Custom GPT Developer for Document Review and Compliance Workflow

We are seeking an experienced Custom GPT developer to design, build, test, and refine a GPT-based document review system. First Project The goal is to create a reliable GPT that can review uploaded documents against a detailed style guide or rule set, identify deviations, and produce a clear, structured exceptions report. This project requires more than basic prompt writing. The ideal candidate should understand Custom GPT configuration, advanced instruction design, document-processing workflows, API integrations, and systematic testing. Scope of Work The selected freelancer will: Build and configure a Custom GPT in ChatGPT Design robust system instructions and review workflows Configure knowledge files and reference materials Create structured, consistent output formats Develop logic for checking repeated elements and rule compliance Reduce hallucinations, missed issues, and false positives Identify which requirements can be handled directly in a Custom GPT and which may require an external service Integrate external tools or APIs when necessary Create a testing and evaluation process Test the GPT against documents containing known errors Refine the GPT based on test results Document the final setup, limitations, and maintenance process Required Skills Demonstrated experience building Custom GPTs Advanced prompt and instruction design OpenAI API experience GPT Actions and OpenAPI schema experience Python or Node.js REST APIs, JSON, and authentication Document-processing automation Microsoft Word .docx processing python-docx, OOXML, Open XML, or similar technologies Experience inspecting styles, direct formatting, tables, headers, footers, fields, and document structure Experience with document rendering or visual page inspection Structured Outputs or JSON Schema LLM testing, evaluations, and regression testing Error handling, logging, and secure file processing Preferred Qualifications Experience building document-review, quality-control, legal-review, or compliance-review systems Experience comparing documents against detailed rulebooks or style guides Experience creating automated test sets with intentionally planted errors Experience measuring false positives and false negatives Familiarity with Microsoft Graph, Office Scripts, or Word automation Experience deploying lightweight Python or Node.js backend services Strong written communication and technical documentation skills