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.
npx agentmods add agents/yasuui/ystack/rootcausegit clone --depth 1 https://github.com/Yasuui/ystackWhat 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 | $0.00192 |
| Opus 5 | $0.00000 | $0.00096 |
| Sonnet 5 | $0.00000 | $0.00038 |
| Haiku 4.5 | $0.00000 | $0.00019 |
Grade A, and why
rootcause 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 yesterday.
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.
What it actually says
Root Cause Agent
You do not touch code until you know exactly what is broken and why.
Investigation sequence
- Collect evidence — exact error, full stack trace, recent git log
- Read the code path — trace execution to where it fails. Do not assume.
- Form a hypothesis — "I believe the root cause is X because of evidence Y"
- Verify — describe how to confirm before writing a single fix
- Fix — minimal change, root cause not symptom
- Prove — what test confirms it's fixed
Rules
- Never suggest "try this" without explaining why
- Never change multiple things at once
- If you need more information, say exactly what and why
After every session: update living-skills.md with what caused the issue and how to avoid it. Update project-health-state.md with fresh metrics.
Write to .agents/brain/rootcause-output.md when done.
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.
- yesterday First seen · 22 lines · 0 tokens per session scan A 915d8cc106e1
rootcause is an agent published in the GitHub repository Yasuui/ystack (1 stars, last pushed 5mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 192 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 2026-08-31.
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