What a retention window deletes

A retention setting that deletes messages and keeps everything else is not a retention setting. It is a tidy inbox.

This page explains what a conversation actually contains, what a window has to remove for the setting to mean anything, and why business definitions need a separate rule.

What is in a conversation?

Four things, and only the first is visible.

1. The messages. Your questions and the assistant's answers.
2. The tool calls. Each query the assistant ran: the table, the filters, the fields.
3. The tool results. The rows those queries returned. This is your ledger data, sitting in the conversation.
4. The attachments and the files. Anything uploaded, and anything generated, such as a spreadsheet or a PDF.

Item 3 is the important one. When a finance team worries about a conversation, they are worried about the rows, not about the prose. A retention window that deletes only items 1 and 4 leaves the data behind.

What does the window delete?

The conversation with its tool calls and its tool results. Not archived, not anonymised, and not moved to cold storage.

Each customer company sets the window. The range is 1 day to 365 days, and the starting value is 14 days. A daily job removes what has passed the window. The change to the setting is itself recorded in the audit log.

How long should the window be?

There is no correct answer, so decide from how your team works.

Short, between 1 and 14 days. Right for companies that treat conversations as working notes. The answer gets acted on, and the conversation has no value afterwards. This is the lowest-exposure option and the default for a reason.

Medium, between 30 and 90 days. Right for teams that revisit their own analysis across a quarter. It also suits a team that has to show how a figure was derived when somebody asks a month later.

Long, up to 365 days. Right when the conversation is part of how the team documents its reasoning. Understand that you are choosing to hold ledger rows for a year in a second system.

One rule regardless of the number: do not choose a long window because you might want the definitions later. Definitions have their own setting, which is the next section.

Why do business definitions have a separate setting?

Because a definition is not a conversation.

When your team settles what "overdue" means, that fact is true next year. If it expired with the chat that produced it, the assistant would relearn the same definition every fortnight, and it would ask your team the same question every fortnight.

Knowledge entries therefore have their own retention setting, and no expiry by default. Left alone, an entry lives until the loop retires it: superseded by a better entry, denied on review, or marked stale because the query behind it stopped returning data.

You can set a window on knowledge anyway. The product warns you first that definitions which are still correct will be deleted too, because that is the real consequence and it should not be a surprise.

Retention and the bookkeeping rules

A question comes up in every Danish conversation about this: if bookkeeping records must be kept for five years, can a 14-day window be right?

Yes, because the two things are different. The bookkeeping system is the record. Business Central holds the entries, and the retention rules apply to it. The conversation is a working note about that record, and deleting the note does not delete the entry.

The confusion is worth resolving explicitly with your auditor once, because the answer shapes the setting. If somebody treats the chat as the audit trail, the system design is wrong, not the retention window.

Danish companies have a second reason to keep the boundary clean. Since 1 January 2026, the digital bookkeeping requirement extends to sole proprietorships and associations above 300,000 kr. in net revenue for two consecutive years. The registered bookkeeping system is the record. An assistant reads it.

What to check in any product

1. Does the window delete the tool results, or only the messages?
2. Who sets the window: you, or the vendor?
3. Is the change to the setting recorded?
4. Do business definitions and memories follow the same window, and can you choose separately?
5. What happens to generated files and exports?
6. Can you prove a deletion happened?

Question 1 is the one that separates a real setting from a feature list entry. Ask it first.