OpenAI: GPT-5.6 Sol

openai/gpt-5.6-sol

GPT-5.6 Sol is the flagship model in OpenAI's GPT-5.6 series. It is suited for complex reasoning, coding, and agentic workflows, and is particularly strong at command-line and multi-step coding tasks...

visiontools
MODALITIES
INPUT PRICE
$0.30per 1M
OUTPUT PRICE
$3per 1M
CONTEXT
1.05M
RELEASED
Jul 9, 2026
ProviderCacheUptimeChat
5.00(1)$0.3$3
Hit rate96.8%
Cache read$0.03

Capabilities

Input modalities
fileimagetext
Output modalities
text
Features
include_reasoningmax_completion_tokensmax_tokensreasoningreasoning_effortresponse_formatseedstructured_outputstool_choicetools
1

Get your API key

Create an API key from the Keys page, then set it as an environment variable:

export ONLIST_API_KEY=sk-...
2

Make your first request

Endpoints

POSThttps://onlist.io/v1/chat/completions

OpenAI Chat Completions format

Request Headers
Authorization:Bearer $ONLIST_API_KEY
Content-Type:application/json
Model:openai/gpt-5.6-sol
POSThttps://onlist.io/v1/responses

OpenAI Responses format

Request Headers
Authorization:Bearer $ONLIST_API_KEY
Content-Type:application/json
Model:openai/gpt-5.6-sol
POSThttps://onlist.io/v1/messages

Anthropic Messages format

Request Headers
Authorization:Bearer $ONLIST_API_KEY
Content-Type:application/json
Model:openai/gpt-5.6-sol

Code samples

curl https://onlist.io/v1/chat/completions \
  -H "Authorization: Bearer $ONLIST_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
       "model": "openai/gpt-5.6-sol",
       "messages": [
         {
           "role": "user",
           "content": "Explain quantum entanglement in one paragraph."
         }
       ]
     }'

Replace $ONLIST_API_KEY with the API key from your Keys page.

Authentication

All requests must include an Authorization: Bearer <TOKEN> header. Generate keys from the Keys page; keys can be scoped to specific models, groups, IP ranges, and rate limits.

3

Enable streaming

Add "stream": true to receive partial responses as server-sent events in real time.

Streaming example

curl https://onlist.io/v1/chat/completions \
  -H "Authorization: Bearer $ONLIST_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
       "model": "openai/gpt-5.6-sol",
       "messages": [
         {
           "role": "user",
           "content": "Write a haiku about recursion."
         }
       ],
       "stream": true
     }'

Supported parameters

NameTypeDescription
include_reasoning
max_completion_tokensintegerUpper bound on tokens generated, including visible and reasoning tokens.
max_tokensintegerMaximum number of tokens to generate in the completion.
reasoning
reasoning_effortstringConstrains effort on reasoning. Supported values: "low", "medium", "high".
response_formatobjectSpecifies the output format. Use {"type": "json_object"} for JSON mode.
seedintegerIf specified, the system will attempt deterministic sampling for reproducible results.
structured_outputs
tool_choicestring | objectControls which tool is called. "auto", "none", "required", or a specific function.
toolsarrayA list of tools the model may call. Currently supports functions.

These are the request parameters this model accepts. Parameter semantics follow the OpenAI Chat Completions specification.