From 829c2c115d739ccbc6d032383ad4dfd20f4e9a19 Mon Sep 17 00:00:00 2001
From: M3gA-Mind <elvin@tinyhumans.ai>
Date: Fri, 23 Oct 2026 06:02:00 +0530
Subject: [PATCH 1/2] fix(openai): folded system messages keep their JSON
 blocks

`single_system_message` and `merge_system_into_user` gathered system
content with a text-only helper that dropped JSON blocks and joined blocks
with a newline. The pass-through path (`translate_text_content`) serializes
JSON blocks and joins blocks with nothing between them, so a prompt sent to a
hoisting or merging endpoint differed from the same prompt sent as-is, and
lost any structured block. Render folded system content the same way.
---
 .../src/providers/openai/mod_tests.rs         | 25 +++++++++++++++++++
 .../src/providers/openai/transport.rs         | 13 ++++++----
 2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/crates/tinyinference-llm/src/providers/openai/mod_tests.rs b/crates/tinyinference-llm/src/providers/openai/mod_tests.rs
index 76fab26e..81d25f3a 100644
--- a/crates/tinyinference-llm/src/providers/openai/mod_tests.rs
+++ b/crates/tinyinference-llm/src/providers/openai/mod_tests.rs
@@ -2003,6 +2003,31 @@ fn merge_system_preserves_user_image_blocks() {
     }
 }
 
+#[test]
+fn folded_system_messages_keep_their_json_blocks_as_sent_unfolded() {
+    // A system message's JSON block is serialized on the pass-through path;
+    // hoisting or merging it into the user turn must not drop it, and its
+    // blocks join exactly as the pass-through path joins them.
+    use crate::message::SystemMessage;
+    let structured = Message::System(SystemMessage {
+        content: vec![
+            ContentBlock::Text("Context: ".to_string()),
+            ContentBlock::Json(serde_json::json!({"tenant": "acme"})),
+        ],
+        ..Default::default()
+    });
+    let sent_as_is = r#"Context: {"tenant":"acme"}"#;
+
+    let hoisted = single_system_message(&[
+        Message::user("hi"),
+        structured.clone(),
+    ]);
+    assert_eq!(hoisted[0].text(), sent_as_is);
+
+    let merged = merge_system_into_user(&[structured, Message::user("hi")]);
+    assert_eq!(merged[0].text(), format!("{sent_as_is}\n\nhi"));
+}
+
 #[test]
 fn merge_system_is_noop_without_system_messages() {
     let input = vec![Message::user("just user")];
diff --git a/crates/tinyinference-llm/src/providers/openai/transport.rs b/crates/tinyinference-llm/src/providers/openai/transport.rs
index e7fa8bfc..b17b4ebf 100644
--- a/crates/tinyinference-llm/src/providers/openai/transport.rs
+++ b/crates/tinyinference-llm/src/providers/openai/transport.rs
@@ -186,17 +186,20 @@ pub(super) fn auth_headers(auth: &AuthStyle, api_key: &str) -> Vec<(String, Stri
     }
 }
 
-/// Concatenates the text of a message's content blocks (non-text blocks — images,
-/// json, thinking — are ignored). Used to gather system-prompt text for merging.
+/// A system message's content as the pass-through path sends it
+/// (`translate_text_content`): text verbatim, JSON serialized, reasoning
+/// dropped, blocks joined with nothing between them. Folding with anything
+/// else would make a hoisted or merged prompt differ from the same prompt sent
+/// as-is, and would silently drop JSON blocks.
 fn content_text(content: &[ContentBlock]) -> String {
     content
         .iter()
         .filter_map(|block| match block {
-            ContentBlock::Text(text) => Some(text.as_str()),
+            ContentBlock::Text(text) => Some(text.clone()),
+            ContentBlock::Json(value) => Some(value.to_string()),
             _ => None,
         })
-        .collect::<Vec<_>>()
-        .join("\n")
+        .collect()
 }
 
 /// Folds all `system` messages into the first `user` message and drops the

From be71b6eb8107d01779e17b6af7a35c0cb0bdb9e8 Mon Sep 17 00:00:00 2001
From: M3gA-Mind <elvin@tinyhumans.ai>
Date: Fri, 23 Oct 2026 06:03:20 +0530
Subject: [PATCH 2/2] style: rustfmt the folding test

---
 crates/tinyinference-llm/src/providers/openai/mod_tests.rs | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/crates/tinyinference-llm/src/providers/openai/mod_tests.rs b/crates/tinyinference-llm/src/providers/openai/mod_tests.rs
index 81d25f3a..8f90e7a1 100644
--- a/crates/tinyinference-llm/src/providers/openai/mod_tests.rs
+++ b/crates/tinyinference-llm/src/providers/openai/mod_tests.rs
@@ -2018,10 +2018,7 @@ fn folded_system_messages_keep_their_json_blocks_as_sent_unfolded() {
     });
     let sent_as_is = r#"Context: {"tenant":"acme"}"#;
 
-    let hoisted = single_system_message(&[
-        Message::user("hi"),
-        structured.clone(),
-    ]);
+    let hoisted = single_system_message(&[Message::user("hi"), structured.clone()]);
     assert_eq!(hoisted[0].text(), sent_as_is);
 
     let merged = merge_system_into_user(&[structured, Message::user("hi")]);