Sponsored partner brief
The 158 ms call boundary
Sponsored by Celeris. The benchmark results in this issue were produced and originally published by the Celeris team.
Agentic workflows do not wait once; they wait at every model call. Celeris-1 is a diffusion language model built for repeated, structured steps such as routing, extraction, scoring, and query rewriting. In Celeris’s provider-run MMLU-Pro test, it scored 75.9% at a 158 ms p50 server response time. A separate long-form run measured 1,664 output tokens per second and 0.58 seconds for a complete response.
Provider-run measurements
- 75.9%
- MMLU-Pro, full test set, five-shot chain-of-thought, strict scoring, reasoning budget set to zero
- 158 ms
- p50 server response time in the same provider-run MMLU-Pro test
The limit
These measurements were designed and run by Celeris, not an independent lab, and they do not rank every workload. Speed changes with the prompt, output length, region, and network. Retain a slower, more capable model for very long-form generation or extended multi-step reasoning. Test a labeled fixture at each node and keep a fallback.
Where it earns a trial
Route to a fixed label
Reject any output outside the allowed tool or intent set.
Extract a fixed schema
Ask for JSON, then validate types and required fields before the next step runs.
Score a bounded decision
Calibrate the result against human-labeled cases instead of trusting fluent reasons.
Rewrite a retrieval query
Preserve names, dates, and constraints, then judge the retrieved result rather than the query’s prose.
The swap is deliberately small
Compatible request shape
The API supports OpenAI-compatible chat completions and Responses at https://inference.celeris.ai/celeris-1/v1.
Current limits and pricing
The model documentation sets an 8,192-token total for prompt plus requested output. Pricing is $2 per million prompt tokens and $6 per million completion tokens.
Decision note
Put Celeris-1 on one repeated, checkable call boundary. If the task still passes and the trace gets shorter, keep it there.
Partner links
The links below lead to Celeris and are part of the sponsored edition.