# Investigate First (investigate-first)

> Diagnoses ambiguous failures by gathering evidence and ranking hypotheses before any product code is changed.

- Category: [Testing & Debugging](https://www.myskills.tools/en/categories/testing-debugging/)
- Source: Community · Julius Brussee
- Repository: https://github.com/JuliusBrussee/caveman/tree/main/skills/investigate-first (commit 82864c8)
- SKILL.md: https://github.com/JuliusBrussee/caveman/blob/main/skills/investigate-first/SKILL.md
- Install command: `npx skills add JuliusBrussee/caveman --skill investigate-first`
- License: Apache-2.0
- Compatible with: Claude Code, Codex, Gemini CLI
- Permissions: read-repo ✓, write-files ✗, shell ✗, network ✗
- Status: Scan passed
- A rule scan cannot catch every risk. Read this skill's SKILL.md and check its permissions before installing.

## Core rule

Do not edit until one credible mechanism explains the evidence.

## Execution Phases

1. **Separate symptom and cause** — Keep the observed symptom apart from the inferred cause.
2. **Trace** — Trace inputs, state transitions, ownership boundaries and failure output.
3. **Rank hypotheses** — Rank hypotheses by evidence and cheap falsification value, and stop once evidence is sufficient.
4. **Report cause and proof** — Report the cause and proof or the exact blocker; make no fix unless the task authorizes it.

## Permissions (summarised from SKILL.md)

| Capability | Needed | Details |
|---|---|---|
| File writes | Limited | Does not change product code during investigation; fixes only when the task authorizes implementation. |
| Command execution | Not required | The skill does not call for specific commands. |
| Network outbound | Not required | The skill does not call for network access. |

## SKILL.md frontmatter (YAML)

```yaml
---
name: investigate-first
description: Diagnose ambiguous failures before editing. Use for unknown causes, intermittent behavior, performance regressions, or investigations needing evidence-ranked hypotheses.
---
```

Home: https://www.myskills.tools/en/ · URL: https://www.myskills.tools/en/skills/investigate-first/