A new EDIT tool for LLM agents

Right now I'm working to an agent for my DS4 project. Local inference is token-poor, it's a battlefield where optimizations count. I was quite surprised by the fact the EDIT tool everybody is using right now forces the LLM to emit the old version of the text verbatim. This CAS (check and set) mode of operation, where I say EDIT old="foo" new="bar", is needed because there are often colliding edits (the user is editing as well, or checked out a different branch, and so forth) and because the LLM can just hallucinate that a given line had a given content. This means, basically, that just using line numbers is very fragile: to say, change line 22 with new="foobar" is not good. Yet I don't want my local LLM to throw away tokens rewriting the old text each time, also because certain times the old text has a lot of special chars and spaces that the model may get wrong, forcing it to do the same edit again. So I designed a tag-based EDIT tool that is still CAS style, but more tokens…