From 6a7e2863832bc405faf5c63b376eb41c7f8382c3 Mon Sep 17 00:00:00 2001
From: Adam Perry <anp@openai.com>
Date: Thu, 25 Jun 2026 14:43:42 +0000
Subject: [PATCH] define schema breakage violations

---
 codex-rs/Cargo.lock                        |  1 +
 codex-rs/schema-evolution/Cargo.toml       |  1 +
 codex-rs/schema-evolution/src/lib.rs       |  3 +++
 codex-rs/schema-evolution/src/violation.rs | 26 ++++++++++++++++++++++
 4 files changed, 31 insertions(+)
 create mode 100644 codex-rs/schema-evolution/src/violation.rs

diff --git a/codex-rs/Cargo.lock b/codex-rs/Cargo.lock
index 78ff5bd62c..17bab1e24b 100644
--- a/codex-rs/Cargo.lock
+++ b/codex-rs/Cargo.lock
@@ -3844,6 +3844,7 @@ version = "0.0.0"
 dependencies = [
  "anyhow",
  "pretty_assertions",
+ "serde",
  "serde_json",
 ]
 
diff --git a/codex-rs/schema-evolution/Cargo.toml b/codex-rs/schema-evolution/Cargo.toml
index 9a4f50a078..3dc8e0247d 100644
--- a/codex-rs/schema-evolution/Cargo.toml
+++ b/codex-rs/schema-evolution/Cargo.toml
@@ -14,6 +14,7 @@ workspace = true
 
 [dependencies]
 anyhow = { workspace = true }
+serde = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true }
 
 [dev-dependencies]
diff --git a/codex-rs/schema-evolution/src/lib.rs b/codex-rs/schema-evolution/src/lib.rs
index 7f769f7996..c2e7c1a15c 100644
--- a/codex-rs/schema-evolution/src/lib.rs
+++ b/codex-rs/schema-evolution/src/lib.rs
@@ -1,5 +1,6 @@
 mod model;
 mod parse;
+mod violation;
 
 pub use model::ApiSchema;
 pub(crate) use model::Arguments;
@@ -14,3 +15,5 @@ pub(crate) use model::TypeSet;
 pub(crate) use model::UnionKind;
 pub(crate) use model::UnionSchema;
 pub(crate) use model::ValueSet;
+pub use violation::SchemaBreakage;
+pub use violation::ViolationKind;
diff --git a/codex-rs/schema-evolution/src/violation.rs b/codex-rs/schema-evolution/src/violation.rs
new file mode 100644
index 0000000000..60947a2718
--- /dev/null
+++ b/codex-rs/schema-evolution/src/violation.rs
@@ -0,0 +1,26 @@
+use serde::Deserialize;
+use serde::Serialize;
+use serde_json::Value;
+
+#[derive(Clone, Debug, Deserialize, Eq, Ord, PartialEq, PartialOrd, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub enum ViolationKind {
+    AdditionalPropertiesNarrowed,
+    ConstraintChanged,
+    EnumNarrowed,
+    MethodRemoved,
+    PropertyRemoved,
+    RequiredPropertyAdded,
+    TypeNarrowed,
+    UnionVariantRemoved,
+}
+
+#[derive(Clone, Debug, Eq, PartialEq, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SchemaBreakage {
+    pub kind: ViolationKind,
+    pub method: String,
+    pub path: String,
+    pub before: Value,
+    pub after: Value,
+}