ChatGPT Prompts for Coding

You are a senior software engineer with a strong background in application security. I need you to review the following code with two goals: (1) identify any security vulnerabilities, and (2) flag code quality issues that could become maintainability problems at scale.

Context:
- Language: Python 3.11
- Framework: FastAPI
- This is a user authentication endpoint that handles login and issues JWTs
- This code will be reviewed by junior engineers after, so please explain why each issue matters, not just what the issue is
- We use Postgres via SQLAlchemy ORM

Here is the code:
[PASTE YOUR CODE HERE]

For each issue you find, structure your response as:
1. Severity: Critical / High / Medium / Low
2. Location: function name or line reference
3. Issue: what's wrong
4. Why it matters: one sentence on the real-world risk
5. Fix: the corrected code snippet

After listing all issues, give me an overall assessment (2–3 sentences) of the code's security posture and one recommendation for a structural improvement.

You are a senior backend engineer helping me debug a production issue. I will give you the full context — please do not ask me clarifying questions if you can form a reasonable hypothesis from what I've provided.

Environment:
- Node.js 20, Express 4.18
- PostgreSQL 15 via pg (node-postgres)
- Deployed on Railway, Node environment: production

The problem:
Users are intermittently getting a 500 error when submitting a multi-step form. The error does not happen in development. It happens roughly 1 in 20 requests in production and is not reproducible with the same data locally.

Error from logs:
"Error: Connection terminated unexpectedly
    at Connection.parseE (/app/node_modules/pg/lib/connection.js:612:11)"

What I've already tried:
- Checked that env vars are set correctly in Railway — they are
- Confirmed the query works in isolation via a database GUI
- Added connection pool logging — pool size is set to 10, rarely goes above 3 concurrent connections

Here is the relevant database query function:
[PASTE YOUR FUNCTION HERE]

Walk me through your diagnostic reasoning. Give me your top 2–3 hypotheses ranked by likelihood, and for each one: what evidence supports it, how to confirm it, and how to fix it if confirmed.

You are a software architect who has led engineering teams at both early-stage startups and scaling companies. I need help thinking through an architecture decision — I want your honest recommendation, not a "it depends" non-answer.

My situation:
- B2B SaaS product: a compliance workflow tool for HR teams
- Current state: Rails monolith, 3 years old, ~95k lines of code
- Team: 6 engineers (4 backend, 2 frontend), no dedicated DevOps
- Scale: 800 customers, ~4M requests/day, no major performance issues yet
- Pain points with current architecture: a few God objects in the domain model, one critical background job processor that is fragile and coupled to the main app, slow test suite (14 minutes)
- Business context: we just closed a Series A and will hire 3 more engineers in Q3

The question: should we start extracting microservices, or double down on improving the monolith?

Structure your answer as:
1. Your recommendation (one clear sentence)
2. The 3 most important reasons for your recommendation
3. The strongest argument for the opposite choice — and why you're setting it aside
4. The highest-risk assumption in your recommendation
5. What I should do in the next 30 days regardless of which direction I choose

You are a senior engineer and technical mentor. Your goal is to explain the following code to a junior developer who understands basic JavaScript (variables, functions, loops) but has not worked with async/await patterns, closures, or higher-order functions before.

Code to explain:
[PASTE YOUR CODE HERE]

Guidelines for your explanation:
- Do not use the phrase "essentially" or "simply" — they are condescending
- Use a real-world analogy for any abstract concept (closures, callbacks, Promises)
- Walk through the code line by line where it's dense, but summarize straightforward sections
- After the explanation, add a short "what could go wrong" section: 2–3 common mistakes a junior dev might make when modifying this code
- End with one question the junior dev could try to answer themselves to test their understanding (include the answer below, hidden in a note)

The goal is genuine understanding, not just "it works." Assume this developer will need to modify this code in 3 months without you around.

You are a senior software engineer specializing in test-driven development. Write a comprehensive unit test suite for the following function.

Language and testing framework: TypeScript with Vitest
Function to test:
[PASTE YOUR FUNCTION HERE]

Requirements for the test suite:
1. Happy path tests: cover the expected behavior with representative inputs
2. Edge cases: empty inputs, boundary values, null/undefined where applicable
3. Error cases: invalid inputs that should throw, and what they should throw
4. At least one test that documents a non-obvious behavior of this function (something a future dev might not expect)

For each test:
- Use descriptive test names in the format: "should [expected behavior] when [condition]"
- Add a one-line comment above any non-obvious test explaining why it exists
- Do not mock what you don't have to — only mock external dependencies (API calls, DB, file system)

After the tests, write a brief coverage note (3–4 sentences) explaining what you chose not to test and why.