system-prompt-switch

Pick, stack, edit, and forget : system prompts that follow you from Pi to OMP without re-explaining yourself.

A Pi / OMP extension that manages custom system prompts per session: interactive modals, cumulative stacking, two scopes (local repo + global home), CRUD commands, and an above-editor banner that always shows what's active.

Contents: Why · Install · Screenshots · What it does · Commands · How prompts live · Environment variables · Developers

Why not just edit AGENTS.md?

Install

OMP

omp install npm:system-prompt-switch

PI

pi install npm:system-prompt-switch

That's it. The extension registers on next session start. Works in both Pi and OMP.

Quick start

1. Start Pi or OMP. The startup modal opens.
2. Run /sps-new, name a prompt, write it, Ctrl+Q to save.
3. Run /sps-select to switch prompts, or /sps-inject to stack several for the next message.

Screenshots

Startup session modal - pick a prompt or create one:

Editor banner while creating a new prompt (Ctrl+Q submit, Esc cancel):

Demo GIFs:

1. Select / Create system prompt when new session

2. Update system prompt (local or global)

3. Inject one or several system prompts for next message

4. Get information or logs

5. Delete a system prompt

What it does

• Per-session prompts - your active prompt is bound to the session ID, never leaks between concurrent or sequential sessions.
• Two scopes, one mental model - [local] lives in your repo (.agents/system-prompts-switch/, committable), [global] lives in your home (~/.pi or ~/.omp/agent/system-prompts-switch/). Same file can exist in both; local wins for the repo session.
• Stack multiple prompts - /sps-inject adds prompts cumulatively. [global] <system-prompt-name>.md + [local] project-rules.md is a valid active state.
• Above-editor banner - the active prompt is rendered directly above your input prompt so you never forget which one is loaded.
• Self-describing extension context - every resolved prompt includes a leading block that tells the LLM what this extension is, where prompt files live, and how to inspect/change them. The block is loaded from assets/templates/extension-context.md so you can tweak the wording without touching code.
• Per-project default - your last choice in a project (startup modal, /sps-select, or a prompt just created with /sps-new, including (None)) becomes that project's default. New sessions there apply it silently, with no startup modal. Pick another with /sps-select to change it. If the default's file is gone, it is forgotten and the modal shows again. Dismissing the modal does not set a default.
• Startup modal - on terminal launch, pick (None), an existing prompt, or create one. Enabled by default; set promptOnStartup to false to skip it while retaining /sps-select and other commands:
  • OMP: ~/.omp/agent/config.yml

    systemPromptSwitch:
      promptOnStartup: false

  • Pi: ~/.pi/agent/extensions/system-prompt-switch.json

    { "promptOnStartup": false }

• Merge modes - append (default, safe) keeps base instructions; replace uses your prompt as the base while preserving tools, skills, and project context.
• Live logging to ~/.pi/agent/logs/system-prompt-switch.log / ~/.omp/agent/logs/system-prompt-switch.log, with /sps-logs [lines] inside the session.

Commands

How prompts live

Legacy prompts in ~/.pi/agent/system-prompts/ are auto-migrated on first run.

Reading the active prompt from another app

sessions.json is a public contract for clients (for example a chat UI driving omp over ACP): one entry per session ID, fields are only ever added.

{
  "<sessionId>": {
    "activePrompts": [{ "name": "reviewer.md", "scope": "global-omp" }],
    "mode": "append",
    "enabled": true,
    "decided": true
  }
}

scope is local, global-omp or global-pi; mode is append or replace. To change it, send /sps-select <name> or /sps-mode append|replace as a prompt in that session.

Over ACP the startup modal does not block: the client may send the first message before the user picks, so that message runs without the prompt. A client that picks the prompt itself starts the host with SPS_START_PICKER=0: no startup modal, then it sends /sps-select <name> before the first message. Unset (the default, e.g. the terminal) keeps the modal.

Environment variables

All optional. Set them in the shell that launches Pi or OMP.

The startup modal can also be turned off with the promptOnStartup setting, see What it does.

Editor shortcut note

When /sps-new or /sps-edit opens the built-in editor, an above-editor banner shows the real shortcuts: Ctrl+Q to submit, Esc to cancel. The host's footer also advertises Ctrl+Enter submit and Ctrl+G external editor - these are not wired by this extension; ignore them.

For developers

Architecture, build, test, and contribution guide: see README.dev.md.

License

MIT