AI agents are moving amazingly fast — but they could be moving even faster. Today's agents are monolithic: one vendor controls the model, the tools, and the context pipeline. That works, but it leaves an enormous amount of potential on the table. Every time we've opened up a platform — web APIs, app stores, game modding — the result has been an explosion of creativity that no single team could have anticipated. AI agents deserve the same openness.
This talk introduces "agent mods" — portable extensions that teach AI agents new tricks, built on the Agent Client Protocol (ACP). Agent mods go beyond MCP servers, skills, and hooks: they can inject context, provide examples, intercept messages, and transform tool output. And, because ACP is vendor-neutral, agent mods work across any ACP-supporting agent. Using Symposium, an open-source project that brings agent mods to the Rust ecosystem, I'll demo how agent mods can extend the user experience in all kinds of ways, and make the case that an extensible, community-driven approach will produce better agents than any closed system can.
Interview:
What is the focus of your work these days?
My time is split between Rust language development — I co-lead the Rust language design team — and building Symposium, an open-source platform for agent mods built on the Agent Client Protocol. Symposium is my effort to put Rust at the forefront of agentic development by tapping into the creative energy of Rust developers writ large.
And what was the motivation behind your talk?
When I started using AI agents, I was blown away by what they could do — but I immediately wanted to open up the hood and start tinkering. I love tools like VSCode or Emacs that grow rich ecosystems of extensions, and I wanted the same thing for agentic development. But the existing extension mechanisms were either incomplete (MCP servers and skills can add tools and context, but can't deeply shape agent behavior) or non-portable (hooks and plugins are tied to a single agent). When I found the Agent Client Protocol, I realized it could provide the foundation for powerful, portable extensions — and agent mods were born.
Who is your talk for?
Anyone using or interested in AI agents. My whole thesis is that we want people to be able to control and contribute to their own agentic experience — you never know who's going to invent the next big thing. No Rust experience required; Rust is the proving ground, but the ideas and protocol are language-agnostic.
Speaker
Niko Matsakis
Senior Principal Engineer @Amazon, One of the Lead Designers of the Rust Programming Language, Creator of Symposium (symposium.dev), Project Director on the Rust Foundation Board,
Niko Matsakis is one of the lead designers of the Rust programming language and co-lead of the Rust language design team. He is a Senior Principal Engineer at Amazon and a Project Director on the Rust Foundation Board. He is the creator of Symposium (symposium.dev), an open-source platform for agent mods built on the Agent Client Protocol.
