From 73eaebbd1c8b463a4a8f92eacb88e8e76f865414 Mon Sep 17 00:00:00 2001
From: Rasmus Rygaard <rasmus@openai.com>
Date: Wed, 25 Feb 2026 11:17:38 -0800
Subject: [PATCH] Propagate session ID when compacting (#12802)

We propagate the session ID when sending requests for inference but we
don't do the same for compaction requests. This makes it hard to link
compaction requests to their session for debugging purposes
---
 codex-rs/core/src/client.rs                 |  5 ++++-
 codex-rs/core/tests/suite/compact_remote.rs | 13 +++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/codex-rs/core/src/client.rs b/codex-rs/core/src/client.rs
index 74a2f15c1..25de3d33e 100644
--- a/codex-rs/core/src/client.rs
+++ b/codex-rs/core/src/client.rs
@@ -315,7 +315,10 @@ impl ModelClient {
             instructions: &instructions,
         };
 
-        let extra_headers = self.build_subagent_headers();
+        let mut extra_headers = self.build_subagent_headers();
+        extra_headers.extend(build_conversation_headers(Some(
+            self.state.conversation_id.to_string(),
+        )));
         client
             .compact_input(&payload, extra_headers)
             .await
diff --git a/codex-rs/core/tests/suite/compact_remote.rs b/codex-rs/core/tests/suite/compact_remote.rs
index 1d450f9b1..573f38930 100644
--- a/codex-rs/core/tests/suite/compact_remote.rs
+++ b/codex-rs/core/tests/suite/compact_remote.rs
@@ -77,6 +77,7 @@ async fn remote_compact_replaces_history_for_followups() -> Result<()> {
     )
     .await?;
     let codex = harness.test().codex.clone();
+    let session_id = harness.test().session_configured.session_id.to_string();
 
     let responses_mock = responses::mount_sse_sequence(
         harness.server(),
@@ -137,6 +138,10 @@ async fn remote_compact_replaces_history_for_followups() -> Result<()> {
         compact_request.header("authorization").as_deref(),
         Some("Bearer Access Token")
     );
+    assert_eq!(
+        compact_request.header("session_id").as_deref(),
+        Some(session_id.as_str())
+    );
     let compact_body = compact_request.body_json();
     assert_eq!(
         compact_body.get("model").and_then(|v| v.as_str()),
@@ -195,6 +200,7 @@ async fn remote_compact_runs_automatically() -> Result<()> {
     )
     .await?;
     let codex = harness.test().codex.clone();
+    let session_id = harness.test().session_configured.session_id.to_string();
 
     mount_sse_once(
         harness.server(),
@@ -237,6 +243,13 @@ async fn remote_compact_runs_automatically() -> Result<()> {
     wait_for_event(&codex, |event| matches!(event, EventMsg::TurnComplete(_))).await;
     assert!(message);
     assert_eq!(compact_mock.requests().len(), 1);
+    assert_eq!(
+        compact_mock
+            .single_request()
+            .header("session_id")
+            .as_deref(),
+        Some(session_id.as_str())
+    );
     let follow_up_request = responses_mock.single_request();
     let follow_up_body = follow_up_request.body_json().to_string();
     assert!(follow_up_body.contains("REMOTE_COMPACTED_SUMMARY"));