Pi 1.0 is out: the minimal harness is locked in as a stable platform, with MCP added via Codemode, virtual models, and a separate Pi Durable.
Pi finally released
https://earendil.com/posts/pi-1-0/
On October 1 Earendil shipped Pi 1.0: the move from 0.99 to 1.0 signals that the core is stable, MIT license. According to the team, Pi is used by hundreds of thousands of people every week. The release includes a new TUI theme and fullscreen by default.
Jev router. The demo shows Pi writing itself an extension with the router/auto virtual model — planning on Claude Opus and implementing on GPT-6 Luna, with the Jev classifier deciding when to switch. /session then breaks down cost by physical models and cache.
Virtual models are registered via pi.registerVirtualModel(), the footer shows the real routed model.
Why MCP was brought into core
https://earendil.com/posts/you-said-no-mcp/
pi.dev used to have a proud No MCP badge. Now MCP has been added, explained in a separate post You Said No MCP! Three reasons:
- MCP has changed for the better over the year and become more stateless
- a plain MCP extension lacked the metadata to decide whether a tool is visible to the model or only from code
- a sandbox interpreter was needed anyway for Jev and image models
Codemode — how MCP was enabled
https://pi.dev/docs/latest/codemode
Codemode is a QuickJS JS sandbox on the harness side, not where bash runs. Instead of a hundred one-by-one calls, the model writes a script, calls tools in parallel, and filters out noise before returning to context. It turns on automatically when MCP is configured, or via defaultTools: ["+codemode"]. Each MCP tool is mcp__server__tool, exposure is a choice: codemode by default, deferred via tool_search, direct, hidden.
Hacker News discussion
https://news.ycombinator.com/item?id=49906637
https://news.ycombinator.com/item?id=49926069
Both posts hit the HN front page with hundreds of comments. Discussion was split: some praise it — a small initial prompt leaves more context for the model itself, and Codemode is interesting. Others say it contradicts the idea of minimalism, counting an extra 450k lines of code and over a dozen direct dependencies. In response the developers explain: Pi's minimalism is not about code size, but about 4 base tools — read, write, edit, and shell — the rest is added via extensions.
A practical nuance also surfaced separately: a Figma employee confirmed that their MCP server only accepts clients from an approved list, and Pi is not on it, and in general because many blocked OpenClaw, Pi on which it is built suffers from that.
Pi Durable — a separate experiment for long-lived agents
https://earendil.com/posts/pi-durable/
To avoid bloating the core, longevity was moved into a separate package Pi Durable. The split: Pi coding agent is one person in one terminal, if the process dies — you look yourself and continue, while Durable is a harness for agents running anywhere, surviving crashes, accessible from different surfaces and to multiple users. Each step is a task with a checkpoint, exactly-once submit via requestId, conversation forks without copying, ownership tree, state documents next to the transcript, background compaction, live steering from any client.
#piagent #pi #mcp #codemode #virtualmodels #jev