tommymorgan:root-cause

A command that investigates a reported software problem using the five whys method, repeatedly asking why based on evidence until it finds an actionable root cause.

In plain words
What is it for?
Use it to analyze errors, bugs, or unexpected behavior, inspect code and logs, report each investigation level, and then implement the recommended fix.
Why use it?
It helps avoid guessing at fixes before understanding what actually caused the failure.

Command

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 commands/tommymorgan/claude-plugins/root-cause
Clone the repo
git clone --depth 1 https://github.com/tommymorgan/claude-plugins
Per session 19 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 271 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.

ModelPer sessionOnce invoked
Fable 5 $0.00019 $0.00271
Opus 5 $0.00010 $0.00135
Sonnet 5 $0.00004 $0.00054
Haiku 4.5 $0.00002 $0.00027

Measured 2d ago against content hash 715797432be7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

tommymorgan:root-cause 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 2d 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.

tommymorgan/debugging/commands/root-cause.md · 34 lines

What it actually says

Perform systematic root cause analysis on the reported problem using the root-cause-analyzer agent.

Problem Context: $ARGUMENTS

Instructions:

  1. Launch the root-cause-analyzer agent to investigate this problem
  2. The agent will autonomously perform five whys analysis without user prompts
  3. Each investigation level will be shown progressively as the agent works
  4. The agent will continue until identifying an actionable root cause
  5. After root cause is identified, proceed to implementing the fix

Agent Behavior:

  • Gathers evidence from code, logs, and outputs
  • Asks "why?" iteratively based on concrete findings
  • Shows structured output for each investigation level
  • Determines when root cause criteria are met (actionable, explanatory, terminal)
  • Completes automatically when root cause is found

Your Role:

  • Use the Task tool to launch the root-cause-analyzer agent
  • Provide the problem context to the agent
  • Wait for agent to complete root cause analysis
  • Once agent identifies root cause, proceed with the recommended fix approach

Do not attempt speculative fixes before root cause is identified.

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.

  1. 2d ago First seen · 34 lines · 19 tokens per session scan A 715797432be7

Subscribe to this mod's changes

tommymorgan:root-cause is a command published in the GitHub repository tommymorgan/claude-plugins (4 stars, last pushed 1mo ago), licensed MIT. It adds 19 tokens to every session and 271 once invoked, about $0.0001 per session on Opus 5. 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 2026-08-31.