pi-rust
pi-rustThe pi agent in Rust.
Overview
pi-rust is the pi (opens in a new tab) coding agent by Mario Zechner, rebuilt in Rust. It’s fully compatible with pi and reads the same config files, so your setup works as is.
curl -fsSL https://ryanyannelli.com/file/pi-rust/install.sh | shcurl -fsSL https://ryanyannelli.com/file/pi-rust/install.sh | shirm https://ryanyannelli.com/file/pi-rust/install.ps1 | iexSource on GitHub (opens in a new tab)Releases (opens in a new tab)
- Memory per session
- ~35 MiB
- Less memory than Node pi
- 5×
- Runtime dependencies
- 0
- Platforms
- 7
Get the highlights.
One binary
Nothing to install but pi.
pi-rust is a single binary for Linux, macOS, and Windows. No Node, no runtime to set up.
Runs on any Linux
Linux builds are static, so they run on any distro and on Termux.
Verified downloads
The install script checks each archive against SHA256SUMS. No sudo, no telemetry.
Updates itself
pi update --self installs the latest release.
Memory
Run 20 agents at once.
20 pi-rust sessions running together used about a fifth of the memory of Node pi or Codex CLI.
Done sooner, too
All 20 pi-rust sessions finished first, ahead of Codex CLI and Node pi.
vs. Codex CLI
Codex CLI is also written in Rust, and it still peaked more than four times higher.
The test
Each tool ran the same 20 read-only sessions on one Mac. The method and raw samples are in the repo.
Interactive
The pi you know, in your terminal.
Run pi in a project to start. Type while the agent works to steer it, or press Alt+Enter to queue a follow-up.
Slash commands
Type / for commands like /model, /tree, /fork, and /compact.
Resume any session
pi -c picks up the last session, and pi -r lets you choose one.
Prompt history
Up and Down scroll through prompts from every project. Ctrl+R searches them.
Notifies when done
Long runs end with a terminal notification.
Only in pi-rust
Six commands upstream doesn’t have.
/context
Shows what fills the context window, part by part.
/review
Has the agent list bugs, risky changes, and missing tests by severity, without touching files.
/undo
Restores the files the agent changed in the last prompt.
/retry
Runs the last prompt again on a new branch, so the old answer stays.
/init
Has the agent explore the project and write an AGENTS.md.
/diff
Shows the git diff, with the stat and untracked files.
Scripting
Made for scripts, too.
pi -p runs once and prints the answer. --mode json and --mode rpc stream events instead.
Run limits
--max-turns and --max-cost stop a run, and pi -c picks it back up.
Structured output
With --output-schema, the answer is JSON that matches your schema. If it doesn’t, pi asks again.
Pipes and files
Pipe a log into pi, attach files with @notes.md, and read the answer from stdout.
Editors
pi, inside Zed.
pi --mode acp runs pi as an external agent in Zed and other Agent Client Protocol (ACP) editors.
In the editor
The editor shows tool call diffs, terminals, the model picker, and slash commands.
Pick up in the terminal
Editor sessions are regular pi sessions, so pi -r can resume them.
Log in from the editor
With no model set up, the editor offers to open pi in a terminal so you can log in.
Providers
Every provider. Only the models you can use.
pi-rust speaks every wire protocol upstream pi does, including Anthropic, OpenAI, Bedrock, and Vertex. With a key set, it lists only the models your account can use.
OAuth logins
/login signs in to Anthropic, OpenAI Codex, GitHub Copilot, OpenRouter, and more.
Keys stay on your host
Model list requests don’t follow redirects, so your key only goes to the host you set.
Local models
llama.cpp servers and virtual models work the same as upstream pi.
Extensions
Node modules, without Node.
Extensions run on embedded QuickJS, with TypeScript and every Node built-in module.
Packages
pi install npm:<package> adds extensions, skills, prompt templates, and themes.
MCP
pi has a Model Context Protocol (MCP) client with OAuth. Manage servers with /mcp.
Codemode
A sandboxed JavaScript runtime where the model writes scripts that call tools.
Unsupported APIs
An API that can’t work throws ERR_PI_UNSUPPORTED. Native npm addons don’t load.
Upstream parity
Everything pi does, and more.
pi-rust has every feature of upstream pi, and a daily check keeps it in sync.
Your config carries over
auth.json, settings.json, models.json, MCP servers, skills, and themes work in both.
Upstream bugs, fixed
pi-rust fixes bugs that are still open upstream, like strict tools on Bedrock and stuck pastes.
Older setups
On first run, pi-rust moves files from older pi layouts, like upstream pi does.
Libraries
Use only the parts you need.
Use the LLM API, the agent loop, or the terminal UI as Rust crates on their own, or embed pi through a C ABI.
pi-ai
Message types, streaming events, providers, OAuth, and the model registry.
pi-agent
The agent loop, tool argument validation, and the stateful Agent.
pi-embedded
Runs pi sessions inside a native app, with a C header.
pi-durable
Durable sessions in memory, SQLite, or JSONL.
Even more
All the little things.
pi doctor
Checks the install, PATH, config, and credentials. It never prints a secret.
Sessions and stats
pi sessions lists and prunes saved sessions. pi stats totals tokens and cost.
Markdown export
/export notes.md writes the session as Markdown.
Shell completion
Completion for Bash, zsh, fish, and PowerShell includes model names.
No rg or fd downloads
grep and find use the Rust ignore crate, so pi doesn’t download rg or fd.
Word jumps in CJK and Thai
Word movement in the editor works in Chinese, Japanese, Korean, and Thai.
Get started
One line to install.
On Linux and macOS, run the script. pi doctor checks the install, and pi starts a session. On Windows, run this in PowerShell:
irm https://ryanyannelli.com/file/pi-rust/install.ps1 | iexcurl -fsSL https://ryanyannelli.com/file/pi-rust/install.sh | shpi doctorpi