feat(feature): add terminal title renaming with session status

src/features/terminal/index.ts

@@ -0,0 +1 @@
+export * from "./title"

src/features/terminal/title.ts

@@ -0,0 +1,62 @@
+export type SessionStatus = "ready" | "processing" | "tool" | "error" | "idle"
+
+const STATUS_ICONS: Record<SessionStatus, string> = {
+  ready: "",
+  processing: "◐",
+  tool: "⚡",
+  error: "✖",
+  idle: "○",
+}
+
+export interface TitleContext {
+  sessionId: string
+  sessionTitle?: string
+  directory?: string
+  status?: SessionStatus
+  currentTool?: string
+  customSuffix?: string
+}
+
+const DEFAULT_TITLE = "OpenCode"
+const MAX_TITLE_LENGTH = 30
+
+function truncate(str: string, maxLen: number): string {
+  if (str.length <= maxLen) return str
+  return str.slice(0, maxLen - 1) + "…"
+}
+
+export function formatTerminalTitle(ctx: TitleContext): string {
+   const title = ctx.sessionTitle || DEFAULT_TITLE
+   const truncatedTitle = truncate(title, MAX_TITLE_LENGTH)
+
+   const parts: string[] = ["[OpenCode]", truncatedTitle]
+
+   if (ctx.status) {
+     parts.push(STATUS_ICONS[ctx.status])
+   }
+
+   return parts.join(" ")
+}
+
+function isTmuxEnvironment(): boolean {
+  return !!process.env.TMUX || process.env.TERM_PROGRAM === "tmux"
+}
+
+export function setTerminalTitle(title: string): void {
+  // Use stderr to avoid race conditions with stdout buffer
+  // ANSI escape sequences work on stderr as well
+  process.stderr.write(`\x1b]0;${title}\x07`)
+
+  if (isTmuxEnvironment()) {
+    process.stderr.write(`\x1bk${title}\x1b\\`)
+  }
+}
+
+export function updateTerminalTitle(ctx: TitleContext): void {
+  const title = formatTerminalTitle(ctx)
+  setTerminalTitle(title)
+}
+
+export function resetTerminalTitle(): void {
+  setTerminalTitle(`[OpenCode] ${DEFAULT_TITLE}`)
+}