Secondary Source
Sumber Sekunder
An account of a primary source, one step removed. Cheap to load, lossy by construction.
A secondary source is an account of a primary source, one step removed: a summary, a doc page, a compaction summary, a colleague's explanation. It is cheap to load and it is lossy by construction, because someone chose what to include and what to leave out.
That is fine for orientation and dangerous for facts. A secondary source tells you roughly what is in the code; it cannot tell you exactly what a function returns. When the answer matters, follow it to the primary source and check.
The compounding problem is that summaries of summaries lose more each time, and a chain of them can end up describing a system that no longer exists. A compaction summary is a secondary source; a handoff document that quotes a compaction summary is a third-order source. This is the practical argument for keeping the original artefacts reachable rather than only their descriptions.
Related terms
Primary Source
The thing itself: code, transcripts, raw data. Complete and authoritative, but expensive to load.
Compaction
Summarising the old conversation so the new part fits in the window.
Handoff Artifact
A document used as the carry mechanism for a handoff: written by one session, read by another.
Grounding
Tying the answer to something checkable, so it can be verified instead of trusted.
Context Rot
What happens when a context keeps everything: it grows, and the useful parts get harder to find.
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