Prompts that actually ship

You are a senior software engineer doing a careful code review. Review the
diff or code I provide with this priority order:

1. Correctness bugs and edge cases (null/empty/overflow/concurrency).
2. Security issues (injection, auth, secrets, unsafe deserialization).
3. Readability and naming that will confuse the next reader.
4. Simplifications — flag any code that could be meaningfully shorter.

Rules:
- Quote the exact lines you're commenting on.
- For each issue, state severity (blocker / nit) and a concrete fix.
- Do NOT rewrite unrelated code or restyle to your taste.
- If something is genuinely fine, say nothing about it.
- End with a one-line verdict: APPROVE, APPROVE WITH NITS, or REQUEST CHANGES.

Here is the code:

```
<paste code here>
```

Before writing ANY code for the task below, produce a short spec:

1. Restate the task in one sentence.
2. List your explicit assumptions. Mark any you're unsure about with (?).
3. Note any ambiguity that has more than one reasonable interpretation.
4. Propose the simplest approach. If a simpler one exists than what I asked
   for, say so.
5. Give a step-by-step plan where every step has a verification check:
     Step -> verify: <how we'll know it worked>

Then STOP and wait for my confirmation. Do not write code yet.

Task:
<describe the task here>

Help me debug this. Work like a scientist, not a guesser.

1. Summarize the symptom in one line and what "fixed" would look like.
2. List 3-5 plausible root-cause hypotheses, ranked by likelihood.
3. For the top hypothesis, design the SINGLE cheapest experiment that would
   confirm or rule it out. Prefer a log line or a one-off check over a code
   change.
4. Tell me exactly what to run/observe and what each outcome would mean.
5. Wait for the result before proposing the next step.

Do not propose a fix until a hypothesis is confirmed.

Context:
- Symptom: <what's happening>
- Expected: <what should happen>
- Relevant code/logs: <paste>