| name | reproduce-bug |
| description | Step-by-step procedure to reproduce a bug. Use this FIRST before trying to fix anything. Produces a minimal script that demonstrates the failure.
|
Reproduce Bug
You are reproducing a bug. Follow these steps exactly in order. Do not skip
steps or read additional files beyond what each step specifies.
Step 1: Identify the test framework
ls package.json 2>/dev/null && cat package.json | grep -E "vitest|jest|mocha|tap" | head -5
ls *.toml 2>/dev/null | head -3
Note which test runner is available (vitest, jest, etc.).
Step 2: Find existing related tests
find . -name "*.test.*" -o -name "*.spec.*" | grep -i "<keyword from bug description>" | head -10
If you find relevant test files, read them to understand how the codebase
tests similar functionality.
Step 3: Write a minimal reproduction script
Create a file called repro.ts (or repro.js / repro.py depending on
the project language) that:
- Imports the minimum necessary from the project
- Sets up the simplest possible environment (in-memory DB, mock server, etc.)
- Calls the function/endpoint described in the bug
- Prints ACTUAL output clearly
- Prints EXPECTED output clearly
- Prints PASS or FAIL
Keep it under 50 lines. Use the write tool to create the file.
Step 4: Run the reproduction
npx tsx repro.ts 2>&1
Or the appropriate runner for the language. Report:
- Exit code
- ACTUAL vs EXPECTED output
- Whether the bug is confirmed
Step 5: Report result
State clearly:
- "BUG CONFIRMED: [one-line description of what goes wrong]"
- OR "BUG NOT REPRODUCED: [what happened instead]"
If not reproduced, adjust the repro script (maybe the setup is wrong) and
try ONE more time. If still not reproduced after 2 attempts, report that.
Constraints
- Do NOT read source code in this skill. You are only writing and running
a reproduction script.
- Do NOT try to fix the bug. Only reproduce it.
- Maximum 8 tool calls for this entire skill.
