Pi

Pi is built into Solipsist. There’s nothing to install: the agents run inside the Solipsist process, using Pi as a library.

What it needs

A model it can call. Any one of these:

• an OpenRouter key in SOLIPSIST_OPENROUTER_KEY (or pi.openrouter_key),
• a login saved in Pi: run pi, then /login,
• a provider in Pi’s own models.json, such as a model on your computer.

Until one of those exists, the status bar says Connect a model, and asking for something opens a dialog that says how, instead of starting a run that would fail.

It is your Pi

Solipsist reads Pi’s configuration the way the pi command does in the folder you run it from: ~/.pi/agent, and a project .pi in the folder. Your saved logins, skills and settings work here too. Pi’s session files for a run are kept where pi keeps them for that folder, so you can open one in pi afterwards.

Tools

An agent may use the tools in pi.tools (SOLIPSIST_PI_TOOLS, comma-separated). The default is read, grep, find, ls, bash, write and edit. It leaves out MCP, codemode and tool search, so an agent never starts your MCP servers.

• write and edit can only write to the page’s images folder. The page itself is never written by an agent: it answers with a suggestion, and you decide.
• bash runs where Solipsist runs and isn’t sandboxed. Remove it from pi.tools if you don’t want an agent to run commands.

A permission prompt from a Pi extension can’t be answered, because nobody is at the keyboard. It is refused and shows in the agent panel as an error.

Models

The picker shows a shortlist (pi.models, with your agent.preferred_models pinned to the top) and can search every model your Pi can run. Solipsist reads Pi’s model list from its files and doesn’t ask the network, so the list is as fresh as the last time you ran pi. To refresh it, run pi once.

A model is <provider>/<model>, for example openrouter/anthropic/claude-haiku-5.5. On a page it’s saved as pi:<provider>/<model>.

In the file

The settings are in Configuration: pi.models, pi.tools and pi.openrouter_key.