anti-hallucination

anti-hallucination is a skill for Claude Code from a-ariff/ariff-claude-plugins. It costs 39 tokens per session (683 once invoked), scanned A, original, MIT.

A method for reducing AI hallucinations, meaning answers that present made-up or unverified information as fact.

In plain words
What is it for?
It is for accuracy-critical work where responses need verification, citations, and clear limits on what is known.
Why use it?
It makes the assistant check evidence, support claims, and openly state when something is uncertain.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the anti-hallucination plugin — 1 skill shipped together

Good fit It is for accuracy-critical work where responses need verification, citations, and clear limits on what is known.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/a-ariff/ariff-claude-plugins/anti-hallucination
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.

Any agent
npx skills add a-ariff/ariff-claude-plugins --skill anti-hallucination
Clone the repo
git clone --depth 1 https://github.com/a-ariff/ariff-claude-plugins

Made for: Claude Code.

Or install anti-hallucination, the plugin that ships this one along with the rest of its 1 skill.

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 anti-hallucination

README.md
[![agentmods](https://agentmods.dev/badge/skills/a-ariff/ariff-claude-plugins/anti-hallucination/github.svg)](https://agentmods.dev/skills/a-ariff/ariff-claude-plugins/anti-hallucination)
Your own site
<a href="https://agentmods.dev/skills/a-ariff/ariff-claude-plugins/anti-hallucination"><img src="https://agentmods.dev/badge/skills/a-ariff/ariff-claude-plugins/anti-hallucination/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 anti-hallucination

Your own site · 80×15
<a href="https://agentmods.dev/skills/a-ariff/ariff-claude-plugins/anti-hallucination"><img src="https://agentmods.dev/badge/skills/a-ariff/ariff-claude-plugins/anti-hallucination.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 39 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 683 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 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 5.1 $0.00039 $0.00683
Opus 5 $0.00019 $0.00342
Sonnet 5 $0.00008 $0.00137
Haiku 4.5 $0.00004 $0.00068

Measured 11d ago against content hash d792cbfe3605, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

anti-hallucination 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 11d 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/anti-hallucination/skills/anti-hallucination/SKILL.md · 84 lines

How it starts

The opening of the file, as written. The whole thing — 84 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Anti-Hallucination Methodology

A systematic approach to ensuring every response is grounded in verifiable facts.

Core principle

Never state something as fact unless you have verified it with your tools. If you cannot verify, say so explicitly.

The verification hierarchy

Before making any factual claim, follow this hierarchy:

Level 1: Direct evidence (strongest)

You read the actual file and saw the code. "The function validateToken at src/auth.ts:42 returns false when the token is expired."

Level 2: Search evidence

You searched and found matching results. "Grep found 3 references to validateToken across the codebase."

Level 3: Inference from evidence

You didn't find the exact thing but can reasonably infer from what you found. "Based on the error handling pattern in src/auth.ts, expired tokens likely return a 401 status." (Mark this as inference.)

Level 4: General knowledge

You know this from training data but haven't verified it in this codebase. "Express middleware typically calls next() to pass control." (Mark this as general knowledge, not specific to this project.)

Level 5: Uncertainty

You don't know and haven't checked. "I'm not sure how this handles token refresh. Let me check." (Then actually check.)

Hallucination patterns to avoid

Invented file paths

Wrong: "The config is at src/config/database.ts" Right: Use Glob to find it first, then reference the actual path.

Assumed function signatures

Wrong: "The function takes a userId and returns a Promise" Right: Read the file and quote the actual signature.

Phantom dependencies

Wrong: "Since you're using lodash..." Right: Check package.json first.

Memory-based version numbers

Wrong: "React 18.2 introduced this feature" Right: Check the actual installed version in package.json.

Confident wrong answers

Wrong: "This will definitely fix the issue" Right: "Based on the error pattern, this should fix the issue. Let's verify after applying."

Phrases to use

Read the full file on GitHub · 84 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. 11d ago First seen · 84 lines · 39 tokens per session scan A d792cbfe3605

Subscribe to this mod's changes

anti-hallucination is a skill published in the GitHub repository a-ariff/ariff-claude-plugins (14 stars, last pushed 5mo ago), licensed MIT. It adds 39 tokens to every session and 683 once invoked, about $0.0002 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.