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pi-fabric

Programmable tool and agent runtime for Pi with one fabric_exec tool; includes an optional Jev loop for observe-decide-act.

ServicebetaMIT
View on GitHub ↗

Overview

pi-fabric is a programmable tool and agent runtime for the Pi coding agent. It gives Pi a single fabric_exec tool that runs checked TypeScript in isolated QuickJS (or sandboxed Python), composing core tools, MCP servers and captured extension tools, and calling host providers for one-shot workers, resident agents, event-driven actors, councils, workflows, mesh coordination and bounded recursion. Guardrails include approvals, isolation, timeouts, concurrency limits, recursion depth and shared cost budgets, with a native TUI dashboard. The README reports a Fabric-powered agent winning all 25 ARC-AGI-3 environments in one session.

Per the list summary, the runtime includes an optional Jev loop for observing state, making decisions and running bounded actions. The fetched README excerpt does not describe this loop, so its questions are inferred. It is MIT licensed and published on npm.

What the decision model decides

TypeQuestionAnswers
ChoiceWhich bounded action should the loop take given the observed state?(inferred)—

How it works

  1. Observe state inside a Fabric program.
  2. Ask Jev for a decision.
  3. Run the chosen bounded action.
  4. Repeat within budgets and guardrails.

Strengths

  • Bounded, budgeted decision loops inside a sandboxed runtime.
  • Composes tools, MCP and agents in code.

Caveats

  • Jev loop known only from the list summary.
  • Large runtime if you only need decisions.

Getting started

Install the pi-fabric npm package into Pi.

At a glance

Type
Service
Status
beta
Language
TypeScript
Runtime
Pi extension, QuickJS sandbox
Has code
yes
Has tests
yes
License
MIT

Use cases and integrations

How curated lists describe it

  • Pi’s programmable runtime includes an optional Jev loop for observing state, making decisions and running bounded actions.

    logicrw/awesome-jev-projects

Frequently asked questions

Where does Jev fit?

As an optional loop for observing state, deciding and running bounded actions, per the list summary.

What is fabric_exec?

A single tool that runs checked TypeScript or Python programs composing tools and agents.

Which agent does it extend?

Pi.

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