open_ai: Support reasoning content (#43662)

Aero and Bennet Bo Fenner created 2 days ago

Support for Kimi K2 Thinking

Release Notes:

- Added support for thinking traces when using OpenAI-API-compatible AI providers

---------

Co-authored-by: Bennet Bo Fenner <[e-mail]>

Change summary

crates/language_models/src/provider/open_ai.rs | 21 ++++++++++++++++++-
crates/open_ai/src/open_ai.rs                  |  2 +
2 files changed, 21 insertions(+), 2 deletions(-)

Detailed changes

crates/language_models/src/provider/open_ai.rs

@@ -426,7 +426,14 @@ pub fn into_open_ai(
         for content in message.content {
             match content {
                 MessageContent::Text(text) | MessageContent::Thinking { text, .. } => {
-                    if !text.trim().is_empty() {
+                    let should_add = if message.role == Role::User {
+                        // Including whitespace-only user messages can cause error with OpenAI compatible APIs
+                        // See https://github.com/zed-industries/zed/issues/40097
+                        !text.trim().is_empty()
+                    } else {
+                        !text.is_empty()
+                    };
+                    if should_add {
                         add_message_content_part(
                             open_ai::MessagePart::Text { text },
                             message.role,
@@ -792,8 +799,18 @@ impl OpenAiEventMapper {
         };
 
         if let Some(delta) = choice.delta.as_ref() {
+            if let Some(reasoning_content) = delta.reasoning_content.clone() {
+                if !reasoning_content.is_empty() {
+                    events.push(Ok(LanguageModelCompletionEvent::Thinking {
+                        text: reasoning_content,
+                        signature: None,
+                    }));
+                }
+            }
             if let Some(content) = delta.content.clone() {
-                events.push(Ok(LanguageModelCompletionEvent::Text(content)));
+                if !content.is_empty() {
+                    events.push(Ok(LanguageModelCompletionEvent::Text(content)));
+                }
             }
 
             if let Some(tool_calls) = delta.tool_calls.as_ref() {

crates/open_ai/src/open_ai.rs

@@ -463,6 +463,8 @@ pub struct ResponseMessageDelta {
     pub content: Option<String>,
     #[serde(default, skip_serializing_if = "is_none_or_empty")]
     pub tool_calls: Option<Vec<ToolCallChunk>>,
+    #[serde(default, skip_serializing_if = "is_none_or_empty")]
+    pub reasoning_content: Option<String>,
 }
 
 #[derive(Serialize, Deserialize, Debug, Eq, PartialEq)]