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.