Deep Cogito: Cogito v2.1 671B

POST/v1/chat/completions

Cogito v2.1 671B MoE represents one of the strongest open models globally, matching performance of frontier closed and open models. This model is trained using self play with reinforcement learning to reach state-of-the-art performance on multiple categories (instruction following, coding, longer queries and creative writing). This advanced system demonstrates significant progress toward scalable superintelligence through policy improvement.

Request body

Parameters supported by this model. Values, defaults, and limits are read from the model registry.

stringmodelrequired

Model identifier. Set to deepcogito/cogito-v2.1-671b.

Default: deepcogito/cogito-v2.1-671b

array<object>messagesrequired

Conversation messages in system, user, or assistant order.

Optional<integer>max_tokens

Maximum number of tokens the model may generate in the response.

Range: −∞ to 128000

Optional<number>temperature

Sampling temperature. Lower values are more deterministic; higher values are more creative.

Range: 0 to 2

Default: 1

Optional<number>top_p

Nucleus sampling threshold. Use this or temperature, but usually not both.

Range: 0 to 1

Optional<boolean>stream

When true, returns incremental Server-Sent Events instead of one completed response.

Default: false

Optional<object>response_format

Controls the response format, including JSON mode or structured JSON output when supported.

Optional<array<string>>stop

Sequences that stop generation when the model produces one of them.

Optional<number>presence_penalty

Penalizes tokens that already appeared, encouraging the model to introduce new topics.

Range: -2 to 2

Optional<number>frequency_penalty

Penalizes repeated tokens, reducing repetition in the generated response.

Range: -2 to 2

Optional<integer>top_k

Request parameter supported by this model.

Range: 0 to ∞

Response Schema

Fields returned by this model API response.

array<object>choicesrequired

Generated completion choices.

stringidrequired

Unique chat completion identifier.

stringmodelrequired

Model that generated the response.

Optional<object>usage

Token usage when available.

Model capabilities

array<string>capability_tagsrequired

Capabilities declared by the model registry.

Default: chat, reasoning, structured_output

integercontext_lengthrequired

Maximum context window accepted by this model.

Default: 128000 tokens

stringexecution_moderequired

Execution mode declared by the model registry.

Default: sync

curl -X POST https://api.sandbase.ai/v1/chat/completions \
  -H "Authorization: Bearer $SANDBASE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "deepcogito/cogito-v2.1-671b",
  "messages": [
    {
      "role": "user",
      "content": "Describe this product in one sentence."
    }
  ]
}'

Response200 OK

{
  "id": "chatcmpl_abc123",
  "model": "deepcogito/cogito-v2.1-671b",
  "choices": [
    {
      "message": {
        "role": "assistant",
        "content": "A concise product description."
      }
    }
  ]
}