diff --git a/codex-rs/core/tests/suite/client.rs b/codex-rs/core/tests/suite/client.rs
index 61429b2dfc..40664679f5 100644
--- a/codex-rs/core/tests/suite/client.rs
+++ b/codex-rs/core/tests/suite/client.rs
@@ -901,7 +901,6 @@ async fn history_dedupes_streamed_and_final_messages_across_turns() {
     let requests = server.received_requests().await.unwrap();
     assert_eq!(requests.len(), 3, "expected 3 requests (one per turn)");
 
-    // Replace full-array compare with tail-only raw JSON compare using a single hard-coded value.
     let r3_input_array = requests[2]
         .body_json::<serde_json::Value>()
         .unwrap()
@@ -909,60 +908,39 @@ async fn history_dedupes_streamed_and_final_messages_across_turns() {
         .and_then(|v| v.as_array())
         .cloned()
         .expect("r3 missing input array");
-    // We only assert on the last 5 items of the input history for request 3.
-    // With per-turn environment context injected, the last 5 should be:
-    // [env_ctx, U2, assistant("Hey there!\n"), env_ctx, U3]
-    let actual_tail = &r3_input_array[r3_input_array.len() - 5..];
 
-    // env_ctx 1
-    assert_eq!(actual_tail[0]["type"], serde_json::json!("message"));
-    assert_eq!(actual_tail[0]["role"], serde_json::json!("user"));
-    let env_text_1 = &actual_tail[0]["content"][0]["text"];
-    assert!(
-        env_text_1
-            .as_str()
-            .expect("env text should be string")
-            .contains("<environment_context>")
-    );
-
-    // U2
-    assert_eq!(
-        actual_tail[1],
-        serde_json::json!({
+    // Assert on the last five messages of the input history for request 3.
+    // We expect the conversation tail to be [U1, A, U2, A, U3], skipping earlier context and developer messages.
+    let r3_tail_expected = serde_json::json!([
+        {
             "type": "message",
             "role": "user",
-            "content": [ { "type": "input_text", "text": "U2" } ]
-        })
-    );
-
-    // assistant response
-    assert_eq!(
-        actual_tail[2],
-        serde_json::json!({
+            "content": [{"type":"input_text","text":"U1"}]
+        },
+        {
             "type": "message",
             "role": "assistant",
-            "content": [ { "type": "output_text", "text": "Hey there!\n" } ]
-        })
-    );
-
-    // env_ctx 2
-    assert_eq!(actual_tail[3]["type"], serde_json::json!("message"));
-    assert_eq!(actual_tail[3]["role"], serde_json::json!("user"));
-    let env_text_2 = &actual_tail[3]["content"][0]["text"];
-    assert!(
-        env_text_2
-            .as_str()
-            .expect("env text should be string")
-            .contains("<environment_context>")
-    );
-
-    // U3
-    assert_eq!(
-        actual_tail[4],
-        serde_json::json!({
+            "content": [{"type":"output_text","text":"Hey there!\n"}]
+        },
+        {
             "type": "message",
             "role": "user",
-            "content": [ { "type": "input_text", "text": "U3" } ]
-        })
-    );
+            "content": [{"type":"input_text","text":"U2"}]
+        },
+        {
+            "type": "message",
+            "role": "assistant",
+            "content": [{"type":"output_text","text":"Hey there!\n"}]
+        },
+        {
+            "type": "message",
+            "role": "user",
+            "content": [{"type":"input_text","text":"U3"}]
+        }
+    ]);
+
+    // skipping earlier context and developer messages
+    let tail_len = r3_tail_expected.as_array().unwrap().len();
+    let actual_tail = &r3_input_array[r3_input_array.len() - tail_len..];
+    assert_eq!(serde_json::json!(actual_tail), r3_tail_expected);
 }