teardown · Mario Zechner
Four tools. No MCP. No sub-agents. It ships.
The author of Pi built a harness around four tools and deliberately left out what most agents ship by default.
01
The setup
Pi gives the model four tools: read, write, edit and bash. It works with many model providers.
02
What it leaves out
MCP, sub-agents, plan mode, permission popups and to-dos are all left out by design. On to-dos, Mario Zechner says "they confuse models".
03
Our read
Everything here is a subtraction. Each removed feature is something the model can rebuild with bash and files when it needs it, so the system prompt stays small and model-agnostic.
04
What to steal
Before adding a tool, check whether read, write, edit and bash already cover the job.
05
Where it shows up
Several other cards in our set build on Pi or its ideas, including metaist's switch from Claude Code and Kevin Lewis's lazy-loading of heavy Pi tools.
Facts from https://www.mariozechner.at/posts/2025-11-30-pi-coding-agent/ (2025-11-30). "Our read" is Agent Setups' analysis, not the author's words.
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103 capabilities installed, 90 never fired in 30 days