I'm not sure why almost all codemode implementations choose Javascript. I prototyped an agent[1] to use bash as the language for codemode, which in my opinion worked equally well and requires no teaching (there is literally 0 prompt to teach the LLM about codemode. A tool named "bash" is enough to have them know the usage).
> However bash has one fundamental limitation which is that it can only compose programs that run. And there are some things, which are not programs, but native tools to the LLM and they sort of have to be.
The most obvious example here is `read` or `view_image`. If a multimodal model needs to read an image, it cannot use cat for that because the harness needs to inject the actual image payload into the protocol of the LLM.
Does your prototype overcome the limitations mentioned in the article?
> I'm not sure why almost all codemode implementations choose Javascript
Because the models are trained on JavaScript for code mode. You get away with way fewer instructions. They also want to be able to express concurrency and that works very well with the Promise global.
But a big reason is that code mode runs on the harness side so bash is a tricky target in particular.
How is this different to Claude writing mini scripts to get jobs done which it does quite often?
I'm not sure why almost all codemode implementations choose Javascript. I prototyped an agent[1] to use bash as the language for codemode, which in my opinion worked equally well and requires no teaching (there is literally 0 prompt to teach the LLM about codemode. A tool named "bash" is enough to have them know the usage).
[1] https://github.com/ylxdzsw/mu
> However bash has one fundamental limitation which is that it can only compose programs that run. And there are some things, which are not programs, but native tools to the LLM and they sort of have to be.
The most obvious example here is `read` or `view_image`. If a multimodal model needs to read an image, it cannot use cat for that because the harness needs to inject the actual image payload into the protocol of the LLM.
Does your prototype overcome the limitations mentioned in the article?
> I'm not sure why almost all codemode implementations choose Javascript
Because the models are trained on JavaScript for code mode. You get away with way fewer instructions. They also want to be able to express concurrency and that works very well with the Promise global.
But a big reason is that code mode runs on the harness side so bash is a tricky target in particular.
Can do you make a tool or mcp call from bash?
Yes. Invoking an MCP tool is just an HTTP call. You can do it with curl.
That's one kind of MCP. Another is a local stdio server.
Also there are things like subagents, etc (which may be considered tools).
subagents differ: in my claude code logs every subagent cache write is 5-minute tier, main session 1-hour
Recovery after interrupted execution; distinguishing completed side effects from calls that can safely repeat.