mat-random-structure-search

mat-random-structure-search is a skill for Claude Code, Codex from learningmatter-mit/AtomisticSkills. It costs 31 tokens per session (1,037 once invoked), scanned A, original, MIT.

Generate random crystal structures for a given composition (AIRSS-style) and relax with MLIPs to find low-energy candidates.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/learningmatter-mit/atomisticskills/mat-random-structure-search
Any agent
npx skills add learningmatter-mit/AtomisticSkills --skill mat-random-structure-search
Clone the repo
git clone --depth 1 https://github.com/learningmatter-mit/AtomisticSkills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

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agentmods badge for mat-random-structure-search

README.md
[![agentmods](https://agentmods.dev/badge/skills/learningmatter-mit/atomisticskills/mat-random-structure-search.svg)](https://agentmods.dev/skills/learningmatter-mit/atomisticskills/mat-random-structure-search)
Your own site
<a href="https://agentmods.dev/skills/learningmatter-mit/atomisticskills/mat-random-structure-search"><img src="https://agentmods.dev/badge/skills/learningmatter-mit/atomisticskills/mat-random-structure-search.svg" alt="Measured on agentmods" height="20"></a>
Per session 31 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,037 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown 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 $0.00031 $0.01037
Opus 5 $0.00015 $0.00518
Sonnet 5 $0.00006 $0.00207
Haiku 4.5 $0.00003 $0.00104

Measured today against content hash 17ce8dd5c9af, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

mat-random-structure-search 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 today.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/generate_random_structures.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.

.agents/skills/mat-random-structure-search/SKILL.md · 95 lines

How it starts

The opening of the file, as written. The whole thing — 95 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Random Structure Search (AIRSS-Style)

Goal

To perform random structure searching (RSS) for a given chemical composition — the approach pioneered by AIRSS (Ab Initio Random Structure Searching, Pickard & Needs 2011). Random crystal structures are generated with sensible geometric constraints, then relaxed with an MLIP to identify low-energy candidates.

[!TIP] This method is complementary to ionic substitution and generative models like MatterGen and DiffCSP++. RSS explores the full potential energy surface without structural bias.

Instructions

  1. Generate random structures for the target composition:

    # Env: base-agent
    python .agents/skills/mat-random-structure-search/scripts/generate_random_structures.py \
        --composition NaCl \
        --num_structures 100 \
        --output_dir random_NaCl/
    

    The script will:

    • Sample random space groups from a list of common inorganic crystal space groups
    • Generate random lattice parameters consistent with each crystal system
    • Place atoms at random fractional coordinates
    • Filter structures for minimum interatomic distances
    • Save CIF files and a generation_manifest.json

    Optional parameters:

    • --spacegroups 225,166,62,14 — restrict to specific space groups
    • --volume_min 0.6 --volume_max 1.8 — control volume randomization range
    • --seed 42 — set random seed for reproducibility
  2. Relax all structures with an MLIP:

    mcp_mace_relax_structure(
        structure_data="random_NaCl/",
        relax_cell=True,
        fmax=0.02,
        steps=500,
        output_dir="relaxed_NaCl/"
    )
    

    Or with MatGL/FairChem — use the same MLIP consistently.

  3. Rank by energy: The lowest-energy relaxed structures are the most promising candidates. Check for duplicate structures using pymatgen's StructureMatcher.

  4. Validate top candidates: Compute stability (E_hull) for the best candidates to assess thermodynamic viability.

Read the full file on GitHub · 95 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. today First seen · 95 lines · 31 tokens per session scan A 17ce8dd5c9af

Subscribe to this mod's changes

mat-random-structure-search is a skill published in the GitHub repository learningmatter-mit/AtomisticSkills (158 stars, last pushed yesterday), licensed MIT. It adds 31 tokens to every session and 1,037 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 2026-09-03.

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