Agents
Phantom is built around running several coding agents at once. It knows six of them, and treats an agent session as something a tab has, not something you have to remember.
Supported agents
Section titled “Supported agents”Claude Code, Codex, OpenCode, Antigravity, Kimi Code and Pi.
Each one has a mark of its own in the sidebar, an entry in the new terminal menu, and an installer for its configuration format — JSON for most, TOML for Codex.
Starting a session
Section titled “Starting a session”From a group header or the new-terminal menu, pick an agent. Phantom opens a tab in the right working directory with the agent already running. A project group starts it at the project root; a worktree starts it in that checkout.
The state on the tab
Section titled “The state on the tab”A row shows whether its session is working, waiting on you, or done. That is the whole reason the sidebar exists: a dozen agents across a dozen repositories are otherwise a dozen identical tabs.
The state comes from hooks the agent runs. Install them from Settings › Agents with one click — Phantom writes a script into the agent’s own hooks directory and registers it. The script’s name carries the build’s name, so a development build cannot overwrite the one your installed copy uses.
For Claude Code the tab also shows the current plan, when there is one.
Resume
Section titled “Resume”Closing a tab kills the processes inside it, agent included. Reopening the tab —
by restoring the session or from the tab’s own menu — starts the agent again
with --resume against the conversation it had, so the session continues rather
than restarting.
Turn this off with Restore agent sessions in Settings.
Letting an agent drive Phantom
Section titled “Letting an agent drive Phantom”An agent can also act on the window it is running in: open a file at a line, read another terminal’s output, create a worktree. That is the MCP server, and it is documented in The MCP server.