anthropics/financial-services · error · ImportError

openpyxl not installed. Run: pip install openpyxl

Error message

openpyxl not installed. Run: pip install openpyxl

What it means

Raised in DCFModelValidator.__init__ when the Python interpreter cannot import openpyxl, the library used to read Excel workbooks (both formulas and cached values). The validator deliberately converts the ImportError into a friendlier message with install instructions. It is an environment problem, not a model or code problem.

Source

Thrown at plugins/agent-plugins/model-builder/skills/dcf-model/scripts/validate_dcf.py:20

"""
DCF Model Validation Script
Validates Excel DCF models for formula errors and common DCF mistakes
"""

import sys
import json
from pathlib import Path
from typing import Optional


class DCFModelValidator:
    """Validates DCF models for errors and quality issues"""

    def __init__(self, excel_path: str):
        try:
            import openpyxl
        except ImportError:
            raise ImportError("openpyxl not installed. Run: pip install openpyxl")

        self.excel_path = excel_path
        self.openpyxl = openpyxl

        if not Path(excel_path).exists():
            raise FileNotFoundError(f"File not found: {excel_path}")

        self.workbook_formulas = openpyxl.load_workbook(excel_path, data_only=False)
        self.workbook_values = openpyxl.load_workbook(excel_path, data_only=True)
        self.errors = []
        self.warnings = []
        self.info = []
        
    def validate_all(self) -> dict:
        """
        Run all validation checks

        Returns:

View on GitHub (pinned to 69cbc81467)

Solutions

1. Install into the same interpreter you run the script with: python -m pip install openpyxl
2. If the repo has a requirements file (e.g. skills/dcf-model/scripts/requirements.txt), install it: python -m pip install -r requirements.txt
3. Verify the right environment: which python && python -c 'import openpyxl; print(openpyxl.__version__)' before re-running validate_dcf.py
4. For skill/agent bundles, add openpyxl to the environment setup documented in the skill's SKILL.md so runtimes provisioning the skill install it

Example fix

# before
python scripts/validate_dcf.py model.xlsx
# ImportError: openpyxl not installed. Run: pip install openpyxl

# after
python -m pip install openpyxl
python scripts/validate_dcf.py model.xlsx

import importlib.util
if importlib.util.find_spec('openpyxl') is None:
    raise SystemExit('openpyxl missing: python -m pip install openpyxl')

def has_openpyxl() -> bool:
    return importlib.util.find_spec('openpyxl') is not None

try:
    validator = DCFModelValidator(path)
except ImportError as e:
    raise SystemExit(f'Dependency error: {e}. Install with: python -m pip install openpyxl')

When it happens

Trigger: Instantiating DCFModelValidator(excel_path) in an environment where openpyxl is not installed, e.g. running validate_dcf.py with the system Python instead of the project venv, or after a fresh clone without installing requirements. The try: import openpyxl at the top of __init__ fails and re-raises ImportError with this message.

Common situations: Running the skill script in a CI container, agent sandbox, or managed runtime that has a minimal Python install; mixing Python versions (installed into 3.11 but running 3.12); using a conda env without the package; pip install succeeding for a different interpreter (pip vs pip3 vs python -m pip).

Related errors

• openpyxl not installed. Run: pip install openpyxl
• openpyxl not installed. Run: pip install openpyxl
• File not found: {excel_path}
• File not found: {excel_path}
• File not found: {excel_path}

AI-assisted analysis of anthropics/financial-services@69cbc81467 (2026-08-27). Data as JSON: /api/errors/4e959d4c1cc9db6d. Report an issue: GitHub.