Dev log 9: keeping the payloads off the log, and proving it with vectors another implementation can run
Part 12 of the Cairn series. Dev log 8 closed the loophole for agents that never held a grant. Since then there have been four changes, each audited by Gemini and by OpenAI: invariant I4 for the require-grants switch, hash-only action payloads, durable storage for the secrets those payloads leave behind, and language-neutral test vectors for all of it. This post covers all four, every audit round, and what the audits got wrong and right. Why this round exists Until now an ACTION entry on the log pointed at its arguments and its result by hash, and the blobs behind those hashes were published with the log. That is the right default for governance, because the replay has to read proposals, votes and grants. It is a poor default for what an agent actually did. A web fetch carries a URL. A tool call carries whatever the model decided to put in it. Putting every argument and every result next to a public log is a privacy problem that nobody asked us to create. The fix has to keep two pr...