Reading the column
The context ring
How much room is left in a session, which model is holding it, and the three different kinds of silence.
Beside every lamp sits a smaller ring. The arc is how much of the model's context window that session has spent, and the letter in the middle is the model family: O for Opus, S for Sonnet, H for Haiku, F for Fable, M for Mythos, G for the GPT family Codex runs, and n for a model this build has no window for.
G and not 5, because a digit in a column of letters reads as a version number.
The three silences are not the same silence
An empty ring would say there is room, which is the one thing none of these cases says. So each gets its own mark.
- exact
A reply carried a token count, and nothing since has changed it.
- at least
The arc is paler and the figure carries ≥. Only a reply carries a count, so whatever was loaded since is invisible.
- nothing read yet
A dashed circle. This session has not replied, or its transcript is not there.
- void
A solid circle, a dimmed letter, no arc. The session was compacted, so the figure describes a conversation that no longer exists.
Where the denominator comes from
For Claude Code it was measured rather than assumed. The app has a table of window sizes per model, and a script that measures the point at which a real session compacts.
For Codex it is not measured at all. Codex writes model_context_window into the same record as the token count, so a Codex percentage rests on nothing of ours: no table, no calibration, nothing a vendor can invalidate without telling anybody. The card says declared so you know which of the two you are reading.
- where
- this Mac · ~/work/docs-site
- model
- GPT-5.6
- context
- 17.0k / 258k declared
- slot
- 6 · lampboard open 6
Codex reports no failures: a turn that fails stops speaking.
Why it replaced the slot number
The cell to the left of the name used to carry the row's keyboard slot: a number that never changes, on a row whose position never changes either. It answered a question nobody asks twice.
Occupancy is the opposite kind of fact. It moves while you work, and it decides whether to start a large task in this session or a fresh one. The slot did not disappear, it moved into the card, where a fact you look up once belongs.