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 — 254 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 27 router descriptions in context and loads each skill's full instructions — and the 254 skills beneath them — on demand (progressive disclosure). That's the same two-layer routing Axiom is built around, so the catalog stays cheap on tokens.

Prerequisites

You already have Pi (this is a Pi install guide — if not, grab it at pi.dev). The commands below also need git (for pi install) or Node.js 18+ (for the npx skills alternative).

Installation

pi install (recommended)

pi install git:github.com/CharlesWiltgen/Axiom

One command, everything. Pi clones the repo, reads its pi manifest (pi.skills + pi.extensions), and loads the 27 skills plus the axiom-pi extension — the /axiom-* commands and the hooks. There's no build step (Pi runs the extension's TypeScript directly) and no npm package to publish.

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 27 skills only — no commands or hooks. It's the same skills.sh installer Codex, Cursor, and Claude Code use, so reach for it when you want one cross-agent workflow 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 each of the 27 router SKILL.md files 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 triggers the matching skill inline.
• Session guardrail – injects the iOS/Xcode version ground truth (so the agent never claims iOS 26 "doesn't exist") and lists which Axiom tools are on your PATH. Gated to Apple projects; override with AXIOM_SESSION_CONTEXT=always|never.
• Tool hooks – runs swiftformat on Swift writes, flags @State without an access level, routes crash-file reads to xcsym, and surfaces skill hints from command output.

Built-in Tools (xclog, xcsym, xcui, xcprof)

Axiom ships four command-line tools — xclog (console capture), xcsym (crash symbolication), xcui (simulator UI/accessibility), and xcprof (performance traces). They're prebuilt binaries, and no install method puts them on your PATH automatically. Clone the repo and symlink them:

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

With the binaries available, ask Pi to "capture the simulator console" or "symbolicate this crash" and the axiom-tools skill (plus the extension's session hook) will drive them.

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.

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	27 routers — the full 254 skills, loaded on demand
Agents	40 autonomous auditors	Not supported — Pi has no sub-agent system
Commands	15 /axiom:* commands	/axiom-* — included with pi install
Hooks	Session + tool hooks	Included with pi install
Built-in tools	Bundled on the plugin's PATH	Run via Pi's shell once added 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 run as skills — ask Pi to "audit my code for memory leaks", or use /axiom-audit memory. What Pi can't replicate is the parallel, isolated-context fan-out Claude Code's agents provide.

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 40 autonomous agents and 15 commands
• Codex Plugin – Native skills for the OpenAI Codex CLI, web app, and IDE extensions
• MCP Server – Skills in VS Code, Cursor, Gemini CLI, and any MCP-compatible tool
• Xcode Integration – Direct Xcode MCP bridge for in-editor assistance