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

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DeepSeek Harness as a desktop app for macOS and Windows.

Desktop DeepSeek Harness
https://www.deepseek.com/en/harness/
Now in public preview worldwide and open source under MIT, on the Cordis "everything is a plugin" architecture. Desktop so far only macOS Apple silicon and Windows 64-bit, essentially an Electron shell around the full dsh Web. Works with lots of providers including local ones: Settings → Models, a huge dropdown plus a custom model API tab with base URL, protocol, and key.

Installs in literally a few clicks: download the dmg/exe, log in, settings and workspaces carry over, nothing is lost. During setup there is a profile choice — office tasks or code — and an answer detail level. Out of the box it covers everyday routine, code, research with citations, scheduled background tasks, and in-session previews of results.

Trajectory tab
The site highlights Developer tools separately: a full execution trace in real time — system prompt, turns, tool calls, payloads, schemas, timings. People call this the main edge over other harnesses: transcript as the product backbone, append-only context design without cache bugs, two-way communication with subagents.

Agent presets
In Settings → Agent you can pick PTC / Minimal / Creator mode besides Standard. PTC mode includes everything from Standard, but tools are exposed via the Code Mode MCP/SDK so the model packs batches of calls into one TypeScript program and filters, dedupes, counts, and summarizes right there — handy for data-heavy and mechanical multi-step work. Minimal mode is only terminal plus editor, for testing and comparing baseline performance; minimal context spent on tool descriptions means more room for the task, faster and cheaper. Creator mode customizes DSH itself through conversation: writes plugins for features or UI, combines tools and prompts to assemble your own mode.

Everything is a plugin
https://github.com/topics/dsh-plugin
Same logic: install plugins or ask in chat in Creator mode to write one for you, and it installs and verifies it. Examples from the thread: dsh-zoom for cmd +/- since the stock font limit is 17, a bell on task completion, an RSS aggregator from 30 sources for under 50 cents. The topic already has 17k repositories. The downside people mention: when the core is also plugins, tweaking behavior means dragging ~25 downstream patches.

https://www.youtube.com/watch?v=Zdcx_VHAREI

Creator Mode writes plugins itself from a single prompt — in the demo it assembles a Pomodoro timer in a couple of minutes and drops it straight into the plugin manager, plus it shows slides/web pages from notes in one go, scheduled tasks like a Friday summary, and installing community plugins by name in a couple of clicks with tuning someone else's plugin to fit, while V0.2 is pitched as a full plugin manager, more options for yourself, and two ways to start — Mac/Win desktop or Node with one command.

Discussion
https://news.ycombinator.com/item?id=49929489
Complaints: Electron instead of native, ~/.dsh clutter in home instead of ~/Library/~/.config, third-party plugins as a malware vector, a fake deepseekharness.io site out-SEOing the official one. Some fear the paid API offers no opt-out from training. Praise: cordis as a potential emacs among harnesses for long-lived agents, lightness and speed.

Top comment: desktop enables telemetry by default (unproven, just a comment), while dsh web is explicit feedback only; the commenter says it is fixed by editing cordis.patch.yml with desktop-product-telemetry, product-analytics, and session-log-deepseek: enabled: false.

I got a bonus You've received a CNY 6 bonus credit, valid until October 11, 2026, 3:59 PM Beijing Time. Looks like they hand it out to try the desktop preview cheaply. After my first tests it makes a positive impression.

#deepseek #dsh #harness #desktop

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OpenAI DevDay - Decisions API and GPT-6.1 Sol. New Sonnet 5.5 and Haiku 5.5 models, Mistral Large 4, Gemini 4 Argon.

Gemini 4 Argon. Announced, but no one has it yet. After a long pause, on October 1 Google showed its new flagship: SOTA-level on benchmarks in coding and security. But there is no access yet, so far only the US government and selected testers. https://blog.google/innovation-and-ai/models-and-research/gemini-models/gemini-4-argon/

Mistral Large 4 (Le Chonk). Their first release in a long time, but still far from SOTA models, lagging by about half a year, if not more. So far only paid access via API, with open weights promised for the end of the month. Vibe CLI for coding still runs on Medium 3.5 and Devstral 2 / Codestral, with Large 4 only callable via API. https://mistral.ai/news/mistral-large-4

OpenAI DevDay 2026 — what was shown for coders
https://openai.com/index/devday-2026-recap/
GPT-6.1 Sol — the main model for code. Almost Astra-level in coding and computer use, at a fifth of the price, but reasoning cannot be turned off completely, the lowest level is low. Already set as default in Codex and in Work. https://openai.com/index/introducing-gpt-6-1-sol/

Ultrafast — a paid fast tier. Up to eight times faster output in Codex, up to six times faster in the API, up to three hundred tokens per second. Astra Ultrafast is already available, Sol Ultrafast — coming soon. A new Pro 500 plan was introduced for it.

Sign in with ChatGPT — you can spend your plan in partner services, including Devin, Vercel, Notion.

Codex improvements: cloud work from laptop or phone, shared team environments, updated CLI with voice, /agents view, worktrees, and better scrolling of long sessions. Separately — in-app change review and Codex Security Cloud for checking repos and new pull requests with ready-made fixes.

OpenAI launched the Decisions API on GPT-6 Luna, a direct answer to Jev from TypeSafe - not a conversation, but a quick answer: how true a statement is, what to pick from a list, how to score against a rubric. It runs ten times faster than a regular Responses API response. Unlike Jev, the Decisions API also understands images, runs on the full GPT-6 Luna, so it handles complex cases better, but is more expensive. https://developers.openai.com/api/docs/guides/decisions

Claude Sonnet 5.5 and Haiku 5.5
Sonnet 5.5 came out September 28, Haiku 5.5 — October 7. Sonnet 5.5 is for daily coding work, Haiku 5.5 helps it with small tasks.

Sonnet 5.5 in some computer-use and terminal benchmarks even beats the larger Opus 5.5, but in the announcement its benchmark numbers are from Max mode, which uses significantly more tokens and is generally not recommended for everyday use. https://www.anthropic.com/claude-sonnet-5-5

Haiku 5.5 sometimes matches Sonnet 5.5, compresses conversations well, finds what you need in a pile of logs, cleans up junk before the big model. While the conversation is short, pricing is on par with GPT-6 Luna, but gets significantly more expensive after that. https://www.anthropic.com/claude-haiku-5-5

In Claude Code the short names sonnet and opus now point to 5.5. There is an opusplan mode: Opus makes the plan, Sonnet executes it. Subagents are recommended to keep on Haiku: exploration, compaction, first review of changes.

#claude #sonnet #haiku #openai #sol #codex #mistral #opensource #decisions #jev

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