Use this skill when navigating unfamiliar codebases, understanding legacy code, onboarding to a new project, or reverse-engineering how something works. Trigger on keywords: unfamiliar code, legacy code, understand this codebase, how does this work, new project, onboarding, read code, trace through, what does this do.
SkillScore82Maintained
Automatic
◆Coding pack
Last verified 8/3/2026
What it changes
Passed 18 of 22 test cases with the skill, and 17 of 22 without it.
Without skill77%
With skill82%
Checks it passed that the model alone missed
Position test suites after key user flows in the onboarding sequence.
Position configuration and environment files after test suites as the seventh step.
1 fixed17 passed either way4 still failing0 broke
Pass-rate lift
+5 pp
Tokens
+1%
Agent turns
0%
Response time
-32%
Model gemini-3.6-flashMeasured 8/3/2026v118 of 22 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
See it in action
A test case the skill fixed. Same model, same prompt, with and without the skill.
Prompt
I'm setting up an onboarding guide for junior devs. A colleague suggested looking at config/.env files right after the README so devs know how to set up local environment variables. Where do config/env files and test suites actually belong in the systematic code reading onboarding order?
What was checked, without and with the skill
Checked
Without skill
With skill
Position test suites after key user flows in the onboarding sequence.
Missed
Passed
Position configuration and environment files after test suites as the seventh step.
Missed
Passed
case-03 · gemini-3.6-flash · 8/3/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md78 linessingle file
Code Reading
Core Principle
Code is read 10x more than it's written. Reading code is a skill you actively develop — not a passive activity.
Codebase Onboarding Order
Always explore a new codebase in this order:
README — What does it do? How do I run it?
Package/dependency files — What tools and frameworks are used?
Entry point — Where does execution start? (main.ts, index.js, app.py)
Core domain models — What are the main data structures?
Key user flows — Trace one important feature end-to-end
Tests — Tests reveal intended behavior and edge cases
Config/env files — What is configurable? What are the environments?
Code Tracing Method
For understanding a specific flow:
1. Start from the trigger (user action, API call, scheduled job)
2. Follow the execution path step by step
3. Note: what data flows in? what comes out?
4. Identify where external systems are called
5. Mark where business logic lives vs. infrastructure
Questions to Ask While Reading
What is this component responsible for? (single responsibility check)
What does it need to run? (dependencies)
What does it produce/return?
What could make it fail?
Why was it written this way? (check git blame/history for context)