geto-subagents

Fork-based, tmux-hosted subagents for pi: /review, /find, /plan, /chain, plus a generic subagent tool.

Key ideas

• Child session = fork of your conversation. Each subagent is a fresh interactive pi instance launched with pi --fork <your-session-file> --session-id <uuid>, so it inherits the entire conversation (no vague handoff of tasks/context) and appears as a child session of yours in /resume's tree.
• Results come back. The child reports its final output (atomic result.json on agent_settled) and shuts down; the parent returns the output to the caller. No need to watch or attach unless you want to.
• Attach anytime. pi --attach-subagent <id> attaches or switches to the child's tmux session from any terminal.
• View ladder (zellij is optional):
  1. inside zellij → subagent opens in a floating pane (stacked per subagent)
  2. inside tmux → opens as a new window (Ctrl+B n/p to flip)
  3. otherwise → the attach hint is printed; works everywhere Disable the zellij/tmux views with --no-zellij, GETO_SUBAGENTS_VIEW=attach, or just ignore the hint.

Install

pi install npm:geto-subagents
# or from this repo:
mkdir -p ~/.pi/agent/extensions/geto-subagents
ln -s "$PWD/packages/geto-subagents/index.ts" ~/.pi/agent/extensions/geto-subagents/index.ts
ln -s "$PWD/packages/geto-subagents/agents.ts" ~/.pi/agent/extensions/geto-subagents/agents.ts

Requires tmux (3.x) on PATH. Then /reload in pi.

Commands

| Command | Purpose | |---|---| | /review <prompt> [model] | Code review: findings table + verdict (APPROVE / APPROVE WITH NITS / REQUEST CHANGES) | | /find <prompt> [model] | Codebase navigation: geto-graph-first, exact file:line pointers | | /plan <prompt> [model] | Implementation planning: dependency-ordered file table, risks, phases | | /chain <step1> \| <step2> \| ... | Sequential subagent chain via an overlay dialog; each step forks the previous step's session; {chain_dir} is a shared scratch dir | | /subagents | List running geto-* tmux sessions |

Flags: --model <id>, --no-attach, --no-zellij. A trailing token that looks like a model (provider/id, :thinking) is consumed as the model.

Tool

subagent (AI-callable): { task, cwd?, provider?, model?, thinking? } — same machinery as the commands; calls are serialized (one child at a time).

How it works

1. The command/tool resolves model + trust, then writes the task (and role prompt for /review etc.) to a temp run dir under ~/.pi/agent/tmux-subagents/.
2. Child invocation (each arg shell-quoted):

   pi --fork <parent-session-file> --session-id <uuid> --name "geto <role> <short>"
      --provider <p> --model <m> --thinking <l> [--approve|--no-approve]
      [--append-system-prompt <role.md>] --extension <this-file> @task.md

3. tmux -S ~/.pi/agent/tmux-subagents.sock new-session -d (dedicated server), send-keys the command, remain-on-exit on.
4. The child runs in child mode (PI_TMUX_SUBAGENT_CHILD=1): on agent_settled it writes result.json (output, stopReason, session file, model) and shuts down. It also sets GETO_GOALS_DISABLED=1 so the geto-goals loop does not run inside subagents.
5. The parent polls result.json + capture-pane (live preview) until done, then returns the output (50KB/2000-line cap; full transcript in the child session file).

Releases

Versions, changelogs, tags, and npm publication are managed by Release Please from Conventional Commits. Do not edit the package version manually.

Notes

• pi --attach-subagent <id> validates the UUID, then switch-client (same tmux server) or attach-session (elsewhere, $TMUX stripped).
• Sessions are stored per-project in the default session dir, so /resume shows the child session linked to the parent.
• Role prompts live in agents.ts — edit and /reload to tweak behavior.