Very cool!
Yep, a constantly updated spec is the key. Wrote about this here:
https://lukebechtel.com/blog/vibe-speccing
I've also found it's helpful to have it keep an "experiment log" at the bottom of the original spec, or in another document, which it must update whenever things take "a surprising turn"
We found, especially with Opus and recent claude code that it is better/more precise at reading existing code for figuring out what the current status is than reading specs. It seems (for us) it is less precise at 'comprehending' the spec English than it is the code and that will sometimes reflect in wrong assumptions for new tasks which will result in incorrect implementations of those tasks. So we dropped this. Because of caching, it doesn't seem too bad on the tokens either.
I'm still sharing this post in the internal org trainings I run for those new to LLMs. Thanks for it - really great overview of the concept!
I saw in your other comment you've made accommodations for the newer generation, and I will confess than in Cursor (with plan mode) I've found an abbreviated form works just as well as the extremely explicit example found in the post.
If you ever had a followup, I imagine it'd be just as well received!
Looks like default OpenCode / Claude Code behavior with Claude models. Why the extra prompt ?
Honest question: what do you do when your spec has grown to over a megabyte?
Some things I've been doing:
- Move as much actual data into YML as possible.
- Use CEL?
- Ask Claude to rewrite pseudocode in specs into RFC-style constrained language?
How do you sync your spec and code both directions? I have some slash commands that do this but I'm not thrilled with them?
I tend to have to use Gemini for actually juggling the whole spec. Of course it's nice and chunked as much as it can be? but still. There's gonna need to be a whole new way of doing this.
If programming languages can have spooky language at a distance wait until we get into "but paragraph 7, subsection 5 of section G clearly defines asshole as..."
What does a structured language look like when it doesn't need mechanical sympathy? YML + CEL is really powerful and underexplored but it's still just ... not what I'm actually wanting.