Repository of case law files
AI Models & Assistants / Knowledge library
GPT-5.5 Pro
Version of GPT-5.5 that produces smarter and more precise responses.
Why learn GPT-5.5 Pro?
Offers the documented OpenAI model capabilities through hosted.
The problem it solves
Provides model inference for supported text / image inputs.
Where it came from
GPT-5.5 Pro: Version of GPT-5.5 that produces smarter and more precise responses. Published aliases: gpt-5.5-pro-2026-04-23. Input: text, image. Output: text. Checked 2026-10-13. Model capabilities are distinct from tools available in a particular agent.
Build your understanding
Work through these exercises in order. Try the task before opening a reference.
- Explain what GPT-5.5 Pro does.
- Identify a use case for GPT-5.5 Pro.
- Describe a limitation of GPT-5.5 Pro.
- Name a compatible tool for GPT-5.5 Pro.
- Compare GPT-5.5 Pro against an alternative.
Documentation and sources
- Primary source / model card (developers.openai.com)
Catalog research notes
- See the AI Workbench for source dates, pricing evidence and configuration details.
Connect the ideas
Built on
Real World Example
Automated Legal Precedent Synthesis
Large-scale international law firms managing complex cross-border litigation.
The business problem
Standard models frequently hallucinate or fail to synthesize nuanced contradictions across thousands of pages of multi-jurisdictional case law, leading to high manual review costs and risk of oversight.
How this topic solves it
GPT-5.5 Pro leverages high-compute reasoning capabilities via the Responses API to perform deep cross-referencing of legal documents, ensuring logical consistency and precision in synthesis.
- Ingest multi-jurisdictional case files into the file_search tool environment.
- Configure the Responses API request with reasoning.effort set to xhigh to maximize analytical depth.
- Submit the synthesis task using background mode to accommodate the extended processing time required for complex legal reasoning.
- Retrieve the structured output containing validated legal arguments and cited precedents.
The flow of data from ingestion to final synthesis using the Responses API.
Interface for gpt-5.5-pro
Asynchronous processing
Final legal brief
- Document Store → file_search input → Responses API
- Responses API → triggers background mode → Background Job
- Background Job → delivers result → Synthesis Output
Implementation example
This code demonstrates initiating a high-effort synthesis task using the Responses API in background mode, which is essential for handling the complex reasoning required for legal analysis.
client.responses.create(
model='gpt-5.5-pro-2026-04-23',
input='Synthesize the legal conflict between these files.',
reasoning_effort='xhigh', # Maximize analytical depth
mode='background' # Prevent timeouts for long tasks
)Expected business outcome
Improved accuracy in legal brief drafting with significantly reduced manual verification requirements for cross-jurisdictional consistency.
Limitations and checks
The high-compute nature of the model results in longer request latency; developers must monitor background job status to check for completion.