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gpt-5.6-sol

Quality-first tier in the GPT-5.6 preview family for demanding reasoning, multi-tool agents, and high-value production work.

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Overview

GPT-5.6 Sol is the quality-first tier in the GPT-5.6 preview family represented in the current GPT88 catalog.
It is intended for complex reasoning, long-running agents, difficult software work, and research tasks where output quality matters more than minimum latency or cost.
This page summarizes the current catalog positioning without treating third-party commentary as an official capability, availability, or pricing commitment.

Best Use Cases

Choose it when quality and task-completion reliability matter more than the lowest latency or cost
Evaluate it for multi-step planning, large codebases, long-document research, or multi-tool agent work
Use it to test GPT-5.6 preview behavior in an existing OpenAI-compatible SDK, Cursor, Codex CLI, or internal agent
Start with a small set of high-value tasks to measure the upper end of the GPT-5.6 family

Integration Notes

Use the GPT88 Base URL https://api.gpt88.cc and set model to gpt-5.6-sol in OpenAI-compatible requests.
Call GET /v1/models or check the console before sending traffic, because model access can differ by API key and route.
Compare Sol, Terra, GPT-5.5, and GPT-5.4 on the same representative evaluation set before changing a default model.
For agent workflows, validate a minimal non-streaming request first, then add streaming, tools, structured output, and multi-turn context one feature at a time.

Usage Notes

Availability, pricing, context limits, rate limits, routes, vision support, and tool support are determined by the current GPT88 console configuration.
GPT-5.6 Sol is a preview model. Behavior, availability, and supported parameters may change, so use a staged rollout instead of replacing every production default at once.
For frequent short requests such as classification, summaries, and routing, compare Terra, Luna, or a mini-tier model before choosing Sol.
Validate quality, latency, failure modes, and usage on your own workload before expanding production traffic.

Capabilities

GPT-5.6 previewComplex reasoningTool useMultimodal workflows

Recommended Scenarios

Advanced agent workflows
Complex software engineering
Research and analysis
Long-running automation

Endpoint Path

POSThttps://api.gpt88.cc/v1/chat/completions

The endpoint path is determined by the model category. Chat, image, video, and audio models use different endpoints.

Send requests with Authorization: Bearer <API_KEY>. See Chat Completions API for the full parameter reference.

API Docs

Endpoint

POST /v1/chat/completions

Model ID

gpt-5.6-sol

Content-Type

application/json

Protocol

OpenAI-compatible chat completions endpoint with streaming and non-streaming output.

Base URL

Use https://api.gpt88.cc for OpenAI SDK, Cursor, and cURL.

Headers / Auth

Field	Type	Required	Description
`Authorization`	string	Required	Send `Bearer <GPT88_API_KEY>`. Create the API key in the gpt88.cc console.
`Content-Type`	string	Required	Request body format. Audio transcription uploads use `multipart/form-data`. Default:`application/json`
`Accept`	string	Optional	Non-streaming requests return JSON; streaming chat requests return SSE chunks. Default:`application/json or text/event-stream`

AuthorizationstringRequired
Send Bearer <GPT88_API_KEY>. Create the API key in the gpt88.cc console.
Content-TypestringRequired
Request body format. Audio transcription uploads use multipart/form-data.
Default:application/json
Acceptstring
Non-streaming requests return JSON; streaming chat requests return SSE chunks.
Default:application/json or text/event-stream

Chat Protocol Differences

For chat models, the protocol used by the client matters as much as the model name. Claude Code / Anthropic SDK and OpenAI SDK build different request paths.

OpenAI CompatibleRecommended

Base URL: https://api.gpt88.cc
Endpoint: POST /v1/chat/completions
Body: { "model": "gpt-5.6-sol", "messages": [...] }

Anthropic / Claude

Base URL: https://api.gpt88.cc
Endpoint: POST /v1/messages
Body: { "model": "gpt-5.6-sol", "messages": [...] }

This model is usually best accessed through the OpenAI-compatible protocol. Only use the Anthropic-style path when the target tool explicitly requires it.

Request Parameters

The fields below are generated by model category. Pricing, context limits, rate limits, and available routes should be confirmed in the gpt88.cc console.

Field	Type	Required	Description
`model`	string	Required	Current model ID: `gpt-5.6-sol`. Preserve the exact casing when copying.
`messages`	array<Message>	Required	Conversation history. Each message includes `role` and `content`.
`stream`	boolean	Optional	Enable SSE streaming. Useful for chat interfaces and long responses. Default:`false`
`temperature`	number	Optional	Sampling temperature. Higher values produce more variation; production workloads usually start with a fixed value. Default:`1`
`max_tokens`	integer	Optional	Maximum output tokens for this request. Real context limits should be confirmed in the console.
`response_format`	object	Optional	Structured output config, for example `{ "type": "json_object" }`.
`tools`	array<Tool>	Optional	Function-calling tool definitions. Availability depends on the model and account configuration.

modelstringRequired
Current model ID: gpt-5.6-sol. Preserve the exact casing when copying.
messagesarray<Message>Required
Conversation history. Each message includes role and content.
streamboolean
Enable SSE streaming. Useful for chat interfaces and long responses.
Default:false
temperaturenumber
Sampling temperature. Higher values produce more variation; production workloads usually start with a fixed value.
Default:1
max_tokensinteger
Maximum output tokens for this request. Real context limits should be confirmed in the console.
response_formatobject
Structured output config, for example { "type": "json_object" }.
toolsarray<Tool>
Function-calling tool definitions. Availability depends on the model and account configuration.

Response Fields

Response bodies generally follow OpenAI-compatible shapes. Media models may return async task IDs or resource URLs.

Field	Type	Required	Description
`id`	string	Required	Unique completion ID for tracing and debugging.
`object`	string	Required	Usually `chat.completion` or a streaming chunk type.
`model`	string	Required	Actual model ID that handled inference.
`choices`	array<Choice>	Required	Generated choices including `message`, `delta`, and `finish_reason`.
`usage`	object	Optional	Token usage statistics. Streaming calls may return this only at the end or in non-streaming mode.

idstringRequired
Unique completion ID for tracing and debugging.
objectstringRequired
Usually chat.completion or a streaming chunk type.
modelstringRequired
Actual model ID that handled inference.
choicesarray<Choice>Required
Generated choices including message, delta, and finish_reason.
usageobject
Token usage statistics. Streaming calls may return this only at the end or in non-streaming mode.

Status Codes

Field	Type	Required	Description
`200`	OK	Required	Request succeeded. See the response field table above for the response body shape.
`400`	Bad Request	Optional	Invalid request fields, such as missing required fields, unsupported image size format, or unsupported file type.
`401`	Unauthorized	Optional	API key is missing, invalid, or malformed.
`404`	Not Found	Optional	Endpoint or model not found. Confirm the path is `/v1/chat/completions` and the model ID is `gpt-5.6-sol`.
`429`	Rate Limited	Optional	Rate limit, concurrency cap, or insufficient balance. Check the console for the current allowance.
`5xx`	Upstream Error	Optional	Upstream or request failure. Retry with the same Base URL and keep the request ID for debugging.

200OKRequired
Request succeeded. See the response field table above for the response body shape.
400Bad Request
Invalid request fields, such as missing required fields, unsupported image size format, or unsupported file type.
401Unauthorized
API key is missing, invalid, or malformed.
404Not Found
Endpoint or model not found. Confirm the path is /v1/chat/completions and the model ID is gpt-5.6-sol.
429Rate Limited
Rate limit, concurrency cap, or insufficient balance. Check the console for the current allowance.
5xxUpstream Error
Upstream or request failure. Retry with the same Base URL and keep the request ID for debugging.

Errors and Troubleshooting

401: verify Authorization is Bearer <API_KEY> and the key is still valid.
404: confirm the endpoint is /v1/chat/completions and the model ID gpt-5.6-sol is available in the console.
429: reduce concurrency, shorten requests, or check balance and quota in the console.
5xx: retry with the same Base URL and keep the request ID for debugging.

Request Examples

curl https://api.gpt88.cc/v1/chat/completions \
  -H "Authorization: Bearer $GPT88_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-5.6-sol",
    "messages": [
      {"role": "user", "content": "Introduce gpt88.cc in one sentence."}
    ]
  }'

Expected response (trimmed example):

200 OKjson

{
  "id": "chatcmpl-gpt-5-6-",
  "object": "chat.completion",
  "created": 1730000000,
  "model": "gpt-5.6-sol",
  "choices": [
    {
      "index": 0,
      "finish_reason": "stop",
      "message": { "role": "assistant", "content": "..." }
    }
  ],
  "usage": { "prompt_tokens": 24, "completion_tokens": 64, "total_tokens": 88 }
}