The good news that I hear here is that ACP is likely easier to implement than I think.
I am going back through the reference implementation and refactoring my interpretation of ACP itself and will move forward on this until I hit a wall, to try and understand by doing... time allowing.
A jump-off point in the meantime is that the reference implementation immediately hits upon npx being in-path, which I keep running into in the editor itself. A key to my portion is Bun which might be out of scope for SCP but still falls within Zed because it seems node primacy was cherry-picked and hard-coded.
[ For example, my linter is always on the fritz, all my environments set for Bun in Typescript projects behave weirdly, but just enough to work... plus performance is subpar with node by a lot. ]
I feel like understanding ACP now and getting smoothly into that is essential so I am extremely grateful @benbrandt and do not mind haircutting my */OSS enthusiasm to focus on ACP directly.
Will be re-reading this 10x: https://github.com/zed-industries/agent-client-protocol/tree/main/typescript/examples