Agents & Memory Systems

Question 1

The essential difference between a context window and memory is that the window:

Accepted Answer

Is cleared between sessions and bounded within one — The window is working space — fast, small, and gone at session end. Memory is the durable store plus the policy for moving things into that window.

Question 2

"User is vegetarian" is best classified as which kind of memory?

Accepted Answer

Semantic — It is a durable fact about the user with no timestamp attached, which is exactly the semantic category.

Question 3

"On 12 March they cancelled the Berlin trip" is which kind of memory?

Accepted Answer

Episodic — It records something that happened at a point in time, so it is episodic and should be appended rather than overwritten.

Question 4

"Always confirm before sending an invoice" is which kind of memory?

Accepted Answer

Procedural — It encodes how to operate here — a learned workflow rule, usually installed by a user correction.

Question 5

When a semantic memory is contradicted by new information, the correct action is to:

Accepted Answer

Overwrite, since there is one current truth — Preferences and facts have a current value. Keeping both is how an agent ends up acting on a preference the user abandoned a year ago.

Question 6

Episodic memories are appended rather than overwritten because:

Accepted Answer

Both events genuinely happened — A later event does not make an earlier one untrue. The cost of appending is a growing log and noisier retrieval, not incorrectness.

Question 7

The four memory operations are write, retrieve, forget and:

Accepted Answer

Consolidate — Consolidation merges duplicates and resolves contradictions. It is the operation most often omitted and the reason long-lived agents degrade.

Question 8

Writing every conversation turn into memory is harmful because:

Accepted Answer

The store becomes a transcript and top-k fills with chatter — Retrieval degrades to search over noise, and the one durable fact you needed ranks eighth. An explicit extraction step is what keeps the store useful.

Question 9

Which memory operation is the one that costs tokens on every call?

Accepted Answer

Retrieve — Retrieved memories are injected into the context window, so retrieval is bounded whether you bound it deliberately or discover the bill later.

Question 10

Setting the recency weight very high in a retrieval scorer causes:

Accepted Answer

The newest memories to rank first regardless of the question — A question about food can then retrieve a payment preference and drop the dietary fact — recency is a good tiebreaker and a poor primary signal.

Key insight

Which memory does this belong in?

Test your knowledge

The essential difference between a context window and memory is that the window:

The short version

In more depth

Agents & Memory Systems

Four kinds

Four operations

Retrieval scoring

Failure modes

Interview Questions

References & Further Reading

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