Passed 3 of 8 test cases with the skill, and 5 of 8 without it.
Without skill67%
With skill33%
Checks it passed that the model alone missed
Includes a nearby regression check in verification.
Provides direct runtime evidence from HTTP header checks.
2 fixed2 passed either way14 still failing5 broke
Pass-rate lift
-33 pp
Tokens
-31%
Agent turns
0%
Response time
-27%
Model gemini-3.6-flashMeasured 8/14/2026v14 of 23 cases passed with skill · 8 comparable
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 2 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 2
Prompt
The payments microservice in Node.js shows monotonically increasing RSS memory usage under steady synthetic load in staging. We need to debug this bug. Provide a diagnostic analysis and fix report.
What was checked, without and with the skill
Checked
Without skill
With skill
States expected baseline memory behavior alongside the symptom.
Passed
Passed
Evaluates evidence for at least three potential memory leak sources.
Passed
Passed
Includes a nearby regression check in verification.
Missed
Passed
case-07 · gemini-3.6-flash · 8/14/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md31 linessingle file
gstack-investigate
Use this skill to diagnose before fixing.
Workflow
State the observed symptom and the expected behavior.
Reproduce the issue with the smallest command, UI flow, fixture, or log slice available.
Trace the relevant path through the code before proposing a fix.
Form at least three plausible causes.
Test the causes with targeted checks, logs, assertions, or isolated commands.
Pick the cause with the strongest evidence.
Apply the smallest fix that addresses that cause.
Re-run the original reproduction and one nearby regression check.
Rules
Do not fix before reproduction or strong evidence.
If one attempted fix fails, record why and try a different strategy.
Prefer direct runtime evidence: command output, logs, API responses, persisted state, or failing tests.