case studies
How to Develop Against a Metered or Rate Limited API With CodeInstances
Some APIs you can’t call as often as you’d like. A payments sandbox that throttles you after a burst. A maps or weather API billed per request. A …
Posts
case studies
How to Replay the AI Agent Run That Did Something Odd Last Night
An agent ran overnight on a batch of tasks. In the morning one result is wrong. It filed a ticket under the wrong customer, or summarised a document it never fetched, or …
case studies
How to Upgrade a Dependency With CodeInstances Replaying Real Runs
You need to bump something underneath your program. A new major version of the HTTP client library, a vendor’s SDK, or the Go toolchain itself. The changelog is …
format
The CodeInstances File Format Is Open JSON With a SHA-256 ID
The file is the product. A tool can be replaced, but a run you kept in a format only one tool reads is a run you’ll lose eventually. So the instance format is open …
explainer
What a Code Instance Is and Why Program Runs Should Be Kept Like Code
If you’ve written object-oriented code, you already know the idea. A class is a blueprint. Each object you make from it is an instance of that class, with its own …
ai agents
Why Replay Matters for AI Agents That Take a Different Path Every Run
Most programs are boring in a good way. Give them the same input and they do the same thing. If one fails, you can usually run it again and watch it fail again. An AI …
the name
Why the Project Is Called CodeInstances
The name is the idea, in two words. Code is the program you write. An instance is one run of it. Programmers already use “instance” this way. An object is an …