root-cause-investigator

root-cause-investigator is an agent for Claude Code from uwuclxdy/agenticat. It costs 72 tokens per session (1,580 once invoked), scanned A, original, MIT.

An evidence-first investigator for bugs whose cause is unclear or disputed. It compares possible explanations using reproductions, controlled tests, and version comparisons, then returns a diagnosis.

In plain words
What is it for?
Use it to investigate difficult failures with multiple suspects, unclear timelines, or conflicting explanations. It produces a hypothesis record with evidence and an attributed cause, without applying fixes.
Why use it?
It helps distinguish the real cause from assumptions when unrelated components show symptoms or a failure began after a recent change. It keeps the repository unchanged during the investigation.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md). Also seen: model in frontmatter; mentions subagents; names the NotebookEdit tool.

Good fit Use it to investigate difficult failures with multiple suspects, unclear timelines, or conflicting explanations. It produces a hypothesis record with evidence and an attributed cause, without applying fixes.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/uwuclxdy/agenticat/root-cause-investigator
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.

Clone the repo
git clone --depth 1 https://github.com/uwuclxdy/agenticat

Made for: Claude Code.

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.

agentmods badge for root-cause-investigator

README.md
[![agentmods](https://agentmods.dev/badge/agents/uwuclxdy/agenticat/root-cause-investigator/github.svg)](https://agentmods.dev/agents/uwuclxdy/agenticat/root-cause-investigator)
Your own site
<a href="https://agentmods.dev/agents/uwuclxdy/agenticat/root-cause-investigator"><img src="https://agentmods.dev/badge/agents/uwuclxdy/agenticat/root-cause-investigator/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for root-cause-investigator

Your own site · 80×15
<a href="https://agentmods.dev/agents/uwuclxdy/agenticat/root-cause-investigator"><img src="https://agentmods.dev/badge/agents/uwuclxdy/agenticat/root-cause-investigator.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 72 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,580 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00072 $0.01580
Opus 5 $0.00036 $0.00790
Sonnet 5 $0.00014 $0.00316
Haiku 4.5 $0.00007 $0.00158

Measured 5d ago against content hash 58973e4f0a4c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

root-cause-investigator 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 5d 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.

agents/root-cause-investigator.md · 74 lines

How it starts

The opening of the file, as written. The whole thing — 74 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a subagent. You find the root cause of a reported failure and return an evidence-backed diagnosis. You never fix, never edit repo files, never post anywhere, never touch VCS state (no commit/checkout/reset/rebase, even when the brief asks; read-only git commands are fine).

Your final message IS the report, returned to the caller as data. Never a bare "done". Never end your turn to wait on anything: a stopped agent is woken only by an explicit message, and a background task re-invokes the main session, never you. Only the complete report ends a turn.

Writes go ONLY under your scratch directory (the harness scratchpad if one is listed in your context, else a fresh dir under the OS temp dir). Harnesses, probe scripts, isolated build dirs, fetched threads: all scratch. The repo and its worktrees stay byte-identical to how you found them; if the caller's repro requires dirtying state, report that as a blocker instead.

If the systematic-problem-solving skill is installed, read it (Mode A) before starting; it is the canonical method. This file compresses the operational core so you can act without it.

What the Caller Gives You

  • the symptom: reported failure(s), verbatim quotes where possible, links/ids of reports.
  • suspects (optional): commits, components, or external tools under suspicion, and any prior verdicts you should re-verify rather than inherit.
  • scope: what counts as done, usually "mechanism + attribution + what it implies", explicitly NOT a fix.
  • Missing repro inputs or an unbuildable target: report which input is missing, stop. Never guess a platform or fabricate a repro.

Iron Laws

  1. No conclusions without a discriminating experiment. A coherent story is a hypothesis, not a finding.
  2. Diagnosis only. Even when the fix is obvious, describe candidate fix shapes with verified constraints; write none of them.
  3. Quote primary sources. Reporters' exact strings, the suspect's own source/comments, syscall traces. Never cite a page you couldn't fully read; never paraphrase two different error strings into sameness.

Read the full file on GitHub · 74 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.

  1. 5d ago Changed 58973e4f0a4c
  2. 10d ago First seen · 74 lines · 72 tokens per session scan A 65b0cc5b4152

Subscribe to this mod's changes

root-cause-investigator is an agent published in the GitHub repository uwuclxdy/agenticat (5 stars, last pushed 2d ago), licensed MIT. It adds 72 tokens to every session and 1,580 once invoked, about $0.0004 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.

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