Compare

POST /v1/chat/compare runs one prompt across multiple models concurrently. See Compare for the full guide.

Some models are missing from the result (partial: true)

Model calls are isolated — if one fails or hits the 120s hard timeout, the others continue and the response carries partial: true. Check each result’s error / error_code; a partial response is expected behavior, not a failure of the whole call.

Too many / duplicate models

models accepts 1–10 entries. Duplicates are removed automatically, so listing the same model twice won’t run it twice.

Billing is higher than expected

Compare bills N+1 usage events: one per fan-out model plus the synthesis/comparison call. (For rate limits, though, the whole comparison counts as a single request against RPM/RPD.) Set skip_comparison: true to drop the comparison call if you only need raw outputs.

Streaming behaves differently than chat

There are two modes:

• With comparison (default) — fan-out models are non-streaming; only the final comparison text streams token-by-token (comparison_chunk).
• skip_comparison: true — each model streams concurrently, tagged by model name (model_chunk / model_stream_done).

Watch for comparison_fallback_used in the done event if the comparison model had to fall back.

Still stuck?

See the Mesh API error reference or email contact@meshapi.ai.