bio-scaffold-analysis

bio-scaffold-analysis is a skill for Claude Code, Codex from PKU-YuanGroup/OpenAI4S. It costs 97 tokens per session (3,960 once invoked), scanned A, a copy of bio-scaffold-analysis, MIT.

A chemistry workflow for grouping and comparing molecules by their scaffolds—the ring-and-linker framework left after variable substituents are removed. It includes scaffold decomposition, clustering, and analysis of structural changes across related compounds.

In plain words
What is it for?
Use it to cluster compounds by chemotype, assess library diversity, create scaffold-balanced machine-learning splits, analyse R-groups, and study scaffold hopping.
Why use it?
It helps reveal chemical series and library diversity while reducing misleading comparisons between different representations of the same underlying structure.

Skill for Claude CodeCodex

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

Good fit Use it to cluster compounds by chemotype, assess library diversity, create scaffold-balanced machine-learning splits, analyse R-groups, and study scaffold hopping.

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Install with agentmods
npx agentmods add skills/pku-yuangroup/openai4s/bio-chemoinformatics-scaffold-analysis
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 PKU-YuanGroup/OpenAI4S --skill bio-chemoinformatics-scaffold-analysis
Clone the repo
git clone --depth 1 https://github.com/PKU-YuanGroup/OpenAI4S

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 bio-scaffold-analysis

README.md
[![agentmods](https://agentmods.dev/badge/skills/pku-yuangroup/openai4s/bio-chemoinformatics-scaffold-analysis/github.svg)](https://agentmods.dev/skills/pku-yuangroup/openai4s/bio-chemoinformatics-scaffold-analysis)
Your own site
<a href="https://agentmods.dev/skills/pku-yuangroup/openai4s/bio-chemoinformatics-scaffold-analysis"><img src="https://agentmods.dev/badge/skills/pku-yuangroup/openai4s/bio-chemoinformatics-scaffold-analysis/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 bio-scaffold-analysis

Your own site · 80×15
<a href="https://agentmods.dev/skills/pku-yuangroup/openai4s/bio-chemoinformatics-scaffold-analysis"><img src="https://agentmods.dev/badge/skills/pku-yuangroup/openai4s/bio-chemoinformatics-scaffold-analysis.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 97 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,960 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 91% 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 $0.00097 $0.03960
Opus 5 $0.00048 $0.01980
Sonnet 5 $0.00019 $0.00792
Haiku 4.5 $0.00010 $0.00396

Measured 8d ago against content hash 4d70f98677e2, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

bio-scaffold-analysis 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 8d ago.

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

Origin

This is a copy

91% identical to bio-scaffold-analysis — 12 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.

skills/bioskills/bio-chemoinformatics-scaffold-analysis/SKILL.md · 323 lines

How it starts

The opening of the file, as written. The whole thing — 323 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Version Compatibility

Reference examples tested with: RDKit 2024.09+, mmpdb 3.1+, scikit-learn 1.4+, datamol 0.12+.

Before using code patterns, verify installed versions match. If versions differ:

  • Python: pip show <package> then help(module.function) to check signatures

If code throws ImportError, AttributeError, or TypeError, introspect the installed package and adapt the example to match the actual API rather than retrying.

Scaffold Analysis

Analyze chemical libraries by their underlying scaffolds. Bemis-Murcko (1996) is the canonical scaffold decomposition: ring systems + linkers, with all R-groups stripped. Generic framework + cyclic skeleton are progressively-more-abstract views. Scaffold analysis underpins QSAR train/test splits (preventing data leakage), library diversity assessment, chemotype clustering, R-group decomposition for SAR modeling, and matched molecular pair analysis (MMPA). The choice of scaffold representation determines whether two compounds are "the same series" -- a critical decision for medicinal chemistry workflows.

For reaction-based enumeration and Free-Wilson, see chemoinformatics/reaction-enumeration. For scaffold-hopping via fingerprints, see chemoinformatics/similarity-searching. For 3D shape-based scaffold hopping, see chemoinformatics/shape-similarity.

Scaffold Representation Taxonomy

Representation Origin Definition Use case Fails when
Bemis-Murcko scaffold Bemis & Murcko 1996 Ring systems + linkers, R-groups stripped Default chemotype identifier Linear molecules (no rings) -> empty scaffold
Generic framework Bemis & Murcko 1996 Bemis-Murcko with all atoms set to C, all bonds single Topology comparison Loses heteroatom info
Cyclic skeleton (CSK) Custom RDKit transformation Ring atoms only, all C, all single Pure ring-topology view Loses linker info; not a built-in Murcko option
Murcko atom indices Derived by matching the scaffold to the parent Parent-molecule atom indices Programmatic operations Symmetry can yield multiple equivalent matches

Read the full file on GitHub · 323 lines

Files

What ships with it

2 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. 8d ago First seen · 323 lines · 97 tokens per session scan A 4d70f98677e2

Subscribe to this mod's changes

bio-scaffold-analysis is a skill published in the GitHub repository PKU-YuanGroup/OpenAI4S (403 stars, last pushed yesterday), licensed MIT. It adds 97 tokens to every session and 3,960 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. It is 91% identical to bio-scaffold-analysis, differing in 12 lines, and is treated as a copy.

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