chem-spectrum-matcher

chem-spectrum-matcher is a skill for Claude Code, Codex from learningmatter-mit/AtomisticSkills. It costs 52 tokens per session (2,519 once invoked), scanned A, original, MIT.

A tool for comparing experimental chemical spectra, such as NMR or infrared measurements, with predicted or database spectra for possible molecules. NMR measures how atomic nuclei respond to a magnetic field, while infrared spectroscopy measures how molecules absorb infrared light.

In plain words
What is it for?
Use it to check a proposed chemical structure, rank a shortlist of candidates, or retrieve reference spectra before running new predictions.
Why use it?
It helps rank candidate molecules by spectral similarity and avoids repeating expensive predictions when matching spectra are already cached or available in public databases.

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/chem-spectrum-matcher
Any agent
npx skills add learningmatter-mit/AtomisticSkills --skill chem-spectrum-matcher
Clone the repo
git clone --depth 1 https://github.com/learningmatter-mit/AtomisticSkills

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 chem-spectrum-matcher

README.md
[![agentmods](https://agentmods.dev/badge/skills/learningmatter-mit/atomisticskills/chem-spectrum-matcher.svg)](https://agentmods.dev/skills/learningmatter-mit/atomisticskills/chem-spectrum-matcher)
Your own site
<a href="https://agentmods.dev/skills/learningmatter-mit/atomisticskills/chem-spectrum-matcher"><img src="https://agentmods.dev/badge/skills/learningmatter-mit/atomisticskills/chem-spectrum-matcher.svg" alt="Measured on agentmods" height="20"></a>
Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,519 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00052 $0.02519
Opus 5 $0.00026 $0.01260
Sonnet 5 $0.00010 $0.00504
Haiku 4.5 $0.00005 $0.00252

Measured 6d ago against content hash c19c58f6bbe3, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

chem-spectrum-matcher 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 6d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/match_spectrum.py, scripts/register_spectrum.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/chem-spectrum-matcher/SKILL.md · 231 lines

How it starts

The opening of the file, as written. The whole thing — 231 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Spectrum Matcher

Goal

To retrieve or generate reference spectra for a set of candidate molecules and rank them by similarity to an experimental query spectrum. The skill abstracts a common three-component pattern:

  1. Prediction — generate reference spectra from structure (SMILES) via empirical predictors or QM.
  2. Reference DB — cache computed spectra locally; fall back to public databases for known compounds.
  3. Similarity metric — score each candidate against the query and rank.

This pattern applies to any spectral modality: 1H NMR, 13C NMR, IR, mass spectrometry, UV-Vis, Raman. The concrete implementation here covers 1H NMR and IR, with the NMR path fully implemented and IR sketched for extension.

When to Use This Skill

  • Confirm a proposed structure against an experimental spectrum.
  • Screen a shortlist of candidates and rank by spectral similarity.
  • Avoid re-running expensive predictions by retrieving cached spectra from the local catalog.
  • Fetch experimental reference spectra from public databases (NMRShiftDB2, NIST WebBook) before committing to a prediction run.

When NOT to Use This Skill

  • Unknown structure elucidation from scratch — this skill requires a candidate list. For open-ended structure identification, use general-query-literature-database first.
  • Mixture deconvolution — use chem-nmr-analysis (Wasserstein deconvolution) for quantifying component ratios.
  • 13C, 19F, 31P NMR predictionchem-nmr-predict (SPINUS) covers 1H only. Extension needed.
  • Mass spectrometry — not yet implemented. Scaffold is in place; add a predictor and similarity metric.

Architecture

SMILES  ──► [Predictor]  ──► predicted spectrum (.xy / .jdx)
                                        │
                                        ▼
                              [Local Catalog]  ◄──  register_spectrum.py
                                        │
        [Public DB fallback]  ──────────┤  (NMRShiftDB2, NIST WebBook)
                                        │
                                        ▼
            Experimental query  ──► [match_spectrum.py]  ──► ranked candidates

Read the full file on GitHub · 231 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. 6d ago First seen · 231 lines · 52 tokens per session scan A c19c58f6bbe3

Subscribe to this mod's changes

chem-spectrum-matcher is a skill published in the GitHub repository learningmatter-mit/AtomisticSkills (160 stars, last pushed 2d ago), licensed MIT. It adds 52 tokens to every session and 2,519 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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