Investigate First

by JuliusBrussee

Investigate First is a Quality skill for Claude Code, published by JuliusBrussee in caveman.

97.8K stars5.6K forkson JuliusBrussee/cavemanAdded 2026/08/13Repository updated 2026/08/13

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Install in seconds

Install Investigate First

Copy Investigate First into your Claude Code skills folder. Run the command in your terminal, or review the source on GitHub before installing.

terminal

npx degit https://github.com/JuliusBrussee/caveman/tree/main/skills/investigate-first ~/.claude/skills/investigate-first

Requires Node.js. Downloads this skill only — not the rest of the repository — into your Claude Code skills folder.

Without Node.js

git clone https://github.com/JuliusBrussee/caveman.git

Clones the whole repository, then copy the skill’s own directory into your skills folder yourself.

In this catalog

Source file: skills/investigate-first/SKILL.md in JuliusBrussee/caveman
Installs to: ~/.claude/skills/investigate-first
Collection: One of 20 skills cataloged from this repository
Category: Quality — 1354 skills

What Investigate First does

Investigate First diagnoses ambiguous failures before editing code. Use it when the cause is unknown, behavior is intermittent, or you need evidence-ranked hypotheses before changing product code.

Investigate First is cataloged under Quality on DirSkills. Investigate First comes from a repository tagged ai, anthropic, caveman, claude and claude-code.

Documentation

README

From the original repository

Investigate first

Gather evidence before changing product code.

Separate observed symptom from inferred cause.
Trace inputs, state transitions, ownership boundaries, and failure output.
Rank hypotheses by evidence and cheap falsification value.
Do not edit until one credible mechanism explains evidence.
Stop exploration when evidence is sufficient to name cause or exact blocker.

Report cause and proof. Make no fix unless task authorizes implementation.

Frequently asked about Investigate First

What else does JuliusBrussee publish alongside Investigate First?
Investigate First is one of 20 skills that DirSkills catalogs from JuliusBrussee/caveman, the repository it ships in. Its siblings there include Cavecrew, Caveman and Caveman Commit. Each one is a separate skill with its own page in this directory, installs the same way Investigate First does, and is maintained by JuliusBrussee in that same repository. The rest of the collection is listed on the JuliusBrussee/caveman page.
How does Investigate First compare to other Quality skills?
Investigate First ranks #15 by stars among the 1354 Quality skills in this catalog. The most-starred ones next to it are Benchmark, Benchmark Optimization Loop and API Design Patterns. DirSkills ranks by the star count of the repository each skill ships in, so that order reflects how popular those repositories are rather than any review of Investigate First against them. Open each page to compare what they document and how they install.