# Git History Investigation

> Reconstruct change history using log/show/diff/blame evidence to explain when and why behavior changed. Use when teams need evidence-based history analysis for regressions or ownership questions; do not use for CI workflow design or application behavior implementation. Use when this capability is needed.

- Skill: `tomevault-io/git-history-investigation` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tomevault-io/git-history-investigation`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/git-history-investigation/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: tomevault-io (https://skillmd.com/u/tomevault-io)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tomevault-io/git-history-investigation

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# Git History Investigation

## Overview
Use this skill to produce an auditable evidence chain from symptom to likely root-cause commits.

## Scope Boundaries
- Use this skill when the task matches the trigger condition described in `description`.
- Do not use this skill when the primary task falls outside this skill's domain.

## Shared References
- Evidence quality rules:
  - `references/history-evidence-quality-rules.md`

## Templates And Assets
- Investigation log:
  - `assets/history-investigation-log-template.md`
- Root-cause hypothesis template:
  - `assets/root-cause-hypothesis-template.md`

## Inputs To Gather
- Reproducible symptom or unexpected behavior.
- Candidate paths/modules and relevant time window.
- Issue/PR/review metadata for context.
- Required confidence threshold for decision-making.

## Deliverables
- Chronological evidence trail.
- Root-cause hypothesis with alternative hypotheses.
- Confidence-rated conclusion and next action recommendation.

## Workflow
1. Define scope and symptom timeline in `assets/history-investigation-log-template.md`.
2. Gather direct evidence from log/show/diff/blame.
3. Form and test hypotheses with `assets/root-cause-hypothesis-template.md`.
4. Apply `references/history-evidence-quality-rules.md` to validate claim strength.
5. Publish findings and root-cause-oriented follow-up actions.

## Quality Standard
- Evidence chain links symptom timeline to concrete commit behavior.
- Root-cause claim includes supporting and disconfirming evidence.
- Alternatives are explicitly considered and resolved.
- Follow-up actions address cause, not just surface symptoms.

## Failure Conditions
- Stop when symptom cannot be scoped to a meaningful history window.
- Stop when evidence is mostly inferential without diff-level support.
- Escalate when confidence is too low for production-impacting decisions.

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<!-- tomevault:4.0:skill_md:2026-04-14 -->