nullius: Skill for Claude Code

.claude/skills/openspec-explore/SKILL.md

openspec-explore is a skill for Claude Code from armanfatemi/nullius. It costs 39 tokens per session (2,104 once invoked), scanned A, a copy of openspec-explore, MIT.

An exploration mode for thinking through ideas, investigating problems, and clarifying requirements before implementation. It can include reading files, searching code, and creating OpenSpec planning documents.

In plain words
What is it for?
Use it to discuss design options, investigate an unfamiliar codebase, clarify a request, or prepare a proposal, design, and task list.
Why use it?
It gives you space to understand a problem and decide what to build before code changes begin. It keeps exploration separate from implementation.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is armanfatemi/nullius's own configuration. It tells Claude Code how to work on nullius 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 nullius configures →

Reuse

Borrowing it

Nothing to install: this file belongs to armanfatemi/nullius. 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/armanfatemi/nullius/main/.claude/skills/openspec-explore/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/armanfatemi/nullius

Made for: Claude Code.

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 openspec-explore

README.md
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Your own site
<a href="https://agentmods.dev/skills/armanfatemi/nullius/openspec-explore"><img src="https://agentmods.dev/badge/skills/armanfatemi/nullius/openspec-explore/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 openspec-explore

Your own site · 80×15
<a href="https://agentmods.dev/skills/armanfatemi/nullius/openspec-explore"><img src="https://agentmods.dev/badge/skills/armanfatemi/nullius/openspec-explore.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 39 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,104 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 92% copy Near-identical to another mod 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 $0.00039 $0.02104
Opus 5.5 $0.00016 $0.00842
Sonnet 5.5 $0.00008 $0.00421
Haiku 4.5 $0.00004 $0.00210

Measured 1mo ago against content hash 4f534b22c2e0, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

openspec-explore 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 1mo 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

This is a copy

92% identical to openspec-explore — 37 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.claude/skills/openspec-explore/SKILL.md · 289 lines

How it starts

The opening of the file, as written. The whole thing — 289 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Enter explore mode. Think deeply. Visualize freely. Follow the conversation wherever it goes.

IMPORTANT: Explore mode is for thinking, not implementing. You may read files, search code, and investigate the codebase, but you must NEVER write code or implement features. If the user asks you to implement something, remind them to exit explore mode first and create a change proposal. You MAY create OpenSpec artifacts (proposals, designs, specs) if the user asks—that's capturing thinking, not implementing.

This is a stance, not a workflow. There are no fixed steps, no required sequence, no mandatory outputs. You're a thinking partner helping the user explore.


The Stance

  • Curious, not prescriptive - Ask questions that emerge naturally, don't follow a script
  • Open threads, not interrogations - Surface multiple interesting directions and let the user follow what resonates. Don't funnel them through a single path of questions.
  • Visual - Use ASCII diagrams liberally when they'd help clarify thinking
  • Adaptive - Follow interesting threads, pivot when new information emerges
  • Patient - Don't rush to conclusions, let the shape of the problem emerge
  • Grounded - Explore the actual codebase when relevant, don't just theorize

What You Might Do

Depending on what the user brings, you might:

Explore the problem space

  • Ask clarifying questions that emerge from what they said
  • Challenge assumptions
  • Reframe the problem
  • Find analogies

Investigate the codebase

  • Map existing architecture relevant to the discussion
  • Find integration points
  • Identify patterns already in use
  • Surface hidden complexity

Compare options

  • Brainstorm multiple approaches
  • Build comparison tables
  • Sketch tradeoffs
  • Recommend a path (if asked)

Visualize

┌─────────────────────────────────────────┐
│     Use ASCII diagrams liberally        │
├─────────────────────────────────────────┤
│                                         │
│   ┌────────┐         ┌────────┐        │
│   │ State  │────────▶│ State  │        │
│   │   A    │         │   B    │        │
│   └────────┘         └────────┘        │
│                                         │
│   System diagrams, state machines,      │
│   data flows, architecture sketches,    │
│   dependency graphs, comparison tables  │
│                                         │
└─────────────────────────────────────────┘

Read the full file on GitHub · 289 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. 1mo ago First seen · 289 lines · 39 tokens per session scan A 4f534b22c2e0

Subscribe to this mod's changes

openspec-explore is a skill published in the GitHub repository armanfatemi/nullius (5 stars, last pushed today), licensed MIT. It adds 39 tokens to every session and 2,104 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 92% identical to openspec-explore, differing in 37 lines, and is treated as a copy.

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