": "object",
"properties": {
"choice": choice
}
}))
.expect("parse schema");

assert_eq!(
serde_json::to_value(schema).expect("serialize schema"),
serde_json::json!({
"type": "object",
"properties": {
"choice": {}
}
})
);
}
}

#[test]
fn parse_large_tool_input_schema_prunes_single_composition_variant_if_still_over_budget() {
let schema = parse_tool_input_schema(&serde_json::json!({
"type": "object",
"properties": {
"choice": {
"anyOf": [
{
"type": "string",
"enum": ["x".repeat(4_500)]
}
]
}
}
}))
.expect("parse schema");

assert_eq!(
serde_json::to_value(schema).expect("serialize schema"),
serde_json::json!({
"type": "object",
"properties": {
"choice": {}
}
})
);
}

#[test]
fn parse_large_tool_input_schema_preserves_object_enum_literal_descriptions() {
let schema = parse_tool_input_schema(&serde_json::json!({
Expand Down Expand Up @@ -1397,10 +1571,24 @@ fn parse_tool_input_schema_collects_refs_from_schema_child_keywords() {
{"$ref": "#/$defs/Choice"},
{"type": "string"}
]
},
"exclusive_choice": {
"oneOf": [
{"$ref": "#/$defs/ExclusiveChoice"},
{"type": "integer"}
]
},
"combined": {
"allOf": [
{"$ref": "#/$defs/Combined"},
{"type": "object"}
]
}
},
"$defs": {
"Combined": {"type": "object"},
"Choice": {"type": "boolean"},
"ExclusiveChoice": {"type": "null"},
"Extra": {"type": "number"},
"Item": {"type": "string"},
"Unused": {"type": "null"}
Expand All @@ -1419,6 +1607,18 @@ fn parse_tool_input_schema_collects_refs_from_schema_child_keywords() {
{"type": "string"}
]
},
"combined": {
"allOf": [
{"$ref": "#/$defs/Combined"},
{"type": "object", "properties": {}}
]
},
"exclusive_choice": {
"oneOf": [
{"$ref": "#/$defs/ExclusiveChoice"},
{"type": "integer"}
]
},
"items_holder": {
"type": "array",
"items": {"$ref": "#/$defs/Item"}
Expand All @@ -1430,7 +1630,9 @@ fn parse_tool_input_schema_collects_refs_from_schema_child_keywords() {
}
},
"$defs": {
"Combined": {"type": "object", "properties": {}},
"Choice": {"type": "boolean"},
"ExclusiveChoice": {"type": "null"},
"Extra": {"type": "number"},
"Item": {"type": "string"}
}
Expand Down
13 changes: 9 additions & 4 deletions codex-rs/tools/tests/fixtures/json_schema_policy/google_drive.json
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Original file line number Diff line number Diff line change
Expand Up @@ -53,13 +53,18 @@
{
"pointer": "/properties/title/description",
"value": "Copied file title."
},
{
"pointer": "/properties/file/oneOf/0/type",
"value": "string"
},
{
"pointer": "/properties/metadata/allOf/0/properties/source/type",
"value": "string"
}
],
"expected_pruned": [],
"expected_dropped_fields": [
"/properties/file/oneOf",
"/properties/metadata/allOf"
]
"expected_dropped_fields": []
}
]
}
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