Is spec driven development the silver bullet?
Nikos Katsikanis - 4 October 2025
Spec driven development (SDD) is a term I came up with my self last week and I decided Google it, then found out that Microsoft already coined the term, ah well. I experimented with it last week for a new social network I drempt up. I had the dream of handing an AI a huge spec and waking up to polished code, yet the results were disappointing..
The overnight spec dream versus reality
I tested the approach on a social network concept that listed roughly thirty features. The agent shipped maybe two thirds of them, but the working pieces still needed plenty of cleanup. The spec itself went ignored almost immediately by the agent I was using and I keep having to remind it to check the spec. I was using a mixture of Warp Terminal, Gemeni Pro and Codex CLI.
I also noticed that people struggle using SDD when they are not checking every single line of code that is gradually introduced by spec. If you ought to use SDD, you have to piecemeal add in each new spec to your agent. Let's say one serious feature at a time or three new minor ones at a time.
So given this Limited experience I cannot recommend using big bang SDD for any serious project as a long term single source of truth or delevering multiple feature at once within a single agents context prompt.
Where specs still earn their place
I do not treat specs as villains. They shine when garthering initial requirments from clients. In those engagements I treat the document like a MVP waterfall snapshot and then begin to implement them gradually, they also help save on argumetns later on. Later you can expose the specs generated via the code via help dialoues. Eventually the orignal specs will go live in some stale place like basecamp etc to die.
Experimenting with ai-agent-toolkit
This curiosity is also why I started ai-agent-toolkit. The project combines specifications with Docker environments so agents can spin up sandboxes in unrestriced mode (skipping yes prompts).
Week-one takeaways
After seven days of focused experiments I am not calling spec driven development a silver bullet. It is another tool in my kit, and I reach for it when regulations, teams, or integrations demand a paper trail. For my own ideas, keeping code as the single source of truth still feels faster and calmer.