The Art of the Ask: A Compendium of Advanced Codex Prompt Examples Unlocking the Full Potential of Your AI Engineering Partner – June 2025

Interacting with OpenAI Codex, especially its highly evolved June 2025 iteration, is less about giving simple commands and more akin to briefing a highly skilled, albeit artificial, engineering colleague. The quality of your "ask"—the prompt—is paramount. Effective prompt engineering is the bridge between human intent and an AI's vast capabilities, transforming Codex from a powerful tool into a truly indispensable partner. This page delves into the art and science of crafting such prompts, offering practical, real-world examples complete with the scenarios they address and the sophisticated outcomes you can expect. These examples reflect Codex's advanced understanding of entire repositories, its capacity for multi-step reasoning, and its ability to engage in complex software engineering tasks.

Foundational Principles of Effective Codex Prompting

Before diving into specific examples, it's crucial to internalize a few core principles that underpin successful interactions with Codex. While a comprehensive guide can be found on our How to Use Codex page, these tenets are worth reiterating:

  • Be Explicit & Unambiguous: Clearly define your goal, the context, and any constraints. The more specific your instructions, the more targeted and accurate Codex's response will be.
  • Context is Sovereign: Provide as much relevant context as possible. This includes file names, specific functions or classes, error messages, relevant snippets of existing code, project structure overviews, and even desired coding styles or patterns. For the June 2025 Codex, you can often point it to the entire repository.
  • Embrace Iteration: Prompting is often a dialogue, not a monologue. Be prepared to refine your prompts based on Codex's initial outputs, ask follow-up questions, or provide clarifications.
  • Define Scope Clearly: Specify what Codex *should* do and, equally importantly, what it *should not* touch or alter. This is crucial for preventing unintended side effects in complex operations.
  • Set Realistic Expectations: While incredibly powerful, Codex is an assistant. Human oversight, critical review, and thorough testing of its outputs remain indispensable components of responsible AI-assisted development.

Advanced Prompt Engineering: Scenarios & Outcomes

The following examples illustrate how to leverage the advanced capabilities of the June 2025 version of Codex for a variety of common and complex software engineering tasks. Each example provides the prompt, a detailed scenario, and an explanation of the typical interaction and outcome.

1. Debugging: Automated Error Resolution

The Prompt:

In my Python Flask application, I'm getting a 'KeyError: "user_id"' in `app/routes.py` within the `get_user_profile` function specifically when a new user who hasn't completed onboarding tries to access their profile. Scan `app/models.py` for the User model structure and `app/auth.py` for the session handling. Identify the root cause and apply a fix to `routes.py` that gracefully handles this case by redirecting to the onboarding page (`/onboard`) if `user_id` is missing or the profile is incomplete. Ensure the fix includes appropriate logging for this event.

Scenario Deep Dive:

A developer is working on a web application and has encountered a runtime error reported by users. The error only occurs for a specific subset of users (new, unonboarded ones) under particular conditions, making it tricky to reproduce consistently without understanding the exact state. Manually tracing the error through multiple files (routes, models, authentication logic) can be time-consuming. The goal is not just to prevent the crash but to implement a user-friendly redirect and ensure the event is logged for monitoring.

Codex in Action: Typical Outcome & Interaction

The June 2025 Codex, with its repository-wide understanding, would first parse the specified files (`routes.py`, `models.py`, `auth.py`). It would analyze the `get_user_profile` function, the `User` model structure (looking for fields that indicate profile completeness or onboarding status), and how user sessions or `user_id` are managed in the auth logic.

Codex would likely identify that the `KeyError` arises from attempting to access a dictionary key or session variable that hasn't been set for users in that specific state. It might then propose a change to `routes.py` similar to:
  • Adding a check at the beginning of `get_user_profile` to see if `user_id` is in the session or if a related user profile field (e.g., `is_onboarded`) is false.
  • If the condition is met, it would insert a `redirect(url_for('onboard'))` call (assuming Flask's `url_for` and a route named 'onboard').
  • It would also add a logging statement (e.g., `current_app.logger.info('User redirected to onboarding due to incomplete profile.')`) before the redirect.
Codex might present the exact code changes as a diff and explain its reasoning. It might also ask for clarification if the "profile completeness" logic is ambiguous across the provided files.
Benefits: Rapid root cause analysis and fix implementation, consistent error handling, and automated logging, saving significant debugging time.

2. Documentation: Comprehensive Docstring Generation

The Prompt:

Analyze all public functions and classes within the 'src/core/utils/' directory of my project. For each, generate comprehensive docstrings following the Google Python Style Guide. Ensure each docstring includes:
1. A concise summary of the function/class purpose.
2. Detailed descriptions for all arguments/parameters, including their expected types.
3. A clear description of the return value and its type.
4. Any exceptions that the function/class might explicitly raise, along with conditions for raising them.
Update the files in place.

Scenario Deep Dive:

A development team is working to improve the maintainability and understandability of a critical utility module. The module has several public functions and classes that lack proper documentation. Manually writing detailed docstrings for each, adhering strictly to a specific style guide (like Google's), is a tedious and error-prone task, especially across many files. The goal is to automate this process to ensure consistency and completeness.

Codex in Action: Typical Outcome & Interaction

Codex would first scan all Python files in the specified directory. For each public function and class, it would analyze its signature (parameters, name) and, importantly, attempt to infer its behavior and purpose by examining its internal logic and how it's used elsewhere in the codebase (if that context is available or if Codex has indexed the repo).

It would then generate docstrings formatted according to the Google Python Style Guide. For a function like `def calculate_mean(numbers: list[float]) -> float:`, it might produce: ```python """Calculates the arithmetic mean of a list of numbers. Args: numbers (list[float]): A list of floating-point numbers. An empty list will raise a ValueError. Returns: float: The arithmetic mean of the numbers in the list. Raises: ValueError: If the input list 'numbers' is empty. """ ``` Codex would systematically go through each item, inferring types if not explicitly hinted (though type hints in the original code greatly improve accuracy) and attempting to identify common exceptions like `ValueError` or `TypeError` based on internal checks. It would then present the modified files or a diff for review before changes are committed.
Benefits: Saves massive amounts of developer time, ensures consistent documentation style, improves code readability and maintainability, and facilitates easier onboarding for new team members.

3. Refactoring: Large-Scale Framework & Language Migration

The Prompt:

This project is a monolithic Django 2.2 application running on Python 3.7. I need to migrate it to Django 4.2 and Python 3.11.
Tasks:
1. Analyze `requirements.txt` and update all dependencies to versions compatible with Django 4.2/Python 3.11, outputting a new `requirements_updated.txt`. Pay special attention to Django, DRF, Celery, and database connectors.
2. Scan the entire codebase for deprecated Django API usage (e.g., `url()` vs `path()`, `ugettext` vs `gettext`, changes in `HttpRequest`, `HttpResponse`, ORM, and middleware). Refactor the code to use the modern APIs.
3. Identify and update any Python 3.7 specific idioms or deprecated modules to their Python 3.11 equivalents.
4. Provide a detailed summary report of all major changes made, potential breaking changes that require manual review, and a list of files modified.
Do not execute tests, but flag areas that will likely need test updates.

Scenario Deep Dive:

A company needs to modernize a critical legacy web application to benefit from new features, security updates, and improved performance offered by newer versions of Django and Python. This is a daunting task involving deep analysis of dependency compatibility, widespread code changes to adapt to API deprecations, and careful testing. Manually undertaking such a migration is highly resource-intensive and carries a high risk of errors.

Codex in Action: Typical Outcome & Interaction

This is a complex task where the June 2025 Codex would shine by demonstrating its "AI Engineering Partner" capabilities.
Phase 1 (Analysis & Planning): Codex would first parse `requirements.txt`. It would cross-reference each package with compatibility information for Django 4.2 and Python 3.11 (leveraging its vast training data which includes knowledge of package ecosystems and changelogs). It would then generate `requirements_updated.txt`. It would also scan the entire codebase, building a dependency graph and identifying usages of known deprecated Django and Python patterns based on its knowledge of version changes.

Phase 2 (Code Refactoring): Codex would systematically refactor the identified code sections. For example, it would replace `url()` imports and usage with `path()` or `re_path()`, update deprecated middleware class structures, adjust ORM query patterns if needed, and handle changes in request/response object attributes.

Phase 3 (Reporting): Finally, Codex would generate a comprehensive Markdown report detailing:
  • A summary of the version changes for key dependencies.
  • A categorized list of API changes addressed (e.g., URL patterns, internationalization, ORM).
  • Specific examples of significant refactorings.
  • A list of all modified files.
  • A section on "Potential Manual Review Items," highlighting areas where the automated refactoring might be ambiguous or where related business logic might need re-validation (e.g., complex custom template tags, highly intricate database queries, or areas it flagged for needing test updates).
Codex would likely present the changes as a series of proposed commits or a large diff for the developer to review and then apply incrementally or all at once. It might ask clarifying questions during the process if it encounters highly ambiguous or project-specific patterns it cannot confidently refactor.
Benefits: Dramatically accelerates a complex and risky migration process, reduces manual error, provides a clear audit trail of changes, and helps identify areas requiring focused human attention.

4. Quality Assurance: Automated Code Review & Security Audit

The Prompt:

Review the changes in pull request #248 (feature-branch: 'new-user-feedback-module').
Focus on:
1. Potential security vulnerabilities: Specifically check for XSS in template rendering related to user feedback display, SQL injection possibilities in any new database interactions, and any obvious insecure direct object reference (IDOR) patterns.
2. Logic errors or significant deviations from best practices in the new Python and JavaScript code.
3. Adherence to our project's coding standards (documented in `CONTRIBUTING.md` - section "Code Style").
4. Lack of appropriate error handling or missing unit tests for new functionality.
Provide a structured report with file paths, line numbers, issue descriptions, and actionable suggestions for improvement. Assign a severity (Critical, High, Medium, Low) to each identified issue.

Scenario Deep Dive:

A development team uses pull requests (PRs) for code review. Ensuring thorough reviews that cover functionality, style, security, and test coverage can be a bottleneck, especially for large PRs. The goal is to leverage Codex to perform an initial, comprehensive review pass to catch common issues and allow human reviewers to focus on more nuanced architectural and business logic aspects.

Codex in Action: Typical Outcome & Interaction

Assuming Codex has access to the PR data (e.g., via GitHub integration or by being provided the diff and relevant project files, including `CONTRIBUTING.md`), it would perform a multi-faceted analysis:

  • Security Analysis: It would scan for common XSS patterns where user-supplied feedback is rendered, check database query construction for SQLi risks (looking for proper parameterization or ORM usage), and analyze how object IDs are used in new API endpoints or views for IDOR.
  • Logic & Best Practices: It would analyze the control flow, look for off-by-one errors, inefficient loops, unhandled exceptions, or use of deprecated/suboptimal library functions.
  • Style Adherence: It would parse `CONTRIBUTING.md` to understand the project's specific style rules (e.g., variable naming, import order, line length) and flag deviations in the new code.
  • Test & Error Handling Coverage: It would identify new functions or significant code paths and check if corresponding unit tests appear to be added or if error conditions seem unhandled.
The output would be a structured report, likely in Markdown, formatted for readability within a PR comment or a separate document:
## Codex PR Review: #248

### Critical Issues:
- **File:** `templates/feedback/view.html`, **Line:** 42
  - **Issue:** Potential XSS vulnerability. User-submitted `feedback_text` is rendered directly without sanitization.
  - **Suggestion:** Use Jinja2's `|e` filter or ensure proper sanitization library is applied.

### High Issues:
- **File:** `views/feedback_api.py`, **Line:** 78
  - **Issue:** SQL query constructed using string formatting with user input `category_id`. Potential SQLi.
  - **Suggestion:** Refactor to use parameterized queries or ORM filtering.

### Medium Issues:
- **File:** `static/js/feedback.js`, **Line:** 25
  - **Issue:** Missing error handling for AJAX request failure.
  - **Suggestion:** Add a `.catch()` block or equivalent to handle network errors or non-200 responses.
- **File:** `models/feedback.py`, **Line:** 15 (Class `FeedbackModel`)
  - **Issue:** Class name does not follow PascalCase as per `CONTRIBUTING.md`.
  - **Suggestion:** Rename to `FeedbackModel`.

### Low Issues:
- **File:** `views/feedback_views.py`, **Function:** `submit_feedback`
  - **Issue:** No unit test found for the new `submit_feedback` function.
  - **Suggestion:** Add unit tests covering successful submission and error cases.
Benefits: Catches a wide range of issues early, improves overall code quality and security, reduces the burden on human reviewers, and helps enforce consistency.

5. Code Comprehension: Explaining Complex Systems & Generating Diagrams

The Prompt:

I'm new to the 'notification-service' module in our microservices architecture. It's written in Go. Please provide:
1. A high-level explanation of its primary responsibilities and how it interacts with other services (like 'user-service' and 'order-service').
2. A breakdown of the main components/packages within 'notification-service' and their roles.
3. An explanation of the error handling strategy and logging mechanisms used.
4. Generate a Mermaid sequence diagram illustrating the typical flow when a new order is placed and a notification needs to be sent to the user.
Assume you have access to the 'notification-service', 'user-service', and 'order-service' repositories.

Scenario Deep Dive:

A developer is onboarding to a new team or needs to understand a complex, unfamiliar part of a large system. Reading through extensive codebases without guidance can be incredibly time-consuming and inefficient. They need a structured explanation and visual aids to quickly grasp the system's architecture and behavior.

Codex in Action: Typical Outcome & Interaction

Codex would leverage its multi-repository understanding to analyze the specified services.

Outcome Document (likely Markdown):
**1. High-Level Responsibilities & Interactions:** Codex would describe that the `notification-service` is responsible for dispatching various types of notifications (email, SMS, push) to users based on events from other services. It would identify API calls or message queue topics it subscribes to from `order-service` (e.g., "order_created") and how it might query `user-service` for contact details.

**2. Main Components Breakdown:** It might list packages like `internal/broker` (for Kafka/RabbitMQ connections), `internal/transports` (for email/SMS providers), `internal/templates` (for notification messages), and `internal/core` (for business logic), explaining each one's role.

**3. Error Handling & Logging:** Codex would identify common error handling patterns (e.g., custom error types, retry mechanisms for sending notifications) and how logging is implemented (e.g., structured logging with specific fields like `trace_id`, `user_id`).

**4. Mermaid Sequence Diagram:** It would generate a text-based diagram like this: ```mermaid sequenceDiagram participant Client participant OrderService as OS participant NotificationService as NS participant UserService as US Client->>+OS: Place Order OS->>OS: Process Order OS-->>-Client: Order Confirmation (ID) OS->>NS: Event: new_order (orderID, userID) NS->>+US: GetUserDetails(userID) US-->>-NS: UserDetails (email, phone) NS->>NS: Prepare Notification (template, userDetails) NS->>ExternalProvider: Send Email/SMS ExternalProvider-->>NS: Delivery Status NS->>NS: Log Notification Status ``` Benefits: Drastically reduces onboarding time, provides a clear and structured understanding of complex modules, helps in identifying points of failure or areas for improvement, and generates useful documentation artifacts.

Maximizing Success: Reviewing Codex's Output

While the June 2025 Codex is remarkably capable, it is crucial to cultivate a habit of meticulous review. Never assume AI-generated code or analysis is infallible. Always:

  • Verify Correctness: Does the code do what you intended? Does it handle edge cases? Test it thoroughly.
  • Assess Security: Scrutinize for potential vulnerabilities, especially if the code handles sensitive data or user inputs. Do not rely solely on Codex for security.
  • Evaluate Performance: Is the generated code efficient? Could it lead to bottlenecks, especially in loops or data-intensive operations?
  • Check for Style & Maintainability: Does the code adhere to your project's coding standards, architectural patterns, and general best practices for readability and long-term maintenance?