Pi Durable is a library for building agents whose state survives crashes and restarts. Paired with Cloudflare Durable Objects, it provides a foundation for shared cloud sessions. Its pluggable backends also support local deployments. Here are four things worth building with these primitives.
1. Durable agents for high-stakes workflows
Pi Durable can identify interrupted operations and avoid automatically replaying unsafe calls. Imagine an agent refunding a customer, then crashing before it gets confirmation. You don't want it refunding the customer twice.
Pi Durable checkpoints execution, recording the intent to execute a tool call and whether it completed. After a crash, it knows which operations were interrupted. Calls that aren't marked safe to replay aren't automatically repeated, so your app can check whether the refund went through before proceeding.
2. Shared team agents
Pi Durable and Cloudflare Durable Objects are a great foundation for multiplayer agentic coding.
Pi@pidotdevBuild with Pi Durable on Cloudflare, a walkthrough of how to create a multiplayer chat agent, including subagents, on Durable Objects.
A Durable Object holds the persistent agent state. Multiple clients can connect to the same session, incoming messages are queued or used to steer the agent, and updates are streamed to everyone.
Imagine an agent picking up a GitHub issue and working on a pull request while teammates watch or steer the same conversation from their phones, browsers, or terminals. Earendil's shared-chat tutorial demonstrates the shared-session foundation for this.
3. Agents that run anywhere
Mario Zechner, the creator of Pi, built a Pi Durable Android app that runs the agent harness and stores its state locally on his phone, while model calls happen remotely.
Pi Durable separates agent state from execution, with pluggable storage and execution backends. The harness can run anywhere there's a compatible JavaScript runtime, and its tools can execute on another machine.
Your durable agent doesn't need an always-running terminal or cloud server just to preserve its state. The harness can run locally, on a phone, or in the cloud.
Mario Zechner@badlogicgamesthis weekend, i'm finally replacing Claude for Android with a little pi durable thing that runs fully on my phone.4. Build new tools on top of agent state
This is the one we're most excited about.
Pi Durable persists structured tasks, checkpoints, and interrupted operations. That means you can inspect an agent's execution state without asking the model to reconstruct what happened.
We experimented with putting Pi Durable inside a Cloudflare Durable Object and visualizing its stored state without waking the agent.
Imagine using that data to build:
- Debugging dashboards showing which task or tool call was interrupted by a crash.
- Reliability metrics showing which tool calls repeatedly fail or need recovery.
- Multiplayer dashboards showing pending tasks, who steered an agent, and when.
Durable execution state becomes a new primitive you can build tools on top of, with uses beyond crash recovery.
Episode timestamps
- 00:00What is Pi Durable?
- 07:06Idea 1: Durability for high-stake workflows
- 13:16How to build with Pi Durable
- 16:31Durable storage: local vs. cloud
- 19:46Pi Durable + Cloudflare Durable Objects
- 32:20Idea 2: Multiplayer agents with shared state
- 35:01Idea 3: Running the harness on a phone
- 37:45Idea 4: Inspecting persistent agent state