Four tools. No MCP. No sub-agents. It ships.

Code with only four tools: read, write, edit, bash. Author of the Pi coding agent; minimal-harness users.

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what to steal

Before adding a tool, ask if read, write, edit and bash already cover it.

Our takeaway from the source, not a quote.

Drawn from this card's sourced fields. Amber = older model named by the source. Rose = cut or replaced.

mario-zechner-pi-four-tools.toml

# Code with only four tools: read, write, edit, bash
# source: https://www.mariozechner.at/posts/2025-11-30-pi-coding-agent/

[rig]
who     = "Author of the Pi coding agent; minimal-harness users"
author  = "Mario Zechner"
date    = "2025-11-30"

harness = ["Pi"]
models  = ["Multi-provider (any supported model)"]

[keep]
  - Tools: read, write, edit, bash
[cut]
  - MCP
  - Sub-agents
  - Plan mode
  - Permission popups
  - To-dos

thing	status	why (per source)
MCP	removed	Not built in by design
Sub-agents	removed	Not built in
Plan mode	removed	Not built in
Permission popups	removed	Not built in
To-dos	removed	"they confuse models"

Source: https://www.mariozechner.at/posts/2025-11-30-pi-coding-agent/ · checked 2026-10-14

Let the agent write its own skills instead of installing MCPs

steal → Ask your agent to write a small skill for the job before reaching for an MCP.

Pi MCP

by Armin Ronacher

~/rigs/lws-pi-cold-start.tomlundated

Pi cold start: lazy-load the heaviest tools

steal → Make your heaviest tools opt-in so their schema is paid for only when used.

Pi Heavy tools at startup

by Kevin Lewis

~/rigs/nadimtuhin-mac-controls-pc-r….toml2026-09-01

Laptop as control room, home PC as the engine

steal → Run agents on an always-on box behind one model gateway; reach it with zero open ports.

Claude CodeCodexPi Any model behind 9Rout

by Nadim Tuhin