feat(cli): --name <title> for custom session display titles (#99)

src/cli/args.rs

@@ -72,6 +72,13 @@ pub(crate) struct Args {
     #[arg(long = "models", global = true, value_delimiter = ',')]
     pub(crate) scoped_models: Vec<String>,
 
+    /// Set the human-readable title (display name) of the new session. Visible
+    /// in `jcode --resume` and the session picker. Equivalent to setting
+    /// `JCODE_SESSION_NAME`. Existing sessions are unaffected — use
+    /// `jcode session rename <id> <name>` for those.
+    #[arg(long = "name", alias = "session-name", global = true)]
+    pub(crate) session_name: Option<String>,
+
     /// Log tool inputs/outputs and token usage to stderr
     #[arg(long, global = true)]
     pub(crate) trace: bool,

src/cli/startup.rs

@@ -97,6 +97,15 @@ fn parse_and_prepare_args() -> Result<Args> {
         }
     }
 
+    // --name <title>: translate to env so the next freshly-created top-level
+    // session picks it up as `Session::title`. Issue #99.
+    if let Some(ref text) = args.session_name {
+        let trimmed = text.trim();
+        if !trimmed.is_empty() {
+            crate::env::set_var("JCODE_SESSION_NAME", trimmed);
+        }
+    }
+
     if let Some(ref socket) = args.socket {
         server::set_socket_path(socket);
     }

src/session.rs

@@ -706,6 +706,20 @@ impl Session {
     }
 
     pub fn create(parent_id: Option<String>, title: Option<String>) -> Self {
+        // Issue #99: top-level user sessions can be auto-titled via
+        // `jcode --name <title>` (translated to `JCODE_SESSION_NAME`). Only
+        // apply when the caller didn't pass an explicit title and there is
+        // no parent (subagents/spawned children should not inherit the env).
+        let title = title.or_else(|| {
+            if parent_id.is_none() {
+                std::env::var("JCODE_SESSION_NAME")
+                    .ok()
+                    .map(|s| s.trim().to_string())
+                    .filter(|s| !s.is_empty())
+            } else {
+                None
+            }
+        });
         let now = Utc::now();
         let (id, short_name) = new_memorable_session_id();
         let is_debug = default_is_test_session();

src/session_tests/cases.rs

@@ -1223,3 +1223,27 @@ fn test_render_messages_and_images_share_tool_resolution_and_labels() {
         }
     );
 }
+
+#[test]
+fn jcode_session_name_env_titles_top_level_session() {
+    // Issue #99: `jcode --name "my-session"` is wired through the
+    // JCODE_SESSION_NAME env var so a freshly-created top-level session picks
+    // it up as Session::title. Subagents (parent_id=Some) must not inherit it
+    // so spawn children stay random-named for clarity.
+    let _lock = crate::storage::lock_test_env();
+    let _name = EnvVarGuard::set("JCODE_SESSION_NAME", "my custom title");
+
+    let top = Session::create(None, None);
+    assert_eq!(top.title.as_deref(), Some("my custom title"));
+
+    let spawned = Session::create(Some("parent_x".to_string()), None);
+    assert!(
+        spawned.title.is_none(),
+        "child sessions must not inherit JCODE_SESSION_NAME, got {:?}",
+        spawned.title
+    );
+
+    // Explicit title still wins over the env.
+    let explicit = Session::create(None, Some("explicit".to_string()));
+    assert_eq!(explicit.title.as_deref(), Some("explicit"));
+}