preserve signature origins across compactions

1 files changed, 13 insertions, 5 deletions

diff --git a/libpanto/src/turn_persist.zig b/libpanto/src/turn_persist.zig
index 0147fbd..1dacfec 100644
--- a/libpanto/src/turn_persist.zig
+++ b/libpanto/src/turn_persist.zig
@@ -41,7 +41,7 @@ const Session = session_store.Session;
 pub fn persistTurn(
     alloc: Allocator,
     session: *Session,
-    conv: *const conversation.Conversation,
+    conv: *conversation.Conversation,
     start_index: usize,
     identity: WireIdentity,
     tools: []const ToolDecl,
@@ -52,14 +52,22 @@ pub fn persistTurn(
     const all_messages = conv.messages.items;
     var i = start_index;
     while (i < all_messages.len) : (i += 1) {
-        const msg = all_messages[i];
+        const msg = &all_messages[i];
         if (msg.role == .assistant and hasToolUseWithoutFollowingResults(conv, i)) {
             continue;
         }
+        // Stamp the producing identity once, on first persist. A message that
+        // already carries one (e.g. a kept-verbatim turn carried through
+        // compaction, or one rebuilt from disk) keeps it — only the messages
+        // freshly produced under `identity` are stamped now. This is what
+        // makes the stamp survive a later compaction onto a different model.
+        if (msg.identity == null) {
+            msg.identity = try conversation.dupeWireIdentity(alloc, identity);
+        }
         try batch.append(alloc, .{
-            .message = msg,
+            .message = msg.*,
             .usage = msg.usage,
-            .identity = identity,
+            .identity = msg.identity.?,
             .conversation = all_messages,
             .tools_available = tools,
         });
@@ -75,7 +83,7 @@ pub fn persistTurn(
 pub fn persistCompaction(
     alloc: Allocator,
     session: *Session,
-    conv: *const conversation.Conversation,
+    conv: *conversation.Conversation,
     identity: WireIdentity,
     tools: []const ToolDecl,
 ) !void {