A thread you can test
Context
4 notes move from the word to a real choice at work — understand it first, then decide whether to use it.
Each note stands alone, or becomes the next step in this thread.
THE QUESTION THIS PAGE ANSWERS
ANSWER FIRSTWhat is Context, and which AI decisions does it change?
Before Codex stuffs anything into model context, it first mints a type for each injection: the type knows its own role, marker, and body; assembly sorts by fields; later the same marker pair claims it back This page keeps the related concepts, common mistakes, and practical notes in one reading thread.
First decide whether you are blocked by a definition, a choice, or verification; then choose the closest of the 4 notes below.
Start with “Before You Stuff Context, Give It a Type,” then restate the conclusion using your own task.
Do not treat every method in a topic as interchangeable. The answer changes with the input, risk, and acceptance bar.
THIS QUESTION THREAD
Put the word back inside the choice it changes.
Before You Stuff Context, Give It a Type
Before Codex stuffs anything into model context, it first mints a type for each injection: the type knows its own role, marker, and body; assembly sorts by fields; later the same marker pair claims it back
Write Context Governance into Code Review
A type system cannot police length, frequency, or prefix stability. Codex writes six bans into AGENTS.md, copies them into the code review skill, and lets review hold the cost after the type has already passed
After the Window Fills, What Gets Cut and What Stays
Codex splits compaction into three timings times three implementations. Remote results hit a filter first; a mid-turn summary must sit as the last history item; flip the empty-window switch and memory does not come along
JSONL Is the Truth, SQLite Is the Mirror
The session writes as it runs. JSONL is the original. SQLite is a rebuildable cover. After a mid-run power cut, resume reads the file; the list can degrade