building-a-threat-hunt-hypothesis

building-a-threat-hunt-hypothesis is a skill for Claude Code, Codex from meltedinhex/analyst-ai-pack. It costs 67 tokens per session (818 once invoked), scanned A, original, Apache-2.0.

A structured plan for threat hunting, where defenders proactively search their systems for signs of an attacker instead of waiting for an alert.

In plain words
What is it for?
Use it to define a behavior-based hypothesis, map it to available logs such as EDR, Sysmon, DNS, proxy, or authentication data, and determine whether the result is a detection, a telemetry gap, or a confident negative.
Why use it?
It turns a vague security concern into a testable statement with required data, detection logic, success criteria, and a clear outcome.

Skill for Claude CodeCodex

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

Good fit Use it to define a behavior-based hypothesis, map it to available logs such as EDR, Sysmon, DNS, proxy, or authentication data, and determine whether the result is a detection, a telemetry gap, or a confident negative.

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Install with agentmods
npx agentmods add skills/meltedinhex/analyst-ai-pack/building-a-threat-hunt-hypothesis
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 meltedinhex/analyst-ai-pack --skill building-a-threat-hunt-hypothesis
Clone the repo
git clone --depth 1 https://github.com/meltedinhex/analyst-ai-pack

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 building-a-threat-hunt-hypothesis

README.md
[![agentmods](https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/building-a-threat-hunt-hypothesis/github.svg)](https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/building-a-threat-hunt-hypothesis)
Your own site
<a href="https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/building-a-threat-hunt-hypothesis"><img src="https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/building-a-threat-hunt-hypothesis/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 building-a-threat-hunt-hypothesis

Your own site · 80×15
<a href="https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/building-a-threat-hunt-hypothesis"><img src="https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/building-a-threat-hunt-hypothesis.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 67 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 818 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 $0.00067 $0.00818
Opus 5 $0.00034 $0.00409
Sonnet 5 $0.00013 $0.00164
Haiku 4.5 $0.00007 $0.00082

Measured 11d ago against content hash 51925ee94803, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

building-a-threat-hunt-hypothesis 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.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/analyst.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/building-a-threat-hunt-hypothesis/SKILL.md · 97 lines

How it starts

The opening of the file, as written. The whole thing — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Building a Threat-Hunt Hypothesis

When to Use

  • You are starting a proactive, hypothesis-driven hunt rather than responding to an alert.
  • You need to turn a vague concern ("are we seeing living-off-the-land abuse?") into a testable, scoped statement with clear data requirements.
  • You want a repeatable plan that produces either a detection, a gap, or a confident negative.

Do not use this as an incident-response trigger — if you already have a confirmed alert, pivot to investigation/IR, not hypothesis generation.

Prerequisites

  • Knowledge of your environment's telemetry (EDR, Sysmon, proxy, DNS, auth logs) and retention.
  • Familiarity with ATT&CK to anchor the behavior you intend to hunt.

Workflow

Step 1: Pick a behavior, not a tool

Anchor on an adversary behavior (an ATT&CK technique/sub-technique) you have reason to expect given your threat model, not a specific product alert.

Step 2: Write a testable hypothesis

Use the form: "If [actor behavior], then I expect to observe [evidence] in [data source]."

If an adversary uses WMI for lateral movement (T1047), then I expect to observe
wmiprvse.exe spawning command interpreters on hosts that do not normally do so,
in Sysmon process-creation (Event ID 1).

Step 3: Map to data and logic

Confirm the data source exists and is retained, then define the concrete query/detection logic and what "normal" looks like (baseline) so anomalies stand out.

python scripts/analyst.py plan --technique T1047 --datasource "Sysmon EID1" --window 14d

Step 4: Set scope and success criteria

Define the host/time scope, the threshold for "interesting," and the three possible outcomes: finding (→ IR), detection gap (→ engineering), or confident negative (documented).

Step 5: Record and hand off

Capture the hypothesis, queries, and outcome so it becomes a repeatable, version-controlled hunt — successful logic becomes a detection rule.

Validation

  • The hypothesis is falsifiable and names a specific data source that actually exists.
  • A baseline of "normal" is defined so results are interpretable.
  • Each outcome has a defined next action (IR, detection engineering, or documented negative).

Read the full file on GitHub · 97 lines

Files

What ships with it

3 files 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. 11d ago First seen · 97 lines · 67 tokens per session scan A 51925ee94803

Subscribe to this mod's changes

building-a-threat-hunt-hypothesis is a skill published in the GitHub repository meltedinhex/analyst-ai-pack (22 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 67 tokens to every session and 818 once invoked, about $0.0003 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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