Proposal: Adopt OpenRPC for ACP Interfaces

[zcstarr]

Proposal: Adopt OpenRPC for ACP Interfaces

Background
ACP (Agent Client Protocol) defines JSON-RPC methods for Zed agents. Right now, the interface descriptions are somewhat ad-hoc with a json-schema which is good, but their is a more robust way to describe the interfaces potentially with OpenRPC. OpenRPC is a mature, JSON-RPC equivalent of OpenAPI that would let you:

• Formally specify request/response schemas
• Generate client/server stubs, docs, tests
• Validate payloads against the spec

OpenRPC is already used by Minecraft, Ethereum Foundation, MetaMask, Bevy, and others.

What I’d like to do

1. Define ACP’s JSON-RPC schema as an OpenRPC document.
2. Integrate with our build: codegen validation, docs.
3. Collaborate on a migration plan (minimal breaking changes).

Why it helps

• Single source of truth for methods, params, results
• Improved DX for integrators (autocomplete, snippets)
• Built-in tool ecosystem (doc viewers, codegen)

Resources

• Spec repo: https://github.com/open-rpc (Apache 2.0)
• OpenRPC website: https://spec.open-rpc.org//
• Talk (OpenAPI Conference 2024):
  https://www.youtube.com/watch?v=9UiKQ1zasjE

I’m one of the OpenRPC co-founders and happy to help draft a spec. We're actually in the middle at the start of a big overhaul and it would be great to be able to support ACP. I'd love to speak further about this and answer any questions or just talk concerns or prototypes !

[benbrandt]

@zcstarr thanks for reaching out! We looked into this and are definitely open to it.
What would be really nice is if there is a great way to auto-generate this from the code like we do with JSON-schema (and also generate code from the schema)

We currently do:

• Rust -> JSON Schema
• JSON Schema -> Docs/TS

We're still very new to OpenRPC, so if there are pointers in how we can do this, let us know.

[zcstarr]

That's one area we're looking to invest more tooling into, we have tools to do the auto generation from go lang -> open-rpc from code, but we haven't done this for rust yet. I believe there are few folks in the community that have rolled their own generators in rust, which could be a possibility.

That said, this would be something the team would be into. Maybe the first step, that would be interesting and place to discuss possibilities, would be to translate the current spec into OpenRPC.

That would give us a baseline for what we'd maybe ideally want to generate from rust code and a way to talk about the spec. I'll try and ack back soonish with what I think would be the current spec in OpenRPC, that will also give me some time to dive a bit deeper into the acp code and dig around a bit.

[vavans]

Did you consider https://typespec.io to describe apis with a strong type system ?
There is an emitter to jsonschema as well, and code generators too.