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MoleculeSimilarity (cal_molecule_similarity)

Molecule Molecular Information RDKit SMILES Molecular Operations
Table of Contents
Version: 0.1.0 Last Update: 2025/06/05 MCP Support Python Calling Support
Get the Tanimoto similarity of two molecules. It Can also be used to check if two molecules are identical.

Example 2

Input:

smiles1: 'CCO'
smiles2: 'C(O)C'

Text Input (used for the run_text function in the Python calling mode):

smiles_pair: 'CCO;C(O)C'

Output:

'Input Molecules Are Identical'

Usage

The tool supports both MCP mode and Python calling mode.

MCP Mode

Configure your MCP client following its instructions with something like:

{
    "command": "/ABSTRACT/PATH/TO/uv",  // Use `which uv` to get its path
    "args": ["--directory", "/ABSTRACT/PATH/TO/ChemMCP", "run", "--tools", "MoleculeSimilarity"],
    "toolCallTimeoutMillis": 300000,
    "env": {}
}

Python Calling Mode

import os
from chemmcp.tools import MoleculeSimilarity

# Initialize the tool
tool = MoleculeSimilarity()

# The tool has two alternative ways to run:
# 1. Run with separate input domains (recommended)
output = tool.run_code(
    smiles1='CCO'
    smiles2='CCN'
)
# 2. Run with text-only input
output = tool.run_text(
    smiles_pair='CCO;CCN'
)

Each tool in ChemMCP has two ways to run:

  • run_code (recommended): The inputs contain one or more domains, each of which can be a str, an int, a float, etc.
  • run_text: The inputs are a single string in a specific format. The tool will parse the string to extract the input domains. This is useful in scenarios where an agent framework calls tools only with text input. The output is the same in both cases.

For the input and output domains, please refer to the tool’s signature.

Tool Signature

Input

Used in the MCP mode, as well as the run_code function in the Python calling mode.

NameTypeDefaultDescription
smiles1strN/ASMILES string of the first molecule
smiles2strN/ASMILES string of the second molecule.

Text Input

Used in the run_text function in the Python calling mode.

NameTypeDefaultDescription
smiles_pairstrN/ASMILES strings of the two molecules, separated by a semicolon.

Output

The output is the same in both input cases.

NameTypeDescription
similaritystrTanimoto similarity score and similarity description

Envs

No required environment variables for this tool.

Implementation Details

  • Implementation Description: Uses the RDKit library to calculate the Tanimoto similarity of two molecules. Uses a text template to construct textual output.
  • Open-source dependencies (code source or required libraries):
  • Hosted services and software (required for running the tool): None