Pi Coding Agent

Axiom installs into Pi — the minimal, open-source terminal coding agent — with one native command that delivers its skills, its /axiom-* commands, and its hooks. Pi runs the same SKILL.md skills Axiom ships in Claude Code, so the expertise carries over with no conversion.

What You Get

Axiom's full skill catalog — 286 skills covering:

• SwiftUI – layout, navigation, animations, performance, architecture, debugging
• Data – SwiftData, Core Data, GRDB, CloudKit, migrations, Codable
• Concurrency – Swift 6, actors, Sendable, async/await, synchronization
• Performance – memory leaks, profiling, energy, Instruments workflows
• Networking – URLSession, Network.framework, connection diagnostics
• Build – Xcode debugging, code signing, build optimization, SPM
• Integration – StoreKit, widgets, push notifications, camera, contacts, haptics
• Apple Intelligence – Foundation Models, on-device AI, CoreML
• Accessibility – VoiceOver, Dynamic Type, WCAG compliance

Pi keeps only the router descriptions in context and loads each router's full instructions — and the 286 skills beneath them — on demand (progressive disclosure). That's the same two-layer routing Axiom is built around, so the catalog costs few tokens.

Prerequisites

You need Pi itself (pi.dev), plus git for pi install or Node.js 18+ for the npx skills alternative.

Installation

pi install (recommended)

pi install git:github.com/CharlesWiltgen/Axiom

Pi clones the repo, reads its pi manifest (pi.skills and pi.extensions), and loads Axiom's router skills plus the axiom-pi extension, which adds the /axiom-* commands and the hooks. There's no build step: Pi runs the extension's TypeScript directly.

For the current project only:

pi install git:github.com/CharlesWiltgen/Axiom -l

Verifying Installation

Run pi list to see the installed package. Inside Pi, type / — you'll see both the /skill:axiom-* skills and the /axiom-* commands.

npx skills (cross-agent alternative)

npx skills add CharlesWiltgen/Axiom -a pi -g

This installs the skills only, without the commands or hooks. skills.sh is a cross-agent installer that also targets Codex, Cursor, and Claude Code, so reach for it when you want one workflow across assistants, or just the skills. -a pi targets Pi; -g is global (omit it for a project-scoped .pi/skills/ you can commit). To add the commands and hooks on top, see Commands and Hooks.

Manual (clone and point Pi at the skills)

To run from a checkout, clone the repo and point Pi at the skills directory:

cd ~ && git clone https://github.com/CharlesWiltgen/Axiom.git

Pass it per-session with the repeatable --skill flag:

pi --skill ~/Axiom/.claude-plugin/plugins/axiom/skills

…or make it permanent in your Pi settings:

{
  "skills": ["~/Axiom/.claude-plugin/plugins/axiom/skills"]
}

Pi discovers every router SKILL.md file recursively from this one path. Run cd ~/Axiom && git pull to update.

Commands and Hooks

The recommended pi install already includes the axiom-pi extension. (The npx skills and manual paths are skills-only; if you used one, add the extension by symlinking the repo's axiom-pi/ into Pi's extensions directory — ln -s ~/Axiom/axiom-pi ~/.pi/agent/extensions/axiom-pi — or switch to pi install.)

It adds:

• Commands – /axiom-fix-build, /axiom-audit <area>, /axiom-health-check, /axiom-analyze-crash, /axiom-profile, /axiom-console, /axiom-ui, and 8 more. Each runs the matching skill in your current session.
• Session guardrail – Injects the same iOS and Xcode version facts Axiom gives Claude Code and Codex, naming the Xcode you've switched to (so your assistant never claims a newer iOS "doesn't exist"), and lists which Axiom tools are on your PATH. It runs only in Apple projects; override that with AXIOM_SESSION_CONTEXT=always or never (see Non-Apple Projects).
• Tool hooks – On Swift writes, flags @State without an access level and SwiftData to-many relationships without a default; routes crash-file reads to xcsym; and suggests skills based on command output. They also run only in Apple projects, with the same override.

Command-Line Helpers

Axiom's optional command-line helpers are axbuild (build and test diagnostics), xcproject (project inspection), xclog (console capture), xcsym (crash symbolication), xcui (simulator UI and accessibility), and xcprof (performance traces). They're prebuilt binaries for Apple Silicon Macs, and no Pi install method puts them on your PATH. Clone the repo (skip that line if you already have ~/Axiom) and symlink them:

cd ~ && git clone https://github.com/CharlesWiltgen/Axiom.git
ln -sf ~/Axiom/.claude-plugin/plugins/axiom/tools/* /usr/local/bin/

If /usr/local/bin doesn't exist yet, create it first with sudo mkdir -p /usr/local/bin. If ln reports a permission error, run it with sudo.

Once axbuild is on your PATH, Axiom's Pi extension lists it at session start and your assistant runs builds and tests through it, so the full log and report are saved. Without it, your assistant saves build output to a log file instead. See Tools.

With the binaries available, ask Pi to "capture the simulator console" or "symbolicate this crash" (the axiom-tools skill), or "build the app and show me the first error" (the axiom-build skill), and the skill drives the right helper.

Usage

Skills activate automatically based on your questions. Just ask:

"I'm getting BUILD FAILED in Xcode"
"How do I fix Swift 6 concurrency errors?"
"My app has memory leaks"
"I need to add a database column safely"

To force a specific skill, invoke it as a command — Pi registers every skill as /skill:<name>, and the extension adds the /axiom-* commands:

/skill:axiom-build
/axiom-fix-build
/axiom-audit memory

Updating

pi update          # if you used pi install
npx skills update  # if you used npx skills

For the manual method, run cd ~/Axiom && git pull.

If you linked the command-line helpers from the plugin's old bin/ folder, run the ln -sf line under Command-Line Helpers again after you pull. The helpers now live in tools/, so the old links no longer resolve.

Removing

pi remove git:github.com/CharlesWiltgen/Axiom   # if you used pi install
npx skills remove -a pi -g                       # if you used npx skills

Differences from Claude Code

Pi consumes Axiom's skills natively, and pi install adds the commands and hooks via the axiom-pi extension. The one thing it can't match is Claude Code's autonomous, parallel agents — Pi has no sub-agent system.

Feature	Claude Code	Pi
Skills	Full catalog	Full catalog — the routers load the 286 skills on demand
Agents	43 autonomous auditors	Not supported — Pi has no sub-agent system
Commands	17 /axiom:* commands	/axiom-* — included with pi install
Hooks	Session + tool hooks	Included with pi install
Built-in tools	Bundled; Axiom's session hook puts them on PATH	Run through Pi's shell once you add them to your PATH (see above)
Installation	/plugin marketplace add	pi install git:…/Axiom (or npx skills … -a pi for skills only)

The audits those agents run (memory leaks, concurrency, Core Data safety, and so on) still work as skills — ask Pi to "audit my code for memory leaks", or use /axiom-audit memory. They run one at a time in your session, rather than in parallel with their own context as Claude Code's agents do.

Troubleshooting

Skills or commands not appearing in Pi

• Run pi list (for pi install) or npx skills list -g (for npx skills) to verify what's installed.
• Confirm Pi is reading the location: global skills live in ~/.pi/agent/skills/ (or ~/.agents/skills/); project skills in .pi/skills/ (or .agents/skills/). Project resources load only after you trust the directory.
• If the /axiom-* commands are missing, you installed skills only — add the extension (see Commands and Hooks).

A skill's instructions never load

Pi loads full instructions on demand. If a match isn't triggering, name the skill explicitly with /skill:axiom-<name>.

Also Available

• Claude Code – Full Axiom experience with 43 autonomous agents and 17 commands
• Claude App – Skills in chat, plus agents and hooks in Cowork
• Codex Plugin – Native skills for the OpenAI Codex CLI, web app, and IDE extensions
• Cursor Plugin – Native skills, agents, commands, and hooks for Cursor on macOS
• MCP Server – Skills in VS Code, Cursor, Gemini CLI, and any MCP-compatible tool
• Xcode Integration – Axiom's skills inside Xcode's Claude Agent and Codex, through MCP