drift-verify

drift-verify is an agent for Claude Code from yacb2/aidex. It costs 43 tokens per session (264 once invoked), scanned A, original, MIT.

A read-only checking tool that compares stated facts about a codebase with the files and lines cited for them. It returns whether each fact is confirmed, contradicted, or not verifiable.

In plain words
What is it for?
It is for checking evidence-backed lists of claims against source code without changing files.
Why use it?
It prevents reviews from treating comments, old notes, or unsupported claims as proof of current code behavior.

Agent for Claude Code

Written for Claude Code: effort in frontmatter. Also seen: model in frontmatter.

Part of the aidex plugin — 22 skills, 35 agents, 5 hooks shipped together

Good fit It is for checking evidence-backed lists of claims against source code without changing files.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/yacb2/aidex/drift-verify
View source ↗ yacb2/aidex
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/yacb2/aidex

Made for: Claude Code.

Or install aidex, the plugin that ships this one along with the rest of its 22 skills, 35 agents, 5 hooks.

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 drift-verify

README.md
[![agentmods](https://agentmods.dev/badge/agents/yacb2/aidex/drift-verify/github.svg)](https://agentmods.dev/agents/yacb2/aidex/drift-verify)
Your own site
<a href="https://agentmods.dev/agents/yacb2/aidex/drift-verify"><img src="https://agentmods.dev/badge/agents/yacb2/aidex/drift-verify/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 drift-verify

Your own site · 80×15
<a href="https://agentmods.dev/agents/yacb2/aidex/drift-verify"><img src="https://agentmods.dev/badge/agents/yacb2/aidex/drift-verify.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 43 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 264 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 $0.00043 $0.00264
Opus 5.5 $0.00017 $0.00106
Sonnet 5.5 $0.00009 $0.00053
Haiku 4.5 $0.00004 $0.00026

Measured 6d ago against content hash ab51bbe34f06, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

drift-verify 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 6d 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.

agents/drift-verify.md · 16 lines

What it actually says

You are a refuter. You receive numbered facts about a code base, each citing a file and lines. You do not know who wrote them.

  • Open the cited lines for every fact. confirmed only if the code says it, now. refuted if the code says otherwise; state what it says. unverifiable if the cited place does not settle it and a short search does not either.
  • Burden of proof is inverted: when unsure, it is not confirmed.
  • Rules from skills/reference/references/01-discovery.md: a negative needs a consumer search you ran yourself (Rule 3); a claimed capability needs an entry point that reaches it (Rule 3'); a comment or a changelog is not evidence of current behavior (Rule 5).
  • One verdict per fact index, none skipped. evidence names the file and symbol you checked.
  • Never write files.
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. 6d ago First seen · 16 lines · 43 tokens per session scan A ab51bbe34f06

Subscribe to this mod's changes

drift-verify is an agent published in the GitHub repository yacb2/aidex (2 stars, last pushed yesterday), licensed MIT. It adds 43 tokens to every session and 264 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-10-11.