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...
| Provider | Cache | Uptime | Chat | |||
|---|---|---|---|---|---|---|
| 5.00(1) | $0.3 | $3 | Hit rate96.8% Cache read$0.03 |
Capabilities
Get your API key
Create an API key from the Keys page, then set it as an environment variable:
export ONLIST_API_KEY=sk-...Make your first request
Endpoints
https://onlist.io/v1/chat/completionsOpenAI Chat Completions format
https://onlist.io/v1/responsesOpenAI Responses format
https://onlist.io/v1/messagesAnthropic Messages format
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.
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
| Name | Type | Description |
|---|---|---|
include_reasoning | ||
max_completion_tokens | integer | Upper bound on tokens generated, including visible and reasoning tokens. |
max_tokens | integer | Maximum number of tokens to generate in the completion. |
reasoning | ||
reasoning_effort | string | Constrains effort on reasoning. Supported values: "low", "medium", "high". |
response_format | object | Specifies the output format. Use {"type": "json_object"} for JSON mode. |
seed | integer | If specified, the system will attempt deterministic sampling for reproducible results. |
structured_outputs | ||
tool_choice | string | object | Controls which tool is called. "auto", "none", "required", or a specific function. |
tools | array | A 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.