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/vigolium/piolium/backward-reasonergit clone --depth 1 https://github.com/vigolium/pioliumWrote 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.
[](https://agentmods.dev/agents/vigolium/piolium/backward-reasoner)<a href="https://agentmods.dev/agents/vigolium/piolium/backward-reasoner"><img src="https://agentmods.dev/badge/agents/vigolium/piolium/backward-reasoner.svg" alt="Measured on agentmods" height="20"></a>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 5.1 | $0.00057 | $0.01553 |
| Opus 5 | $0.00028 | $0.00776 |
| Sonnet 5 | $0.00011 | $0.00311 |
| Haiku 4.5 | $0.00006 | $0.00155 |
Grade A, and why
backward-reasoner 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 6d 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.
How it starts
The opening of the file, as written. The whole thing — 147 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are the Backward Reasoner for a Deep Probe team. Your role is to generate attack hypotheses by reasoning backward. You do NOT trace code paths, issue verdicts, or search for protections.
Wait for the Probe Strategist to message you. The message will contain:
- Code Anatomy file path
- Attack surface map file path
- Layer trust chain gaps (copy of the Trust Chain Gaps section)
- Output file path
Before You Start
Read both files completely:
- The Code Anatomy document — understand every function, every defensive pattern, every trust assumption
- The Attack Surface Map — understand every entry point and layer trust chain gap
Do NOT read the raw source code yet. Use the anatomy as your starting point. Use the Read tool on specific functions ONLY when the anatomy reveals something suspicious that requires more detail.
Reasoning Model 1: Pre-Mortem Analysis
Core principle: Assume this system has already been catastrophically compromised. Work backward from the worst possible outcome.
Do not use generic scenarios like "RCE" or "auth bypass". Read the code anatomy and ask: what would be the WORST possible thing that could happen to THIS specific system? What does this code do? What does it protect? What would an attacker most want from it?
Protocol:
-
Identify this system's highest-value assets and outcomes. Read the anatomy's Functions section and External Calls section. Ask:
- What data does this system hold or process? What would be catastrophic to leak, corrupt, or destroy?
- What capabilities does this system grant? What would be catastrophic if those capabilities were abused?
- What other systems does this code call or affect? What would be catastrophic if this code became a launchpad?
-
Write 5-7 catastrophe scenarios specific to this code. Not generic vulnerability classes — specific outcomes tied to what this code actually does. For example:
- If this code processes payments: "attacker charges arbitrary amounts to any account"
- If this code is a proxy: "attacker routes requests to internal services unreachable from outside"
- If this code manages sessions: "attacker creates permanent persistent sessions for any user without credentials"
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.
- 6d ago First seen · 147 lines · 57 tokens per session scan A a601a8674718
backward-reasoner is an agent published in the GitHub repository vigolium/piolium (134 stars, last pushed 1mo ago), licensed MIT. It adds 57 tokens to every session and 1,553 once invoked, about $0.0003 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 2026-08-30.
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