feat: add nick name to sub-agents (#12320)

Adding random nick name to sub-agents. Used for UX

At the same time, also storing and wiring the role of the sub-agent

codex-rs/app-server/src/codex_message_processor.rs

@@ -6658,6 +6658,8 @@ async fn read_summary_from_state_db_context_by_thread_id(
         metadata.cwd,
         metadata.cli_version,
         metadata.source,
+        metadata.agent_nickname,
+        metadata.agent_role,
         metadata.git_sha,
         metadata.git_branch,
         metadata.git_origin_url,
@@ -6678,9 +6680,12 @@ async fn summary_from_thread_list_item(
             .unwrap_or_else(|| fallback_provider.to_string());
         let cwd = it.cwd?;
         let cli_version = it.cli_version.unwrap_or_default();
-        let source = it
-            .source
-            .unwrap_or(codex_protocol::protocol::SessionSource::Unknown);
+        let source = with_thread_spawn_agent_metadata(
+            it.source
+                .unwrap_or(codex_protocol::protocol::SessionSource::Unknown),
+            it.agent_nickname.clone(),
+            it.agent_role.clone(),
+        );
         return Some(ConversationSummary {
             conversation_id: thread_id,
             path: it.path,
@@ -6735,13 +6740,17 @@ fn summary_from_state_db_metadata(
     cwd: PathBuf,
     cli_version: String,
     source: String,
+    agent_nickname: Option<String>,
+    agent_role: Option<String>,
     git_sha: Option<String>,
     git_branch: Option<String>,
     git_origin_url: Option<String>,
 ) -> ConversationSummary {
     let preview = first_user_message.unwrap_or_default();
-    let source = serde_json::from_value(serde_json::Value::String(source))
+    let source = serde_json::from_str(&source)
+        .or_else(|_| serde_json::from_value(serde_json::Value::String(source.clone())))
         .unwrap_or(codex_protocol::protocol::SessionSource::Unknown);
+    let source = with_thread_spawn_agent_metadata(source, agent_nickname, agent_role);
     let git_info = if git_sha.is_none() && git_branch.is_none() && git_origin_url.is_none() {
         None
     } else {
@@ -6901,6 +6910,35 @@ fn map_git_info(git_info: &CoreGitInfo) -> ConversationGitInfo {
     }
 }
 
+fn with_thread_spawn_agent_metadata(
+    source: codex_protocol::protocol::SessionSource,
+    agent_nickname: Option<String>,
+    agent_role: Option<String>,
+) -> codex_protocol::protocol::SessionSource {
+    if agent_nickname.is_none() && agent_role.is_none() {
+        return source;
+    }
+
+    match source {
+        codex_protocol::protocol::SessionSource::SubAgent(
+            codex_protocol::protocol::SubAgentSource::ThreadSpawn {
+                parent_thread_id,
+                depth,
+                agent_nickname: existing_agent_nickname,
+                agent_role: existing_agent_role,
+            },
+        ) => codex_protocol::protocol::SessionSource::SubAgent(
+            codex_protocol::protocol::SubAgentSource::ThreadSpawn {
+                parent_thread_id,
+                depth,
+                agent_nickname: agent_nickname.or(existing_agent_nickname),
+                agent_role: agent_role.or(existing_agent_role),
+            },
+        ),
+        _ => source,
+    }
+}
+
 fn parse_datetime(timestamp: Option<&str>) -> Option<DateTime<Utc>> {
     timestamp.and_then(|ts| {
         chrono::DateTime::parse_from_rfc3339(ts)
@@ -6937,6 +6975,8 @@ fn build_thread_from_snapshot(
         path,
         cwd: config_snapshot.cwd.clone(),
         cli_version: env!("CARGO_PKG_VERSION").to_string(),
+        agent_nickname: config_snapshot.session_source.get_nickname(),
+        agent_role: config_snapshot.session_source.get_agent_role(),
         source: config_snapshot.session_source.clone().into(),
         git_info: None,
         turns: Vec::new(),
@@ -6975,6 +7015,8 @@ pub(crate) fn summary_to_thread(summary: ConversationSummary) -> Thread {
         path: Some(path),
         cwd,
         cli_version,
+        agent_nickname: source.get_nickname(),
+        agent_role: source.get_agent_role(),
         source: source.into(),
         git_info,
         turns: Vec::new(),
@@ -6986,6 +7028,7 @@ mod tests {
     use super::*;
     use anyhow::Result;
     use codex_protocol::protocol::SessionSource;
+    use codex_protocol::protocol::SubAgentSource;
     use pretty_assertions::assert_eq;
     use serde_json::json;
     use std::path::PathBuf;
@@ -7131,6 +7174,41 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn summary_from_state_db_metadata_preserves_agent_nickname() -> Result<()> {
+        let conversation_id = ThreadId::from_string("bfd12a78-5900-467b-9bc5-d3d35df08191")?;
+        let source =
+            serde_json::to_string(&SessionSource::SubAgent(SubAgentSource::ThreadSpawn {
+                parent_thread_id: ThreadId::from_string("ad7f0408-99b8-4f6e-a46f-bd0eec433370")?,
+                depth: 1,
+                agent_nickname: None,
+                agent_role: None,
+            }))?;
+
+        let summary = summary_from_state_db_metadata(
+            conversation_id,
+            PathBuf::from("/tmp/rollout.jsonl"),
+            Some("hi".to_string()),
+            "2025-09-05T16:53:11Z".to_string(),
+            "2025-09-05T16:53:12Z".to_string(),
+            "test-provider".to_string(),
+            PathBuf::from("/"),
+            "0.0.0".to_string(),
+            source,
+            Some("atlas".to_string()),
+            Some("explorer".to_string()),
+            None,
+            None,
+            None,
+        );
+
+        let thread = summary_to_thread(summary);
+
+        assert_eq!(thread.agent_nickname, Some("atlas".to_string()));
+        assert_eq!(thread.agent_role, Some("explorer".to_string()));
+        Ok(())
+    }
+
     #[tokio::test]
     async fn removing_one_listener_does_not_cancel_other_subscriptions_for_same_thread()
     -> Result<()> {