GPT-5.5
GPT-5.5 is OpenAI's newest frontier model for complex professional work, with strong performance in coding, reasoning, and tool-using workflows. It supports a 1,050,000 token context window, 128,000 max output tokens, configurable reasoning effort, image input, and a broad tool stack including web search, file search, code interpreter, hosted shell, apply patch, skills, MCP, tool search, and computer use.
Complete technical specification for integration
API Options
Platform-level options for task execution and delivery.
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taskType
string required value: textInference -
Identifier for the type of task being performed
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taskUUID
string required UUID v4 -
UUID v4 identifier for tracking tasks and matching async responses. Must be unique per task.
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outputFormat
string default: TEXT -
Specifies the file format of the generated output. The available values depend on the task type and the specific model's capabilities.
Allowed values 2 values
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webhookURL
string URI -
Specifies a webhook URL where JSON responses will be sent via HTTP POST when generation tasks complete. For batch requests with multiple results, each completed item triggers a separate webhook call as it becomes available.
Learn more 1 resource
- Webhooks PLATFORM
- Webhooks
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deliveryMethod
string default: sync -
Determines how the API delivers task results.
Allowed values 3 values
- Returns complete results directly in the API response.
- Returns an immediate acknowledgment with the task UUID. Poll for results using getResponse.
- Streams results token-by-token as they are generated.
Learn more 1 resource
- Task Polling PLATFORM
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includeCost
boolean default: false -
Include task cost in the response.
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includeUsage
boolean default: false -
Include token usage statistics in the response.
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numberResults
integer min: 1 max: 4 default: 1 -
Number of results to generate. Each result uses a different seed, producing variations of the same parameters.
Inputs
Input resources for the task (images, audio, etc). These must be nested inside the inputs object.
inputs object.-
inputs»imagesimages
array of strings min items: 1 -
Array of image inputs (UUID, URL, Data URI, or Base64).
Generation Parameters
Core parameters for controlling the generated content.
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model
string required value: openai-gpt-5-5 -
Identifier of the model to use for generation.
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jsonSchema
object | string -
JSON Schema for structured output. Only honoured when
outputFormatis JSON. Accepts the OpenAI envelope ({name, schema, strict}) or a bare JSON Schema; bare schemas are auto-wrapped withname='response'andstrict=true.
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messages
array of objects required min items: 1 -
Array of chat messages forming the conversation context.
Settings
Technical parameters to fine-tune the inference process. These must be nested inside the settings object.
settings object.-
settings»systemPromptsystemPrompt
string min: 1 max: 200000 -
System-level instruction that guides the model's behavior and output style across the entire generation.
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settings»maxTokensmaxTokens
integer min: 1 max: 128000 default: 4096 -
Maximum number of tokens to generate in the response.
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settings»thinkingLevelthinkingLevel
string default: medium -
Controls the depth of internal reasoning the model performs before generating a response.
Allowed values 5 values
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toolChoice
object -
Controls how the model selects which tool to call. This only takes effect when
toolsare defined.Examples 3 examples
Let the model decide (default):
"toolChoice": { "type": "auto" }Force a specific tool call:
"toolChoice": { "type": "tool", "name": "get_weather" }Require any tool call:
"toolChoice": { "type": "any" }Properties 2 properties
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toolChoice»typetype
string required -
Strategy the model uses to decide when and which tools to call.
Allowed values 4 values
- The model decides whether to call a tool based on the conversation context. This is the recommended default.
- The model must call at least one tool but chooses which one. Useful when you always need structured output.
- The model must call the specific tool identified by
name. Use this to force a particular function call. - The model will not call any tool, even if tools are defined. Useful for forcing a text-only response.
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toolChoice»namename
string -
Name of the specific tool the model must call. Required when type is
tool.
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tools
array of objects min items: 1 -
An array of tool definitions that the model may call during generation. The model can invoke one or more tools based on the conversation context, outputting structured calls with arguments instead of (or alongside) free-text.
For
functiontools, each definition requires:type:"function"name: Unique identifier (alphanumeric, hyphens, underscores; max 64 chars).description: What the function does. The model uses this to decide when to call it.schema: JSON Schema object describing the expected input arguments.
The
searchtool is executed server-side by the provider. You don't need to handle the tool result yourself.The
codeInterpretertool is executed server-side by the provider. You don't need to handle the tool result yourself.Examples 4 examples
Function tool, weather lookup:Built-in web search:"tools": [ { "type": "function", "name": "get_weather", "description": "Get current weather for a city", "schema": { "type": "object", "properties": { "city": { "type": "string", "description": "City name" } }, "required": ["city"] } } ], "toolChoice": { "type": "auto" }Built-in code interpreter:"tools": [ { "type": "search" } ]Multiple function tools:"tools": [ { "type": "codeInterpreter" } ]"tools": [ { "type": "function", "name": "search_products", "description": "Search the product catalog by query and filters.", "schema": { "type": "object", "properties": { "query": { "type": "string" }, "category": { "type": "string" } }, "required": ["query"] } }, { "type": "function", "name": "add_to_cart", "description": "Add a product to the user's shopping cart.", "schema": { "type": "object", "properties": { "productId": { "type": "string" }, "quantity": { "type": "integer", "minimum": 1 } }, "required": ["productId"] } } ]Properties 4 properties
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tools»typetype
string required -
The kind of tool to make available to the model. User-defined functions require
nameandschema, while built-in tools (search,codeInterpreter) are executed server-side by the provider.Allowed values 3 values
- User-defined function tool. The model outputs the tool name and arguments. You execute the function locally and send results back.
- Built-in web search. The provider executes search server-side and enriches the response automatically.
- Built-in code execution sandbox (Python). The provider runs code server-side and returns results automatically.
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tools»namename
string max: 64 -
Unique function name. Required for function tools.
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tools»descriptiondescription
string -
Explanation of what the function does, used by the model to decide when to call it.
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tools»schemaschema
object -
JSON Schema object describing the function's input parameters.