AI Prompts for Gemini for Code Documentation
20 of the best prompts for Gemini for code documentation, step by step across 4 stages. Works with ChatGPT, Claude, and Gemini.
AI Prompts for Gemini for Code Documentation
20 of the best prompts for Gemini for code documentation, step by step across 4 stages. Works with ChatGPT, Claude, and Gemini.
Published July 9, 2026
Most people try to use AI for Gemini for Code Documentation with a single vague prompt and get generic results. This guide takes a different approach: 4 targeted stages, from Inline Comments and Docstrings through Architecture and Technical Docs, each with a prompt that gives the AI exactly the context it needs. Write clear, complete code documentation using Gemini to generate inline comments, docstrings, READMEs, and API references. Works with ChatGPT, Claude, and Gemini.
Inline Comments and Docstrings
Use Gemini to add documentation that explains the non-obvious logic and purpose behind your code.
Write docstring
Write a docstring for this function: [PASTE FUNCTION]. Include: description, parameters (name, type, description), return value, and one example. Use [LANGUAGE/FORMAT] conventions.
Add inline comments
Add inline comments to this complex code to explain the non-obvious logic: [PASTE CODE]. Focus on the why, not the what.
Generate docstrings
Generate docstrings for all public functions in this file: [PASTE FILE]. Use [JSDOC / GOOGLE / NUMPY] style consistently.
Code has no
This code has no documentation and is hard to follow. Add the minimum comments needed to make it accessible to a developer seeing it for the first time: [PASTE CODE].
Write comment block explaining
Write a comment block explaining this algorithm: [PASTE CODE]. Include: the problem it solves, the approach, time complexity, and any important assumptions or constraints.
README and Project Documentation
Use Gemini to write project-level documentation that helps developers get started fast.
Write README
Write a README for this project: [DESCRIBE PROJECT AND STACK]. Include: description, installation, configuration, usage examples, and contributing guidelines.
Write Getting Started guide
Write a Getting Started guide for [PROJECT]. Target a developer who knows [LANGUAGE] but has never used this project. Cover: setup, configuration, and first working example.
Improve README:
Improve this README: [PASTE README]. Clarify the project purpose, make the examples runnable, and reorganize so the most important information is immediately findable.
Write CONTRIBUTING.md
Write a CONTRIBUTING.md for [PROJECT] covering: dev environment setup, coding standards, how to run tests, and the PR process.
Write CHANGELOG entry
Write a CHANGELOG entry for this release: [DESCRIBE CHANGES]. Use Keep a Changelog format with sections for Added, Changed, Fixed, and Removed.
API Documentation
Use Gemini to write API documentation that makes integration fast and error-free.
Document API endpoint:
Document this API endpoint: [PASTE HANDLER CODE]. Include: method, path, description, request parameters, response schema, and example request/response.
Generate OpenAPI 3.0 YAML
Generate an OpenAPI 3.0 YAML spec for these endpoints: [PASTE ROUTES AND SCHEMAS]. Include all paths, request bodies, responses, and auth requirements.
Write developer-facing SDK documentation
Write developer-facing SDK documentation for this function: [PASTE FUNCTION]. Focus on how to use it, what it returns, and common patterns.
Document error codes
Document the error codes for this API: [PASTE ERROR HANDLING CODE]. For each: code, HTTP status, description, and developer action.
Write authentication guide
Write an authentication guide for this API: [PASTE AUTH CODE]. Include: the method, how to get credentials, token lifecycle, and a working example in [LANGUAGE].
Architecture and Technical Docs
Use Gemini to document system design and operational procedures.
Write architecture overview
Write an architecture overview for this system: [DESCRIBE COMPONENTS AND INTERACTIONS]. Include: component descriptions, data flow, and key design decisions.
Write Architecture Decision Record
Write an Architecture Decision Record for this decision: [DESCRIBE DECISION]. Include: context, options considered, decision made, rationale, and consequences.
Document data model
Document the data model for this schema: [PASTE SCHEMA]. For each entity: purpose, key fields, relationships, and important constraints.
Write runbook
Write a runbook for this operation: [DESCRIBE OPERATION]. Include: prerequisites, step-by-step instructions, verification steps, and rollback procedure.
Write troubleshooting guide
Write a troubleshooting guide for the most common issues with [SERVICE]. For each issue: symptoms, diagnostic steps, root causes, and resolution.
Frequently asked questions
Is Gemini good at writing code documentation?+
Yes. Gemini reads code structure accurately and produces documentation that matches the actual implementation. It handles docstrings, READMEs, API docs, and architecture documents. For large files, work section by section for the best output quality.
What documentation formats does Gemini support?+
Gemini handles JSDoc, Python docstrings (Google, NumPy, reStructuredText), JavaDoc, OpenAPI/Swagger, Markdown READMEs, and prose documentation. Specify the format in your prompt.
How do I document a large codebase with Gemini?+
Prioritize public APIs and complex internal functions. Work file by file. Ask Gemini to document all functions in one file before moving to the next. Start where documentation provides the most value to maintainers.
Will Gemini docstrings be accurate?+
Yes, based on what the code actually does. Gemini reads the implementation and documents accordingly. Review docstrings for functions with non-obvious side effects or dependencies on external context that Gemini cannot see.
Can Gemini write README files that help developers get started?+
Yes. Provide the project description, tech stack, and target audience. Gemini generates a structured README covering installation, usage, and contribution. Add your specific installation commands and real examples before publishing.
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