Fix encoding of channel, recipient, and constrain

src/encoding.rs

@@ -838,17 +838,30 @@ impl Render<Message> for HarmonyEncoding {
             }
         };
 
-        // next render the header recipient, if there is one
-        if let Some(recipient) = &message.recipient {
-            if recipient != "all" {
-                self.render_text_into(format!(" to={recipient}"), into)?;
+        // Header channel vs recipient order: commentary uses <|channel|>… before to=…;
+        // other channels keep to=… before <|channel|>… (legacy order).
+        let commentary_channel_first = message.channel.as_deref() == Some("commentary");
+
+        if commentary_channel_first {
+            if let Some(channel) = &message.channel {
+                self.render_formatting_token_into(FormattingToken::Channel, into)?;
+                self.render_text_into(channel, into)?;
+            }
+            if let Some(recipient) = &message.recipient {
+                if recipient != "all" {
+                    self.render_text_into(format!(" to={recipient}"), into)?;
+                }
+            }
+        } else {
+            if let Some(recipient) = &message.recipient {
+                if recipient != "all" {
+                    self.render_text_into(format!(" to={recipient}"), into)?;
+                }
+            }
+            if let Some(channel) = &message.channel {
+                self.render_formatting_token_into(FormattingToken::Channel, into)?;
+                self.render_text_into(channel, into)?;
             }
-        }
-
-        // next header channel
-        if let Some(channel) = &message.channel {
-            self.render_formatting_token_into(FormattingToken::Channel, into)?;
-            self.render_text_into(channel, into)?;
         }
 
         // finally content type
@@ -865,7 +878,9 @@ impl Render<Message> for HarmonyEncoding {
                         self.render_text_into(rest, into)?;
                     }
                 } else {
-                    self.render_text_into(format!(" {content_type}"), into)?;
+                    self.render_text_into(" ", into)?;
+                    self.render_formatting_token_into(FormattingToken::ConstrainedFormat, into)?;
+                    self.render_text_into(content_type, into)?;
                 }
             } else {
                 self.render_text_into(format!(" {content_type}"), into)?;

test-data/test_does_not_drop_if_ongoing_analysis.txt

@@ -1 +1 @@
-<|start|>user<|message|>What is the weather in SF?<|end|><|start|>assistant<|channel|>analysis<|message|>User asks: “What is the weather in SF?” We need to use lookup_weather tool.<|end|><|start|>assistant to=functions.lookup_weather<|channel|>commentary <|constrain|>json<|message|>{"location": "San Francisco"}<|call|><|start|>functions.lookup_weather<|message|>{"temperature": 20, "description": "sunny"}<|end|><|start|>assistant
+<|start|>user<|message|>What is the weather in SF?<|end|><|start|>assistant<|channel|>analysis<|message|>User asks: “What is the weather in SF?” We need to use lookup_weather tool.<|end|><|start|>assistant<|channel|>commentary to=functions.lookup_weather <|constrain|>json<|message|>{"location": "San Francisco"}<|call|><|start|>functions.lookup_weather<|message|>{"temperature": 20, "description": "sunny"}<|end|><|start|>assistant

test-data/test_tool_response_parsing.txt

@@ -1 +1 @@
-<|start|>browser.search to=assistant<|channel|>commentary<|message|>{"result": "https://openai.com/"} 
+<|start|>browser.search<|channel|>commentary to=assistant<|message|>{"result": "https://openai.com/"} 

tests/test_harmony.py

@@ -245,7 +245,7 @@ def test_tool_call_with_constrain_tokenized_correctly(encoding_name):
     """
     encoding = load_harmony_encoding(encoding_name)
     text = (
-        "<|start|>assistant to=functions.get_weather<|channel|>commentary"
+        "<|start|>assistant<|channel|>commentary to=functions.get_weather"
         ' <|constrain|>json<|message|>{"location": "Tokyo"}<|call|>'
     )
     tokens = encoding.encode(text, allowed_special="all")