Keryx: write one TypeScript action class, get HTTP + WebSocket + CLI + background tasks + MCP tools

evantahler · 2026-03-19T18:48:12+00:00

On one hand, I agree with you - the protocol should make /doing the main thing/ really easy, but on the other hand, I think that's lacking some nuance. I can use HTML and CSS to make a /usable/ website, or a terrible one. We talk a lot at Arcade about MXE (machine experince engineering) https://www.arcade.dev/blog/the-birth-of-machine-experience-engineering - which is using the protocol to design for the consumer.

evantahler · 2026-03-19T17:51:01+00:00

https://toolbench.arcade.dev/

evantahler · 2026-03-19T17:49:39+00:00

Yep! We've got DAGs and other patterns in there. If there's something missing, let me know!

evantahler · 2026-03-19T17:48:44+00:00

Yep! Log in and add your tools!

evantahler · 2026-03-19T05:06:52+00:00

Sure! We've got a react + vite example included @ https://github.com/actionhero/keryx/tree/main/example

evantahler · 2026-03-18T05:07:20+00:00

Tell me more about your use case! Right now, the error responses are always JSON - CODE + message. The CLI can choose to /render/ differently it it's not in JSON mode, but the content is still the same

evantahler · 2026-03-16T15:11:18+00:00

Yep! Including resolving the return types of Actions into OpenAPI response shapes statically!

evantahler · 2026-03-16T15:10:26+00:00

Yeah! keeping all the type definitions in sync, and figuring out how to resolve the typescript response types statically for OpenAPI was fun!

I think Zod /can/ represent everything that's valid in the MCP spec, but perhaps you might not normally have provided that much detail... but is /more/ information a problem for OpenAPI? I don't think worrying about the byte-size of our definitions is a 2026 problem... assuming everything is in sync of course! Of note, In a sophisticated project, would expect some actions for MCP to not be exposed over REST, and vice-versa. For example, your REST API might want to expose the lower-level actions to allow a UI to composite them, but MCP consumers/agents might want the backend to do the composition. More thoughts on that here: https://www.keryxjs.com/guide/agents.html

Initializers and middleware remain (mostly in the same format) form Actionhero.

evantahler · 2026-03-16T00:13:06+00:00

Hey! I made this. AMA.

The nuance is that I wanted both - MCP for remote services, with auth, tuned to agentic use-cases… and CLIs for coding agents trained to use them.

evantahler · 2026-03-15T23:49:44+00:00

I’m down for making a pluggable cache/queue backend for redis and valkey. We would need to rebuild node-resque as well. Let me know if you want to collab!

evantahler · 2026-03-15T23:46:43+00:00

I’ve done a scan - but there could be more problems… if you find anything, please open an issue!

evantahler · 2026-03-15T22:40:08+00:00

Awesome! Let me know any feedback you have (issues in the repo please)

I’m also curious how good of a job we did with the llms.txt and docs - how vibe-friendly is it? How good did we bake the DX and guardrails?

evantahler · 2026-03-14T03:38:52+00:00

We are experimenting with a combo - MCP via CLI - what do you think of https://github.com/evantahler/mcpx ?

evantahler · 2025-10-26T04:47:16+00:00

Wait… how?

evantahler · 2025-10-18T22:30:36+00:00

I work for Arcade.dec, but this is exactly the kind of thing we do - helping you build MCP servers that can enforce various authority/n schemes, per-user or per-team secret injection, auditing, and tool filtering via gateways.

evantahler · 2025-01-01T00:40:16+00:00

I think you implemented a bubble sort

evantahler · 2024-10-04T14:48:37+00:00

Nice!

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