| name | debug-seb |
| description | Diagnose and fix a bug using the SEB method (Screenshot, Error message, Before/After) plus the bisect trick for unknown regressions, gathering real evidence before guessing at a fix. This is the fuller version of /fix-bug — use directly for trickier bugs or when the quick pass doesn't find the cause. |
Debug (SEB method)
The founder can't read a stack trace, but can take a screenshot and copy
error text. The job here is to force evidence collection before guessing,
with a deterministic fallback for when there's no clear "before."
What to do
-
Collect S-E-B before touching code — don't skip to "just fix it."
Screenshot: use the playwright MCP server to capture one if the
founder can't easily grab it themselves — it's local browser automation
and explicitly "not a security boundary," so it's fine to use freely.
Error text: copied verbatim, not paraphrased — ask again if it was
paraphrased. Before/after: the last change before it broke, if
known.
-
If "last working state" is unknown, bisect the recent history. Don't
stop after an arbitrary number of commits — search backward, testing
after each step, until you isolate the actual first bad commit. A fixed
3-commit rollback can miss a regression introduced further back.
-
Diagnose in plain terms what went wrong before fixing — one or two
sentences, no code-level jargon the founder can't use.
-
Fix only the isolated cause, not surrounding code, to avoid
introducing a second regression while chasing this one.
-
Verify with /verify-path before declaring it fixed, confirming
the step-1 repro no longer reproduces.
Anti-patterns to avoid
- Starting to fix before there's at least error text or a screenshot in
hand.
- Bisecting "by feel" instead of one discrete committed change at a time,
with an actual test after each undo.
- Fixing more than the isolated cause "while in there" — that's a
refactor, not a bug fix; route it through
/refactor-safely instead.
