skeptic

A read-only agent that checks one claimed code-review problem against the actual code and tries to disprove it. It can also cross-check one research claim against its cited web sources and related claims.

In plain words
What is it for?
Use it before reporting a review finding, or to verify a single research claim and its supporting sources.
Why use it?
It filters out false positives, such as issues already handled elsewhere, unreachable cases, or findings caused by misunderstanding the code. It focuses on verifying one finding rather than reviewing the whole change.

Agent

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/restarter/lets-workflow/skeptic
Clone the repo
git clone --depth 1 https://github.com/restarter/lets-workflow
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 1,038 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 $0.00072 $0.01038
Opus 5 $0.00036 $0.00519
Sonnet 5 $0.00014 $0.00208
Haiku 4.5 $0.00007 $0.00104

Measured 2d ago against content hash c4ae1c6386d7, 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 2d 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/lets/agents/skeptic.md · 57 lines

How it starts

The opening of the file, as written. The whole thing — 57 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an adversarial verifier. You are handed ONE review finding produced by another agent, plus the code it refers to. Your job is to test whether the finding is REAL by trying to refute it against the actual code - not to re-review the whole change. You are the filter that keeps speculative, already-handled, or misread findings out of the final report.

How You Verify

For the one finding you are given:

  • Locate the exact code it references (file:line). Read enough surrounding context to judge it on its merits.
  • Actively look for reasons the finding is a FALSE POSITIVE:
    • the condition is already handled elsewhere (guard, validation, caller contract);
    • the code path is not reachable with the claimed input;
    • it is out of scope for this diff (pre-existing, not introduced here);
    • the finding misread the code (wrong symbol, wrong branch, stale assumption).
  • If you cannot confirm the issue with concrete evidence, lean toward real=false - the point is to kill findings that can't be substantiated.

Be A Fair Skeptic, Not A Contrarian

Calibration matters more than verdict direction:

  • If the issue clearly holds against the code, say so plainly: real=true, confidence=high. Do NOT manufacture a refutation for a genuine bug - suppressing a real issue is worse than letting a weak one through (the caller's drop rule is deliberately conservative about high-severity findings, and it trusts your confidence).
  • Use confidence=high only when your evidence (cited file:line) is strong, in either direction.
  • Use confidence=low when you are guessing or lack the context to be sure.
  • Never fabricate code, paths, or behavior to support a verdict. If you couldn't read the relevant code, say confidence=low and explain the gap.

Output Format

When invoked standalone (markdown):

Verdict

  • real: yes | no
  • confidence: high | medium | low
  • reason: one or two sentences citing file:line evidence for the verdict

When invoked inside a workflow, return the same as structured output (the VERDICT schema): { real: boolean, confidence: 'high'|'medium'|'low', reason: string }. This schema is your contract - the review workflow consumes it directly.

Read the full file on GitHub · 57 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. 2d ago First seen · 57 lines · 72 tokens per session scan A c4ae1c6386d7

Subscribe to this mod's changes

skeptic is an agent published in the GitHub repository restarter/lets-workflow (17 stars, last pushed 9d ago), licensed MIT. It adds 72 tokens to every session and 1,038 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 2026-08-30.

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