Your agents only ever see what's in force today.

Effective-dated. Not just stored.

A folder, a wiki, a vector store, a SharePoint site: the only date any of them acts on is when a file was last saved. You can write an effective date into the document, but then it's the model's job, on every call, to notice it, compare it to today and pick the right version. Nothing checks its choice, and afterwards a trace shows what it picked, not what was in force.

Schedule

Set when a change takes effect, and it goes live at that moment with nobody at a keyboard. A correction is just publishing the previous text forward — there's no rollback button because there doesn't need to be one.

Gate

Drafting and publishing are separate roles — for documents, for prompts, and for the tool metadata your agent reads. And the model itself can't choose which version of reality it gets: the moment on both timelines and the library are fixed on the connection, not arguments a prompt — or a document it's reading — can change.

Prove

Every version is kept on two timelines: when it was true, and when you knew. A trace tells you what one conversation got back. This tells you which version of reality the agent had access to that day, and when you knew it — so a dispute isn't “find the right log”, it's “this is what we were serving, and here's when we knew.”

Questions engineers ask

Can't we just add a date column?

You can, and it fixes the “not in force yet” case. It doesn't give you the second timeline — what you knew, and when — which is what you need to explain a trace after a correction has landed: was the agent served a stale policy, or the right one for what was published at the time? It also can't prove a version was never live. Nor does it give you an append-only history, a draft → ready → publish gate with separate roles, scheduled go-live, or an MCP endpoint that resolves all of that before the model sees anything. EffectiveFrom is those controls out of the box, not a schema suggestion.

Does the model see the effective dates?

No. get_content takes a key and nothing else. Which library, and which moment on both timelines, are set once on the connection by whoever configured it. Dates inside your documents are served as written; it's the version bookkeeping the model never sees.

Is this a CMS?

No. There's a markdown editor and a publish workflow, and that's where it stops. It's the layer between whatever you author in and whatever your agent reads from — thin on purpose.