001-no-hallucination

001-no-hallucination is a cursor rule for Cursor from bookedsolidtech/helixir. It costs 283 tokens per session, scanned A, original, MIT.

A set of rules that tells Claude not to make up APIs, packages, file paths, code, or test results.

In plain words
What is it for?
Use it to require checking source code or documentation before referring to APIs, libraries, files, or test outcomes.
Why use it?
It reduces errors caused by presenting unverified technical details as facts.

Cursor rule for Cursor

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 rules/bookedsolidtech/helixir/001-no-hallucination
Clone the repo
git clone --depth 1 https://github.com/bookedsolidtech/helixir

Made for: Cursor.

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 001-no-hallucination

README.md
[![agentmods](https://agentmods.dev/badge/rules/bookedsolidtech/helixir/001-no-hallucination.svg)](https://agentmods.dev/rules/bookedsolidtech/helixir/001-no-hallucination)
Your own site
<a href="https://agentmods.dev/rules/bookedsolidtech/helixir/001-no-hallucination"><img src="https://agentmods.dev/badge/rules/bookedsolidtech/helixir/001-no-hallucination.svg" alt="Measured on agentmods" height="20"></a>
Per session 283 This file is loaded in full into every session.
When invoked 283 The same file — it is already loaded in full.
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 $0.00283 $0.00283
Opus 5 $0.00142 $0.00142
Sonnet 5 $0.00057 $0.00057
Haiku 4.5 $0.00028 $0.00028

Measured 5d ago against content hash 0565c874faa5, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

001-no-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 5d 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

.cursor/rules/001-no-hallucination.mdc · 29 lines

What it actually says

No Hallucination

"I'm not sure" is always better than guessing.

Rules

  1. Never invent APIs or function signatures. If you haven't read the source or docs, say so. Do not guess method names, parameter shapes, or return types.

  2. Never invent file paths. Before referencing a file path, verify it exists. Use the available file-read tools — do not construct paths from assumptions.

  3. Never invent package names. If you're not certain a package exists on the registry, say so. Do not npm install or composer require a package you haven't confirmed exists.

  4. Never invent test results. If you haven't run the tests, do not claim they pass. Run them first.

  5. Prefer "I need to check X" over confident-but-wrong statements. Uncertainty stated explicitly is a recoverable state. Confident fabrication causes downstream rework.

When to apply

  • Before referencing any external API or library method
  • Before writing import statements for unfamiliar packages
  • Before asserting that a file, function, or type exists
  • Before claiming tests pass or build succeeds without running them
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. 5d ago First seen · 29 lines · 283 tokens per session scan A 0565c874faa5

Subscribe to this mod's changes

001-no-hallucination is a cursor rule published in the GitHub repository bookedsolidtech/helixir (5 stars, last pushed 2mo ago), licensed MIT. It adds 283 tokens to every session, about $0.0014 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.