Name the constraint correctly
| Term | Usually means | Do not assume |
|---|---|---|
| Token | A model-specific unit of encoded input or output | One token equals one word |
| Credit | A service-defined allowance or billing unit | One credit has the same value everywhere |
| Rate limit | How much activity is allowed during a time window | It is the same as a spending cap |
| Usage cap | A plan, budget or policy ceiling | Unused capacity carries forward |
| Context limit | How much information a model can consider in one interaction | All available space should be filled |
Compare services with a common task
A plan described in credits cannot be compared directly with token-priced access until you know what actions consume a credit, whether different models consume different amounts, and which limits apply. Run the same representative task and record accepted completions per unit of spend and per unit of time.
Also record what happens at the limit. A request may queue, fail, switch model or require a higher plan. That operational effect can matter more than a small difference in nominal unit price.
Ask before committing to a plan
- Which inputs, outputs, tools and retries are metered?
- Are limits per user, project, model or organisation?
- What resets, expires or rolls over?
- Can usage be exported and attributed to a task?
- What happens when a cap or rate limit is reached?
- Can a budget alert or hard ceiling be set?
Keep accounting separate from value
Commercial units change. A durable measurement layer keeps your task ID, result status, latency and review outcome stable while mapping each provider's usage fields separately.
Sources & further reading
- Models
OpenAI Developers. Official model-selection documentation, checked 13 September 2026. Product names, capabilities and prices can change; the collection uses the durable principle of matching capability to a task rather than prescribing a current model.
- GenerationConfig REST resource
Google Cloud. Official documentation showing that output-token limits are a controllable generation setting. Parameter names and behaviour are provider-specific.
Examples and exercises are illustrative unless attributed to a source. No independent expert review is claimed.
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