0.9.90

On Pi, a running agent's list_agents entry gains an activity field: its current tool call, or the last one once it ended, as the tool name and a one-line summary of its arguments, and the first line of its latest message. A footer line, pstack: 2 running · a1b2c3d4 bash: ls -la, names the count and the most recently active agent while any runs, including one send_message resumes after a reload, and clears when none does. The new /pstack-agents command shows each agent's status, activity, transcript path, and the command to read it: tail -f while it runs, pi --export once it ended. Activity is read from the child's RPC stream and held in memory. The extension never appends it to the session or sends it as a message, so the model sees it only in a list_agents result, and the child's session has no second writer. Only the top-level session sets the footer. @Nickonomic asked for a way to see a background agent's work while it runs (#279); this completes the live view that 0.9.89's transcript path began.