pi-claude-code

Pi extensions that shim Claude Code's tool API, letting agents, skills, and commands built for Claude Code run inside pi without modification.

Background

I had invested a lot of time building agents, skills, and workflow commands inside Claude Code. When I discovered pi and its advantages as an agent harness — better session management, branching, extensibility, multi-provider support — I wanted to switch. But I didn't want to throw away everything I had built.

The good news: the two systems are structurally very similar. Both have the concept of agents, skills, and commands. Skills are essentially a 1:1 mapping. The main friction point was the tool API — Claude Code exposes a specific set of named tools (Grep, Glob, TaskCreate, WebFetch, etc.) and my agents called those by name. Pi has equivalent capabilities but uses different tool names or different conventions.

Rather than rewriting all my agents to call pi's tools, I shimmed Claude Code's tool names as pi extensions. With those shims in place, every agent, skill, and command I had built continued to work unchanged — they still called Grep(...) and TaskCreate(...) and WebFetch(...), and pi now knew what to do with those calls.

The goal was not to replicate Claude Code inside pi. It was to make the tools that Claude Code agents expect to exist actually exist in pi, so the agents could run without modification. A thin compatibility layer, not a full reimplementation.

This package is the result of that work, extracted and generalized so others can do the same thing.

What's included

Tool	Extension	Description
Grep	Grep.ts	Pattern search in files → ripgrep / grep fallback
Glob	Glob.ts	Find files by glob pattern → rg --files / find fallback
LS	LS.ts	List directory contents → ls -la
AskUserQuestion	AskUserQuestion.ts	Interactive choice picker with free-text fallback
todo	Task.ts	pi-native task list (add / toggle / list / clear)
TodoWrite	Task.ts	Replace entire task list (CC non-interactive mode)
TodoRead	Task.ts	Read task list in CC JSON format
TaskCreate	Task.ts	Create a task, returns { taskId }
TaskUpdate	Task.ts	Update task status / subject by taskId
TaskList	Task.ts	List all tasks as Array<{ id, subject, status, metadata }>
TaskGet	Task.ts	Get full details for one task
TaskStop	Task.ts	Stop/cancel a task
WebFetch	WebFetch.ts	Fetch URL as clean markdown (Jina Reader, no API key needed)
WebSearch	WebSearch.ts	Web search via Brave Search API (requires BRAVE_API_KEY)
Skill	Skill.ts	Execute a pi skill by name — loads SKILL.md, returns content
EnterPlanMode	PlanMode.ts	Enter read-only analysis mode
ExitPlanMode	PlanMode.ts	Present plan for user approval, restore full tools
Agent	Agent.ts	Delegate to a pi agent by name (requires pi-subagents)

Slash commands: /todos, /tasks (task list viewer) · /plan (toggle plan mode)
Keyboard: Ctrl+Alt+P toggles plan mode

Install

# Global install — available in all projects
pi install npm:@fractary/pi-claude-code

# Project-only install
pi install -l npm:@fractary/pi-claude-code

Or pin to a specific version:

pi install npm:@fractary/pi-claude-code@1.0.0

Optional dependencies

WebSearch requires a Brave Search API key (free tier):

export BRAVE_API_KEY="your-key-here"   # add to ~/.profile or ~/.zprofile

Agent requires pi-subagents:

pi install npm:pi-subagents

Both tools load and register cleanly without their dependencies — they only return a setup message when actually invoked.

Selective loading

Each extension is a separate file, so you can load only what you need using pi's package filtering:

{
  "packages": [{
    "source": "npm:@fractary/pi-claude-code",
    "extensions": ["!extensions/Agent.ts"]
  }]
}

Common patterns:

Goal	Filter
Everything except Agent shim	["!extensions/Agent.ts"]
Task management only	["extensions/Task.ts"]
Filesystem tools only	["extensions/Grep.ts", "extensions/Glob.ts", "extensions/LS.ts"]
Plan mode only	["extensions/PlanMode.ts"]

Documentation

• Converting Claude Code plugins to pi packages — how to add a pi section to package.json to map skills, commands, extensions, and agents (pi.agents is handled automatically by Agent.ts); covers single plugins and monorepos
• Migrating from Claude Code — how to structure agents, skills, and commands so they work in both harnesses; naming conventions and the namespace problem
• Filesystem tools — Grep, Glob, LS vs pi's built-in grep / find / ls; differences and tips
• Task management — TodoWrite vs TaskCreate; how shared state works; the /todos and /tasks commands
• Web tools — WebFetch via Jina Reader; WebSearch via Brave API; setup and differences from Claude Code
• Plan mode — EnterPlanMode / ExitPlanMode tools; /plan command; differences from Claude Code's plan mode

Contributing

When adding a new Claude Code tool shim:

1. Create extensions/ToolName.ts — file name must match the Claude Code tool name exactly
2. Match the parameter schema from the Claude Code tools reference
3. Store a full state snapshot in details{} for stateful tools (see Task.ts for the pattern)
4. Add the file to pi.extensions in package.json
5. Add a row to the tools table in this README
6. Bump the minor version and add a CHANGELOG entry

Staying in sync: Each extension file has a Derived from: and On Claude Code update: header comment pointing to the relevant schema source. When Claude Code updates a tool signature, update the corresponding extension and bump the version.

License

MIT