📖What it means

A slot is the pairing of a SUBSCRIPTION and a MODEL: the thing a track actually runs on. Neither half answers the question alone. One subscription serves several models, and since one model sits on more than one subscription (claude-opus-5 is held by both the Claude AI Max plan and the metered Claude API). So 'which subscription' and 'which model' are two answers, and the slot is the pair written as subscription/model, for example anthropic/claude-opus-5.

A track is REGISTERED FOR a slot and then RUNS IN it. Registration is per pair, because both halves change what the work can do: a different model on the same subscription changes the ability and the temperament, and the same model on a different subscription changes the account, the allowance and the ringfence. Ninad ruled on 2026-09-19 that putting a track on a slot it has never run on is a genuine risk and its own first step, ending in a recommendation on whether it is safe to proceed -- never a silent move.

The slot is not a new store. It is already carried as the provider and model on a service track, and as the (provider, model) key of the model register. What was missing was the word, so surfaces that meant a slot said 'lane' and readers had to guess which sense was intended.

AMENDED 2026-09-27 (Rulings Repo cost-center #172, design 682 v1.2): a slot becomes ITS OWN RECORD -- subscription (from Procurement's register), model, the adapter that serves it, its sign-in kind, its keeper and its state -- and a track points at one slot and knows nothing else about it. The sentence above that 'the slot is not a new store' was true until then and is kept as history; the record is built by arc CAROL-ARC-0029 phase 3.

📖Easily confused with

[{"term": "Track", "distinction": "A track is a line of work inside a service, with an owning agent and a budget; it is the thing that HOLDS a slot. A slot is what it runs on. 'This track moved to another slot' is the sentence that needs both words; naming the pair a track would make it 'a track runs on a track'."}, {"term": "Lane", "distinction": "A lane is an execution route and says WHO executes under what accountability -- the planner, the Orion bypass, the Albus bypass. A slot says what the work runs ON. Two lanes can share one slot, and one lane can carry tracks sitting in different slots."}, {"term": "Subscription", "distinction": "A subscription is the thing paid for, at least once. A slot is that subscription together with one model on it, so one subscription contains several slots and they are not interchangeable."}, {"term": "Channel", "distinction": "A channel is the route a message travels between a person and an agent -- WhatsApp, web chat, email, the CLI. It decides who can be identified and what may be sent. A slot decides what runs the work and who is billed for it; the two never substitute."}, {"term": "Lane concurrency limit", "distinction": "The model lock's concurrency 'slot' is a permission to run RIGHT NOW, one of a fixed number, released when the call ends. A slot in this sense is a standing subscription-and-model pairing that does not empty or fill. Where both could be meant, say 'lock slot' for the first."}]

📖Nuance

Written subscription/model with a slash, the form the readiness surface already prints. The estate's word for the subscription side is the provider key (anthropic, claude, codex, openai, gemini, kimi, ltx); the label a person reads -- Claude API, Claude AI (Max) -- belongs to the subscription record and is not part of the slot key. Ninad chose the word on 2026-09-19 from track, channel and slot: the first two were already load-bearing entities, and a third sense of a live word is refused in Carolverse.

📖Also called

- subscription/model
- subscription and model pair
- provider/model

📖Filed under

Category: work.

Service: Governance.