antithesis-research

antithesis-research is a skill for Claude Code from antithesishq/antithesis-skills. It costs 49 tokens per session (3,350 once invoked), scanned A, original, Apache-2.0.

A codebase-analysis guide for planning Antithesis tests. It examines the system's architecture, state, concurrency, and likely failure points, then records testable properties.

In plain words
What is it for?
Use it to map the system, identify important behaviours to test, plan the container setup, document evidence, and record relationships between possible failures.
Why use it?
It turns an unfamiliar system into a concrete testing plan before test workloads and deployment setup are created.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions subagents.

Part of the antithesis-skills plugin — 12 skills shipped together

Good fit Use it to map the system, identify important behaviours to test, plan the container setup, document evidence, and record relationships between possible failures.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/antithesishq/antithesis-skills/antithesis-research
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 antithesishq/antithesis-skills --skill antithesis-research
Clone the repo
git clone --depth 1 https://github.com/antithesishq/antithesis-skills

Made for: Claude Code.

Or install antithesis-skills, the plugin that ships this one along with the rest of its 12 skills.

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 antithesis-research

README.md
[![agentmods](https://agentmods.dev/badge/skills/antithesishq/antithesis-skills/antithesis-research/github.svg)](https://agentmods.dev/skills/antithesishq/antithesis-skills/antithesis-research)
Your own site
<a href="https://agentmods.dev/skills/antithesishq/antithesis-skills/antithesis-research"><img src="https://agentmods.dev/badge/skills/antithesishq/antithesis-skills/antithesis-research/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 antithesis-research

Your own site · 80×15
<a href="https://agentmods.dev/skills/antithesishq/antithesis-skills/antithesis-research"><img src="https://agentmods.dev/badge/skills/antithesishq/antithesis-skills/antithesis-research.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,350 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
  • Socket pass 16 May 2026
  • Snyk warn 16 May 2026
  • NVIDIA SkillSpector pass 7 Sept 2026
SkillSpector: 1 finding, up to low

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 →

  • low Excessive Agency · line 34
    Skill's behavior or capabilities extend beyond its stated purpose. Scope creep allows an agent to perform actions unrelated to its documented functionality, increasing the attack surface.
    Fix: Limit the skill's scope to its documented purpose. Remove instructions that enable the agent to perform actions outside its stated functionality.
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 $0.00049 $0.03350
Opus 5 $0.00024 $0.01675
Sonnet 5 $0.00010 $0.00670
Haiku 4.5 $0.00005 $0.00335

Measured 3d ago against content hash 976a35a3741b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

antithesis-research 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 3d 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.

antithesis-research/SKILL.md · 188 lines

How it starts

The opening of the file, as written. The whole thing — 188 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Antithesis Research

Skill version: 2026-09-08 2e4a837

Purpose and Goal

Research a target system and produce scratchbook artifacts that unblock the rest of the workflow. Success means:

  • antithesis/scratchbook/sut-analysis.md captures architecture, state, concurrency, and failure-prone areas
  • antithesis/scratchbook/property-catalog.md lists concrete, testable properties with priorities
  • antithesis/scratchbook/deployment-topology.md describes the minimal useful container topology
  • antithesis/scratchbook/properties/{slug}.md captures per-property evidence trails and context
  • antithesis/scratchbook/property-relationships.md maps suspected clusters and connections between properties
  • antithesis/scratchbook/evaluation/synthesis.md records categorized evaluation findings and actions taken

Prerequisites and Scoping

At the start of every research run, ask the user about external references:

Before I start, are there docs, design notes, related repos, issue trackers, or anything else outside this directory tree that I should also consult? "Just this directory" is fine.

Capture the answer verbatim. Each external reference becomes a path (or URL) plus a brief why note. The orchestrator (this skill) holds the answer for the full duration of the run and threads it as input to every reference workflow that produces a top-level artifact: sut-discovery.md, sut-analysis.md, property-discovery.md, deployment-topology.md, property-evaluation.md. Each of those references' agent-instruction sections accepts the list as input. The list is also recorded in the provenance frontmatter of every top-level artifact (see references/scratchbook-setup.md). Any agent that receives the external references treats each as a lead to validate, not a fact — see references/validating-claims.md.

Beyond the scope question, ask only for blockers or scoping decisions you cannot infer safely:

  • The repo or codebase location, if it is not already clear
  • Which subsystem or component matters most, if the work is narrower than the whole repo
  • Known incidents, closed bugs, or specific failure modes worth targeting

Read the full file on GitHub · 188 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. 3d ago Changed 976a35a3741b
  2. 8d ago Changed 4397970ac422
  3. 12d ago First seen · 188 lines · 49 tokens per session scan A 1d8e1bc190c3

Subscribe to this mod's changes

antithesis-research is a skill published in the GitHub repository antithesishq/antithesis-skills (267 stars, last pushed 3d ago), licensed Apache-2.0. It adds 49 tokens to every session and 3,350 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.