security-investigator: Skill for Claude Code

.github/skills/scope-drift-detection/user/SKILL.md

scope-drift-detection-user is a skill for Claude Code, Codex from SCStelz/security-investigator. It costs 152 tokens per session (13,183 once invoked), scanned A, original, MIT.

A security analysis guide for finding gradual changes in an Entra ID user account's sign-ins, accessed resources, devices, locations, and settings.

In plain words
What is it for?
It helps compare current activity with the account's normal pattern, including new applications, resources, devices, IP addresses, locations, failures, and related security events.
Why use it?
It helps spot slow expansion of account activity that may not trigger alerts designed for sudden compromises.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

This is SCStelz/security-investigator's own configuration. It tells Claude Code and Codex how to work on security-investigator itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything security-investigator configures →

Reuse

Borrowing it

Nothing to install: this file belongs to SCStelz/security-investigator. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/SCStelz/security-investigator/main/.github/skills/scope-drift-detection/user/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/SCStelz/security-investigator

Made for: Claude Code, Codex.

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 scope-drift-detection-user

README.md
[![agentmods](https://agentmods.dev/badge/skills/scstelz/security-investigator/user/github.svg)](https://agentmods.dev/skills/scstelz/security-investigator/user)
Your own site
<a href="https://agentmods.dev/skills/scstelz/security-investigator/user"><img src="https://agentmods.dev/badge/skills/scstelz/security-investigator/user/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 scope-drift-detection-user

Your own site · 80×15
<a href="https://agentmods.dev/skills/scstelz/security-investigator/user"><img src="https://agentmods.dev/badge/skills/scstelz/security-investigator/user.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 152 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 13,183 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 2 findings, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Excessive Agency · line 114
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
  • medium Agent Snooping · line 974
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
How audits are shown
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 $0.00152 $0.13183
Opus 5 $0.00076 $0.06592
Sonnet 5 $0.00030 $0.02637
Haiku 4.5 $0.00015 $0.01318

Measured 9d ago against content hash d09bab33ba7c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

scope-drift-detection-user 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 9d 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.

.github/skills/scope-drift-detection/user/SKILL.md · 980 lines

How it starts

The opening of the file, as written. The whole thing — 980 lines — stays where its author put it; the contents beside it link to each section on GitHub.

User Account Scope Drift Detection — Instructions

Purpose

This skill detects scope drift — the gradual, often imperceptible expansion of access or behavior beyond an established baseline — in Entra ID user accounts. Unlike sudden compromise (which triggers alerts), scope drift is a slow-burn pattern that evades threshold-based detections.

Entity Type: User Account

Identifier Primary Table(s) Use Case
UserPrincipalName (UPN) SigninLogs + AADNonInteractiveUserSignInLogs Human users, admin accounts, shared mailboxes

What this skill detects:

  • Volume spikes in sign-in activity relative to historical baseline
  • New applications accessed (potential unauthorized access or shadow IT)
  • New target resources (APIs, services) not previously accessed
  • New device/OS/browser combinations
  • New source IP addresses or geographic locations
  • Increased failure rates indicating probing or misconfiguration
  • Account configuration changes correlated with behavioral shifts
  • Security alerts involving the user
  • Identity Protection risk events
  • Pre-computed sign-in anomalies (custom table)
  • Cloud app activity drift — new action types, admin operations, impersonation, external user activity (CloudAppEvents)
  • Email pattern drift — volume/direction changes, new sender domains, threat email trends (EmailEvents)

Related skills:


📑 TABLE OF CONTENTS

  1. Critical Workflow Rules - Start here!
  2. Output Modes - Inline chat vs. Markdown file
  3. Quick Start - 7-step investigation pattern
  4. Drift Score Formula - Weighted composite scoring (Interactive: 7 dimensions, Non-Interactive: 6 dimensions)
  5. Execution Workflow - Complete 4-phase process
  6. Sample KQL Queries - Validated query patterns (Queries 6-13)
  7. Report Template - Output format specification
  8. Known Pitfalls - Edge cases and false positives
  9. Error Handling - Troubleshooting guide
  10. SVG Dashboard Generation - Visual dashboard from report

Read the full file on GitHub · 980 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 9d ago First seen · 980 lines · 152 tokens per session scan A d09bab33ba7c

Subscribe to this mod's changes

scope-drift-detection-user is a skill published in the GitHub repository SCStelz/security-investigator (244 stars, last pushed yesterday), licensed MIT. It adds 152 tokens to every session and 13,183 once invoked, about $0.0008 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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