vizro: Instructions file for Claude Code

CLAUDE.md

vizro CLAUDE.md is an instructions file for Claude Code from mckinsey/vizro. It costs 496 tokens per session, scanned A, original, Apache-2.0.

A set of development instructions for Vizro, a Python project for building dashboards, spread across several related packages in one repository. It explains the project layout, setup, and common Hatch commands.

In plain words
What is it for?
Use it when setting up Vizro, choosing the right package directory, or running common development commands with Hatch.
Why use it?
It helps an agent work in the correct package and follow the repository's development process without guessing how the project is organized.

Instructions file for Claude Code

Written for Claude Code: the file is CLAUDE.md. Also seen: mentions Claude Code.

This is mckinsey/vizro's own configuration. It tells Claude Code how to work on vizro itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything vizro configures →

About the project

Vizro is an open-source Python toolkit for assembling data visualization applications from low-code configuration. It helps developers create dashboards and multi-page apps from charts, tables, controls, layouts, navigation, and interactions, with optional high-code customization. Catalogue add-ons support working with Vizro projects.

mckinsey/vizro · 3,789 stars · on GitHub · vizro.readthedocs.io

Reuse

Borrowing it

Nothing to install: this file belongs to mckinsey/vizro. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/mckinsey/vizro/main/CLAUDE.md
Clone the repo
git clone --depth 1 https://github.com/mckinsey/vizro

Made for: Claude Code.

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README.md
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Per session 496 This file is loaded in full into every session.
When invoked 496 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00496 $0.00496
Opus 5 $0.00248 $0.00248
Sonnet 5 $0.00099 $0.00099
Haiku 4.5 $0.00050 $0.00050

Measured 8d ago against content hash cb1c3acd5427, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

vizro CLAUDE.md 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.

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.

CLAUDE.md · 45 lines

How it starts

The opening of the file, as written. The whole thing — 45 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Vizro Development Guide for AI Agents

This is a monorepo containing multiple Vizro packages. The main packages are:

  • vizro-core/: The core Vizro dashboard framework
  • vizro-ai/: Framework for AI-assisted dashboard development
  • vizro-mcp/: Model Context Protocol server for AI-assisted dashboard development
  • vizro-dash-components/: Custom Dash components maintained by Vizro (TypeScript/React → Python).
  • vizro-e2e-flow/: (Anthropic) Claude Code plugin with skills for end-to-end dashboard development (no hatch commands)
  • vizro-experimental/: The incubation home for Vizro features that aren't ready for vizro-core. APIs in this package may change or be removed between releases. Once a feature is ready, it graduates to vizro-core.

Development Setup (across all packages)

Only Dependency: Hatch

Vizro uses Hatch as its only direct development dependency. You don't need to manually install Python or create virtual environments - Hatch handles this automatically. If not installed, guide the user on how to install it.

Working Directory

Navigate to the specific package directory (e.g., cd vizro-core) before running Hatch commands.

Common Hatch Commands across all packages

Run these from within the package directory (e.g., vizro-core/):

  • hatch run python -c "xxx" - Run a Python command
  • hatch run pypath - Show Python interpreter path
  • hatch run lint - Check and fix code quality/formatting
  • hatch run changelog:add - Generate changelog fragment (required for PRs)
  • hatch run test-unit - Run test suite
  • hatch run docs:serve - Build and serve documentation (hot-reloads)

Development Flow

  1. Make changes to code
  2. Run hatch run lint to check formatting
  3. Run hatch run test-unit to verify tests pass (you can add --last-failed to rerun only failures from the last test run)
  4. Run hatch run changelog:add to create changelog fragment

Key configuration files

  • pyproject.toml: Main tooling configuration for the monorepo

Read the full file on GitHub · 45 lines

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 · 45 lines · 496 tokens per session scan A cb1c3acd5427

Subscribe to this mod's changes

vizro CLAUDE.md is an instructions file published in the GitHub repository mckinsey/vizro (3,789 stars, last pushed today), licensed Apache-2.0. It adds 496 tokens to every session, about $0.0025 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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