@oisin-ee/pi-prewalk

Prewalk starts with the active planner model. After the planning nudge, validated local task activation opens the handoff gate. Without the task-provider capability, a successful todo call opens the gate instead. Imported workers need no bookkeeping call. The first subsequent edit or write result switches the session to the target model, even if that result failed. Nested calls through codemode also count. Without a callable todo tool, the gate is open.

Config

Put prewalk.json in the pi agent directory:

{
  "enabled": true,
  "target": { "model": "alias/luna", "thinking": "medium" }
}

A trusted project's .pi/prewalk.json replaces matching user keys. Prewalk reads both files again at each input. The target needs a provider-qualified model ID and configured credentials. Alias models need the alias extension.

Controls

Use /prewalk or /prewalk on to arm from the active model. Use /prewalk off to cancel without changing the model or config. Use /prewalk restart to select the saved default and arm again. Use /prewalk status to inspect branch state and config errors.

The startup flags are --prewalk, --no-prewalk, and --prewalk-into provider/model. Do not combine --no-prewalk with either arming flag. Flags affect only the startup session. New sessions use enabled from config. Resumed sessions do not arm automatically.

For a dogsled child, add "pi_args": ["--prewalk-into", "alias/luna"] to its profile. To suppress configured prewalk for that child, use "pi_args": ["--no-prewalk"].

State and context

The active branch stores arm, handoff, and off entries. The extension does not keep a separate in-memory protocol state. After a handoff, /new restores the planner unless a later model or thinking selection replaced the handoff target.

pi 1.3.0 permits persistent context edits only at actionable boundaries. Cancellation writes an off entry immediately. A context handler removes canceled planning steering before the next model request. The next turn or settlement boundary records the persistent removal.

Source

The protocol and prompts adapt oh-my-pi prewalk, including session/prewalk.ts and prompts/system/prewalk-{plan,continue,checklist}.md. The original project uses the MIT license. This package keeps the one-shot handoff semantics and adapts them to pi's branch entries.