hypothesis-falsifier

hypothesis-falsifier is an agent for Claude Code from galilei2050/belay. It costs 99 tokens per session (900 once invoked), scanned A, original, AGPL-3.0.

An investigation agent that challenges a single explanation which already has supporting evidence.

In plain words
What is it for?
Use it to test one proposed cause in an investigation by checking it from seven different angles and gathering additional evidence.
Why use it?
It helps reveal alternative causes, weak evidence, timing problems, selection bias, and other reasons an explanation might be wrong.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter.

Part of the deep-investigation plugin — 1 skill, 3 agents shipped together

Good fit Use it to test one proposed cause in an investigation by checking it from seven different angles and gathering additional evidence.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/galilei2050/belay/hypothesis-falsifier
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/galilei2050/belay

Made for: Claude Code.

Or install deep-investigation, the plugin that ships this one along with the rest of its 1 skill, 3 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.

agentmods badge for hypothesis-falsifier

README.md
[![agentmods](https://agentmods.dev/badge/agents/galilei2050/belay/hypothesis-falsifier/github.svg)](https://agentmods.dev/agents/galilei2050/belay/hypothesis-falsifier)
Your own site
<a href="https://agentmods.dev/agents/galilei2050/belay/hypothesis-falsifier"><img src="https://agentmods.dev/badge/agents/galilei2050/belay/hypothesis-falsifier/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 hypothesis-falsifier

Your own site · 80×15
<a href="https://agentmods.dev/agents/galilei2050/belay/hypothesis-falsifier"><img src="https://agentmods.dev/badge/agents/galilei2050/belay/hypothesis-falsifier.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 99 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 900 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 unknown 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 $0.00099 $0.00900
Opus 5 $0.00049 $0.00450
Sonnet 5 $0.00020 $0.00180
Haiku 4.5 $0.00010 $0.00090

Measured 9d ago against content hash da9ea29e4f7b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

hypothesis-falsifier 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 9d 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/deep-investigation/agents/hypothesis-falsifier.md · 83 lines

The source is not reproduced here

Licensed AGPL-3.0

The repository is licensed AGPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

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. 9d ago First seen · 83 lines · 99 tokens per session scan A da9ea29e4f7b

Subscribe to this mod's changes

hypothesis-falsifier is an agent published in the GitHub repository galilei2050/belay (2 stars, last pushed 8d ago), licensed AGPL-3.0. It adds 99 tokens to every session and 900 once invoked, about $0.0005 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.