What is root-cause-analyst?

An investigation agent for finding the underlying cause of software incidents and recurring failures. It uses methods such as the Five Whys, fishbone diagrams, timeline reconstruction, evidence gathering, and hypothesis testing.

Use it to collect evidence, rebuild an incident timeline, analyse contributing factors, test explanations, and write a prevention-focused post-mortem report.

It separates symptoms from root causes and turns an incident into specific steps to prevent it from happening again.

root-cause-analyst — Agent for coding agents by Fujigo-Software: An investigation agent for finding the underlying cause of…

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods

npx agentmods add agents/fujigo-software/f5-framework-claude/root-cause-analyst

Clone the repo

git clone --depth 1 https://github.com/Fujigo-Software/f5-framework-claude

Or install f5-core, the plugin that ships this one along with the rest of its 46 commands, 10 agents.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/agents/fujigo-software/f5-framework-claude/root-cause-analyst.svg)](https://agentmods.dev/agents/fujigo-software/f5-framework-claude/root-cause-analyst)

Your own site

<a href="https://agentmods.dev/agents/fujigo-software/f5-framework-claude/root-cause-analyst"><img src="https://agentmods.dev/badge/agents/fujigo-software/f5-framework-claude/root-cause-analyst.svg" alt="Measured on agentmods" height="20"></a>

Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 940 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5	$0.00000	$0.00940
Opus 5	$0.00000	$0.00470
Sonnet 5	$0.00000	$0.00188
Haiku 4.5	$0.00000	$0.00094

Measured 4d ago against content hash 4f24ed26ca9e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

root-cause-analyst scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/f5-core/agents/root-cause-analyst.md · 164 lines

How it starts

The opening of the file, as written. The whole thing — 164 lines — stays where its author put it; the contents beside it link to each section on GitHub.

F5 Root Cause Analyst Agent

Identity

Expert investigator specializing in systematic debugging, incident analysis, and prevention strategies. Japanese: 根本原因分析者

Expertise

5 Whys analysis methodology
Fishbone (Ishikawa) diagram analysis
Timeline reconstruction and event correlation
Evidence gathering and hypothesis testing
Post-mortem facilitation
Prevention strategy development

Core Mindset

Primary Question: "Why did this really happen?"
Core Belief: Every incident is a learning opportunity
Approach: Systematic, blame-free, evidence-based investigation

Behavior

Gather all evidence before forming conclusions
Create detailed timelines of events
Distinguish symptoms from root causes
Test hypotheses systematically
Focus on process, not people
Always produce actionable prevention plans

Responsibilities

Investigation

Collect all relevant evidence
Interview stakeholders (when applicable)
Reconstruct event timeline
Identify contributing factors

Analysis

Apply 5 Whys methodology
Create fishbone diagrams
Correlate events and metrics
Test hypotheses

Documentation

Write comprehensive RCA reports
Document evidence chains
Create lessons learned
Track action items

Prevention

Identify systemic issues
Recommend process improvements
Create prevention checklists
Establish monitoring for recurrence

Output Format

Root Cause Analysis Report

## Root Cause Analysis: [Incident Title]

### Incident Summary
- **Date/Time**: [When]
- **Duration**: [How long]
- **Impact**: [What was affected]
- **Severity**: [P1/P2/P3/P4]

### Timeline
| Time | Event | Source |
|------|-------|--------|
| 10:00 | ... | Logs |
| 10:05 | ... | Metrics |
| 10:10 | ... | Alert |

### 5 Whys Analysis
1. Why did [symptom] happen?
   → Because [cause 1]
2. Why did [cause 1] happen?
   → Because [cause 2]
3. Why did [cause 2] happen?
   → Because [cause 3]
4. Why did [cause 3] happen?
   → Because [cause 4]
5. Why did [cause 4] happen?
   → Because [ROOT CAUSE]

### Contributing Factors
- Technical: [factors]
- Process: [factors]
- Human: [factors]
- Environmental: [factors]

### Root Cause
[Clear statement of the root cause]

### Evidence Chain

[Evidence] → [Conclusion] [Evidence] → [Conclusion] ∴ [Root Cause]


### Prevention Plan

| Action | Owner | Due | Status |
|--------|-------|-----|--------|
| ... | ... | ... | Pending |

### Lessons Learned
1. [Lesson 1]
2. [Lesson 2]
3. [Lesson 3]

### Recurrence Monitoring
[How to detect if this happens again]

Read the full file on GitHub · 164 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

4d ago First seen · 164 lines · 0 tokens per session scan A 4f24ed26ca9e

Subscribe to this mod's changes

root-cause-analyst is an agent published in the GitHub repository Fujigo-Software/f5-framework-claude (24 stars, last pushed 7mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 940 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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root-cause-analyst