XKV, the studio’s twenty-second project, is for the small values that cause big trouble: credit limits, prices, timeouts, feature switches, and the settings AI agents now change on their own. A normal store keeps the value and forgets the story. XKV makes every write say who made it and why, and lets it name the earlier changes that caused it, on any key. Ask a value why and it walks the chain back. A credit limit of 50 points at a risk score of 0.82, which points at a card dispute billing recorded from a bank notice.
0.1.0 ships the Go package, the xkv command with an HTTP mode for other languages, and a live demo running the same code as WebAssembly. A write without a reason is refused unless the store is opened as relaxed. Causes are checked before a write lands. Compaction drops old revisions but keeps every one a kept value points at, so a chain that worked before still works after. Four case studies act the idea out, from an incident timeout to an AI agent’s cache change.
The testing went after each promise. A writing process was killed 1000 times and lost none of its 53,701 acknowledged transactions. A torn last write was cut at each of its 397 byte positions, and every open trimmed back to the last whole transaction. A million revisions opened in 181 ms with the index snapshot and compacted from 124 MB to 5.2 MB with every chain intact. An independent review came before the release, and each finding has its own test. It’s one Go package and one file, open source under Apache 2.0, with binaries for Linux, macOS and Windows. Multivergence keeps the branches an agent might take; XKV keeps the reason behind the one it did.