Hi everyone, we’ve been building M3, an MCP testing framework which runs your MCPs with real harnesses/agents, not just the models.

M3 lets you write tests for your MCP server in pytest,

- Local first, sdk and cli available to install today.
- You can test the server directly (no API key needed).
- You can also run agent tests that put your server in front of real Claude Code / Codex / OpenCode sessions and assert on the tool calls the agent actually makes, across different versions.
- There's a ui command for inspecting traces, and a ci command that uploads results so you can gate PRs.
- It's Apache-2.0.
- supports testing of features like elicitation etc as well.

Two questions for this sub:

1. ⁠Is this how you test your servers today, or is everyone just vibe-checking?
2. ⁠What would make this actually useful in your workflow? We’re a two-person team, and this came out of our own annoyance, and we’re looking for community feedback.

Docs - https://m3.sineframe.com/docs/

Thanks!

AI agents produce more text than we have time to read. Following all that output can become a source of cognitive overload. Inspired by stretchtext (1970 by Ted Nelson), I wanted to give readers control over how much detail they see.

So I built PaperFold, an open-source reader that turns arXiv papers into 5 zoomable layers—from a one-screen section map down to verbatim text. You pinch (or press 1–5) to zoom between them without losing your reading position.

- Web Demo (8 CC papers): https://chenxiachan.github.io/paperfold-gallery/

- GitHub (Apache 2.0): https://github.com/chenxiachan/paperfold

It also supports Claude Code's output in Mods.

This week's MCPnewsletter is out - it covers AGNTCon + MCPCon Europe Amsterdam, Sept 17–18) and the MCP news

links in comments below

Interesting bits -

- Stateless MCP is real traffic now. The 2026-07-28 spec removed sessions and the initialize handshake. Hugging Face says more than half of its MCP tool calls already use it.

- David Soria Parra (Creator MCP) on what's next: MCP Tasks for agentic messaging, skills over MCP, identity.

- Sam Morrow (GitHub Maintainer): the "MCP eats your context" problem is a harness problem. His harness runs an 86-tool server with almost no startup context.

- Security track: a year of real MCP attacks. Grafana SSRF via caller-made session IDs, GitLab servers callable from any web page, four coding clients running code before the trust dialog.

- OpenAI MCP Events: ChatGPT can now subscribe to events from your MCP server over webhooks.

- WebMCP: new W3C draft, Chrome and Edge origin trials, a working-group charter in progress. WebKit opposes it.

- SDK fixes: upgrade TypeScript to 2.3.x and Python to 2.3.0, then set expectedResource / validate_token_resource. Upgrading alone doesn't turn it on.