skeptic

skeptic is an agent for Claude Code from Miguok/fable-harness. It costs 66 tokens per session (327 once invoked), scanned A, original, MIT.

A skeptical reviewer that assumes a conclusion may be wrong and searches for unsupported assumptions, logical gaps, and counterexamples.

In plain words
What is it for?
Use it to check conclusions, designs, or suspected bug causes by inspecting files and identifying untested assumptions or reproducible failure cases.
Why use it?
It makes claims face evidence and realistic cases that could disprove them before they are accepted.

Agent for Claude Code

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 agents/miguok/fable-harness/skeptic
Clone the repo
git clone --depth 1 https://github.com/Miguok/fable-harness

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 skeptic

README.md
[![agentmods](https://agentmods.dev/badge/agents/miguok/fable-harness/skeptic.svg)](https://agentmods.dev/agents/miguok/fable-harness/skeptic)
Your own site
<a href="https://agentmods.dev/agents/miguok/fable-harness/skeptic"><img src="https://agentmods.dev/badge/agents/miguok/fable-harness/skeptic.svg" alt="Measured on agentmods" height="20"></a>
Per session 66 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 327 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 $0.00066 $0.00327
Opus 5 $0.00033 $0.00163
Sonnet 5 $0.00013 $0.00065
Haiku 4.5 $0.00007 $0.00033

Measured 4d ago against content hash 42d5da5ba782, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

skeptic 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 4d 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.

.claude/agents/skeptic.md · 24 lines

What it actually says

你是抗辯流程中的「懷疑者」,預設立場:這個結論是錯的,證明它

收到待審結論後:

  1. 列出該結論依賴的所有假設(明示的與隱含的)。
  2. 逐一檢驗:哪些假設沒有證據?哪些可以用 Read/Grep/Bash 實際查證?去查。
  3. 主動構造反例:什麼輸入、什麼時序、什麼環境會讓這個結論不成立?
  4. 不確定時偏向否決(refuted),理由必須具體到檔案:行號或可重現步驟。

回傳格式(純資料,不加寒暄):

verdict: REFUTED | SURVIVED
confidence: high | medium | low
reasons:
- <具體理由,附 file:line 或反例>
untested_assumptions:
- <該結論仍依賴但你無法驗證的假設>
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. 4d ago First seen · 24 lines · 66 tokens per session scan A 42d5da5ba782

Subscribe to this mod's changes

skeptic is an agent published in the GitHub repository Miguok/fable-harness (201 stars, last pushed 8d ago), licensed MIT. It adds 66 tokens to every session and 327 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.