Autonomous growth experimentation framework. Creates A/B/multivariate experiments with hypotheses, logs data points, runs statistical analysis (bootstrap CI + Mann-Whitney U), auto-promotes winners to a living playbook, and suggests next experiments.
SkillScore83Maintained
Automatic
◆Marketing & Content pack
Last verified 8/19/2026
What it changes
Passed 17 of 20 test cases with the skill, and 3 of 20 without it.
Without skill13%
With skill83%
Checks it passed that the model alone missed
10
15%
400
and 26 more in the full report
18 fixed1 passed either way2 still failing2 broke
Pass-rate lift
+70 pp
Tokens
-1%
Agent turns
0%
Response time
-68%
Model gemini-3.6-flashMeasured 8/19/2026v119 of 23 cases passed with skill · 20 comparable
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 16 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 16
Prompt
We just published variant 'headline_b' for our blog article experiment EXP-202 on the blog channel. The preliminary metrics show 150 clicks and 12 conversions. Please record this data point into the growth engine.
What was checked, without and with the skill
Checked
Without skill
With skill
python3 experiment-engine.py log
Missed
Passed
--agent blog
Missed
Passed
--experiment-id EXP-202
Missed
Passed
case-07 · gemini-3.6-flash · 8/19/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md130 linessingle file
Growth Engine
Autonomous growth experimentation framework based on Karpathy's autoresearch pattern applied to marketing. Creates experiments with hypotheses, logs data points, runs statistical analysis (bootstrap CI + Mann-Whitney U), auto-promotes winners to a living playbook, and suggests next experiments. Supports batch mode (up to 10 variants simultaneously).
Usage
Use this skill when:
Creating or managing A/B or multivariate experiments for any marketing channel
Logging experiment data points after content is published or campaigns run
Scoring experiments to determine statistical winners
Checking the playbook for proven best practices before creating new content
Generating weekly scorecards across all channels
Monitoring campaign pacing and health
Do NOT use for:
One-off content creation (use the playbook output as input, but don't run the engine)
Non-experiment analytics or reporting
Campaign setup in external platforms (this tracks experiments, not campaign config)
Run a comprehensive SEO audit — keyword research, on-page analysis, content gaps, technical checks, and competitor comparison. Use when assessing a site's SEO health, when finding keyword opportunities and content gaps competitors own, or when you need a prioritized action plan split into quick wins and strategic investments.