pharmacophore

pharmacophore is a skill for Claude Code from Kdevos12/ALKYL. It costs 91 tokens per session (946 once invoked), scanned A, original, MIT.

A guide to pharmacophore modeling, which describes the chemical features and 3D arrangement a molecule needs to interact with a biological target. It covers features such as hydrogen-bond donors, acceptors, aromatic rings, hydrophobic regions, and charged groups.

In plain words
What is it for?
Use it to derive models from protein–ligand structures or active molecules, screen compound libraries, calculate pharmacophore fingerprints, find alternative molecular scaffolds, and compare binding hypotheses with activity data.
Why use it?
Molecules can look different as 2D structures while presenting similar features in three dimensions. Modeling those shared features helps search for related compounds and test ideas about how they bind.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the alkyl plugin — 27 skills shipped together

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/kdevos12/alkyl/pharmacophore
Any agent
npx skills add Kdevos12/ALKYL --skill pharmacophore
Clone the repo
git clone --depth 1 https://github.com/Kdevos12/ALKYL

Made for: Claude Code.

Or install alkyl, the plugin that ships this one along with the rest of its 27 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 pharmacophore

README.md
[![agentmods](https://agentmods.dev/badge/skills/kdevos12/alkyl/pharmacophore.svg)](https://agentmods.dev/skills/kdevos12/alkyl/pharmacophore)
Your own site
<a href="https://agentmods.dev/skills/kdevos12/alkyl/pharmacophore"><img src="https://agentmods.dev/badge/skills/kdevos12/alkyl/pharmacophore.svg" alt="Measured on agentmods" height="20"></a>
Per session 91 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 946 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 $0.00091 $0.00946
Opus 5 $0.00046 $0.00473
Sonnet 5 $0.00018 $0.00189
Haiku 4.5 $0.00009 $0.00095

Measured 6d ago against content hash 60d0a0f2b9ca, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

pharmacophore 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.

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.

skills/pharmacophore/SKILL.md · 78 lines

How it starts

The opening of the file, as written. The whole thing — 78 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Pharmacophore Modeling

A pharmacophore defines the minimum set of 3D chemical features — their types, spatial arrangement, and tolerance spheres — required for biological activity. Used for scaffold hopping, virtual screening, and SAR hypothesis generation.

When to Use This Skill

  • Derive pharmacophore from a co-crystal structure (structure-based)
  • Extract common features from a set of active ligands (ligand-based)
  • Screen a compound library for pharmacophore matches (VS)
  • Compute pharmacophore fingerprints for similarity searching
  • Identify scaffold-hopping opportunities (2D-diverse but 3D-similar)
  • Validate binding mode hypotheses against active/inactive SAR data

Feature Types

Feature Code SMARTS definition (simplified)
H-bond donor HBD [N!H0,O!H0,n!H0]
H-bond acceptor HBA [N,O,F,n,o,s] (lone pairs)
Aromatic AR any aromatic ring
Hydrophobic HYD [c,s,C,S,Br,I,Cl] non-polar
Positive ionizable POS [NH2,NH3+,guanidine,amidine]
Negative ionizable NEG [COOH,SO3H,PO4H,COO-]
Exclusion volume XV regions sterically forbidden

Quick Start

from rdkit import Chem
from rdkit.Chem import AllChem, MolStandardize
from rdkit.Chem.Pharm3D import Pharmacophore, EmbedLib
from rdkit.Chem import rdMolChemicalFeatures

# Load feature factory (FDEF file bundled with RDKit)
import os
from rdkit import RDConfig
fdefName = os.path.join(RDConfig.RDDataDir, 'BaseFeatures.fdef')
factory = rdMolChemicalFeatures.BuildFeatureFactory(fdefName)

# Get features from a molecule
mol = Chem.MolFromSmiles('c1ccc(cc1)C(=O)O')  # benzoic acid
feats = factory.GetFeaturesForMol(mol)
for feat in feats:
    print(f"{feat.GetFamily():12s} {feat.GetType():20s} atoms={list(feat.GetAtomIds())}")

Router — What to Read

Task Reference
Feature types, SMARTS, exclusion volumes, RDKit FDEF format references/features-theory.md
Pharm2D fingerprints (Gobbi), Pharm3D matching, feature factory references/rdkit-pharmacophore.md
Derive pharmacophore from protein-ligand co-crystal / interactions references/structure-based.md
Common-feature pharmacophore from a set of active ligands references/ligand-based.md
Pharmacophore VS workflow: conformer gen, hit scoring, enrichment references/vs-workflow.md

Read the full file on GitHub · 78 lines

Files

What ships with it

5 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 · 78 lines · 91 tokens per session scan A 60d0a0f2b9ca

Subscribe to this mod's changes

pharmacophore is a skill published in the GitHub repository Kdevos12/ALKYL (6 stars, last pushed 5mo ago), licensed MIT. It adds 91 tokens to every session and 946 once invoked, about $0.0005 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 2026-08-31.

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