Add new thread items and rewire event parsing to use them (#5418)

1. Adds AgentMessage,  Reasoning,  WebSearch items.
2. Switches the ResponseItem parsing to use new items and then also emit
3. Removes user-item kind and filters out "special" (environment) user
items when returning to clients.

codex-rs/protocol/src/items.rs

@@ -1,3 +1,9 @@
+use crate::protocol::AgentMessageEvent;
+use crate::protocol::AgentReasoningEvent;
+use crate::protocol::AgentReasoningRawContentEvent;
+use crate::protocol::EventMsg;
+use crate::protocol::UserMessageEvent;
+use crate::protocol::WebSearchEndEvent;
 use crate::user_input::UserInput;
 use schemars::JsonSchema;
 use serde::Deserialize;
@@ -7,6 +13,9 @@ use ts_rs::TS;
 #[derive(Debug, Clone, Deserialize, Serialize, TS, JsonSchema)]
 pub enum TurnItem {
     UserMessage(UserMessageItem),
+    AgentMessage(AgentMessageItem),
+    Reasoning(ReasoningItem),
+    WebSearch(WebSearchItem),
 }
 
 #[derive(Debug, Clone, Deserialize, Serialize, TS, JsonSchema)]
@@ -15,6 +24,31 @@ pub struct UserMessageItem {
     pub content: Vec<UserInput>,
 }
 
+#[derive(Debug, Clone, Deserialize, Serialize, TS, JsonSchema)]
+pub enum AgentMessageContent {
+    Text { text: String },
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize, TS, JsonSchema)]
+pub struct AgentMessageItem {
+    pub id: String,
+    pub content: Vec<AgentMessageContent>,
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize, TS, JsonSchema)]
+pub struct ReasoningItem {
+    pub id: String,
+    pub summary_text: Vec<String>,
+    #[serde(default)]
+    pub raw_content: Vec<String>,
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize, TS, JsonSchema)]
+pub struct WebSearchItem {
+    pub id: String,
+    pub query: String,
+}
+
 impl UserMessageItem {
     pub fn new(content: &[UserInput]) -> Self {
         Self {
@@ -22,12 +56,104 @@ impl UserMessageItem {
             content: content.to_vec(),
         }
     }
+
+    pub fn as_legacy_event(&self) -> EventMsg {
+        EventMsg::UserMessage(UserMessageEvent {
+            message: self.message(),
+            images: Some(self.image_urls()),
+        })
+    }
+
+    pub fn message(&self) -> String {
+        self.content
+            .iter()
+            .map(|c| match c {
+                UserInput::Text { text } => text.clone(),
+                _ => String::new(),
+            })
+            .collect::<Vec<String>>()
+            .join("")
+    }
+
+    pub fn image_urls(&self) -> Vec<String> {
+        self.content
+            .iter()
+            .filter_map(|c| match c {
+                UserInput::Image { image_url } => Some(image_url.clone()),
+                _ => None,
+            })
+            .collect()
+    }
+}
+
+impl AgentMessageItem {
+    pub fn new(content: &[AgentMessageContent]) -> Self {
+        Self {
+            id: uuid::Uuid::new_v4().to_string(),
+            content: content.to_vec(),
+        }
+    }
+
+    pub fn as_legacy_events(&self) -> Vec<EventMsg> {
+        self.content
+            .iter()
+            .map(|c| match c {
+                AgentMessageContent::Text { text } => EventMsg::AgentMessage(AgentMessageEvent {
+                    message: text.clone(),
+                }),
+            })
+            .collect()
+    }
+}
+
+impl ReasoningItem {
+    pub fn as_legacy_events(&self, show_raw_agent_reasoning: bool) -> Vec<EventMsg> {
+        let mut events = Vec::new();
+        for summary in &self.summary_text {
+            events.push(EventMsg::AgentReasoning(AgentReasoningEvent {
+                text: summary.clone(),
+            }));
+        }
+
+        if show_raw_agent_reasoning {
+            for entry in &self.raw_content {
+                events.push(EventMsg::AgentReasoningRawContent(
+                    AgentReasoningRawContentEvent {
+                        text: entry.clone(),
+                    },
+                ));
+            }
+        }
+
+        events
+    }
+}
+
+impl WebSearchItem {
+    pub fn as_legacy_event(&self) -> EventMsg {
+        EventMsg::WebSearchEnd(WebSearchEndEvent {
+            call_id: self.id.clone(),
+            query: self.query.clone(),
+        })
+    }
 }
 
 impl TurnItem {
     pub fn id(&self) -> String {
         match self {
             TurnItem::UserMessage(item) => item.id.clone(),
+            TurnItem::AgentMessage(item) => item.id.clone(),
+            TurnItem::Reasoning(item) => item.id.clone(),
+            TurnItem::WebSearch(item) => item.id.clone(),
+        }
+    }
+
+    pub fn as_legacy_events(&self, show_raw_agent_reasoning: bool) -> Vec<EventMsg> {
+        match self {
+            TurnItem::UserMessage(item) => vec![item.as_legacy_event()],
+            TurnItem::AgentMessage(item) => item.as_legacy_events(),
+            TurnItem::WebSearch(item) => vec![item.as_legacy_event()],
+            TurnItem::Reasoning(item) => item.as_legacy_events(show_raw_agent_reasoning),
         }
     }
 }

codex-rs/protocol/src/protocol.rs

@@ -770,69 +770,13 @@ pub struct AgentMessageEvent {
     pub message: String,
 }
 
-#[derive(Debug, Clone, Deserialize, Serialize, JsonSchema, TS)]
-#[serde(rename_all = "snake_case")]
-pub enum InputMessageKind {
-    /// Plain user text (default)
-    Plain,
-    /// XML-wrapped user instructions (<user_instructions>...)
-    UserInstructions,
-    /// XML-wrapped environment context (<environment_context>...)
-    EnvironmentContext,
-}
-
 #[derive(Debug, Clone, Deserialize, Serialize, JsonSchema, TS)]
 pub struct UserMessageEvent {
     pub message: String,
     #[serde(skip_serializing_if = "Option::is_none")]
-    pub kind: Option<InputMessageKind>,
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub images: Option<Vec<String>>,
 }
 
-impl<T, U> From<(T, U)> for InputMessageKind
-where
-    T: AsRef<str>,
-    U: AsRef<str>,
-{
-    fn from(value: (T, U)) -> Self {
-        let (_role, message) = value;
-        let message = message.as_ref();
-        let trimmed = message.trim();
-        if starts_with_ignore_ascii_case(trimmed, ENVIRONMENT_CONTEXT_OPEN_TAG)
-            && ends_with_ignore_ascii_case(trimmed, ENVIRONMENT_CONTEXT_CLOSE_TAG)
-        {
-            InputMessageKind::EnvironmentContext
-        } else if starts_with_ignore_ascii_case(trimmed, USER_INSTRUCTIONS_OPEN_TAG)
-            && ends_with_ignore_ascii_case(trimmed, USER_INSTRUCTIONS_CLOSE_TAG)
-        {
-            InputMessageKind::UserInstructions
-        } else {
-            InputMessageKind::Plain
-        }
-    }
-}
-
-fn starts_with_ignore_ascii_case(text: &str, prefix: &str) -> bool {
-    let text_bytes = text.as_bytes();
-    let prefix_bytes = prefix.as_bytes();
-    text_bytes.len() >= prefix_bytes.len()
-        && text_bytes
-            .iter()
-            .zip(prefix_bytes.iter())
-            .all(|(a, b)| a.eq_ignore_ascii_case(b))
-}
-
-fn ends_with_ignore_ascii_case(text: &str, suffix: &str) -> bool {
-    let text_bytes = text.as_bytes();
-    let suffix_bytes = suffix.as_bytes();
-    text_bytes.len() >= suffix_bytes.len()
-        && text_bytes[text_bytes.len() - suffix_bytes.len()..]
-            .iter()
-            .zip(suffix_bytes.iter())
-            .all(|(a, b)| a.eq_ignore_ascii_case(b))
-}
-
 #[derive(Debug, Clone, Deserialize, Serialize, JsonSchema, TS)]
 pub struct AgentMessageDeltaEvent {
     pub delta: String,