What is chronos-mcp CLAUDE.md?

Project instructions for Chronos MCP, a Python server that connects AI tools to CalDAV calendars, which are calendars that can be accessed by compatible services. They cover installation, running the server, formatting, linting, type checks, tests, and the layered code structure.

Use it when developing the Chronos MCP server, running unit or integration tests, checking coverage, formatting Python code, or reviewing its architecture. It also lists commands for starting the server and cleaning build files.

They give contributors the commands and project conventions needed to develop and verify changes safely. This avoids inconsistent formatting and missed checks before commits.

How democratize-technology/chronos-mcp configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to democratize-technology/chronos-mcp. 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/democratize-technology/chronos-mcp/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/democratize-technology/chronos-mcp

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/democratize-technology/chronos-mcp/claude-md/github.svg)](https://agentmods.dev/instructions/democratize-technology/chronos-mcp/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/democratize-technology/chronos-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/democratize-technology/chronos-mcp/claude-md/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/democratize-technology/chronos-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/democratize-technology/chronos-mcp/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,075 This file is loaded in full into every session.

When invoked 1,075 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.

Model	Per session	Once invoked
Fable 5.1	$0.01075	$0.01075
Opus 5.5	$0.00430	$0.00430
Sonnet 5.5	$0.00215	$0.00215
Haiku 4.5	$0.00108	$0.00108

Measured 2mo ago against content hash cea723fcdbc7, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

chronos-mcp 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 2mo 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 · 142 lines

How it starts

The opening of the file, as written. The whole thing — 142 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Core Commands

Development

# Install for development with all dependencies
make dev-install

# Run the MCP server
./run_chronos.sh
# or
python -m chronos_mcp

# Format code (required before committing)
make format

# Run linting checks
make lint

# Run all tests
make test

# Run specific test categories
make test-unit         # Unit tests only
make test-integration  # Integration tests only

# Run tests with coverage
make coverage

# Run a single test file
pytest tests/unit/test_events.py -v

# Run a specific test
pytest tests/unit/test_events.py::test_create_event -v

# Clean build artifacts
make clean

Linting and Formatting

# Format with black and isort
black chronos_mcp tests
isort chronos_mcp tests

# Check formatting without modifying
black --check chronos_mcp tests
isort --check-only chronos_mcp tests

# Type checking
mypy chronos_mcp

Architecture Overview

Chronos MCP is a Model Context Protocol server for CalDAV calendar management built with FastMCP 2.0. The codebase follows a layered architecture:

Key Components

MCP Interface Layer (server.py)
- Defines MCP tools using FastMCP decorators
- Handles input validation and error sanitization
- Maps tool calls to business logic managers
Tool Interface Layer (tools/)
- tools/base.py: Base tool manager class with connection caching
- tools/accounts.py: Account management tools
- tools/calendars.py: Calendar CRUD tools
- tools/events.py: Event lifecycle tools
- tools/tasks.py: VTODO task tools
- tools/journals.py: VJOURNAL journal tools
- tools/bulk.py: Bulk operation tools
- Delegation pattern: server.py delegates to tools/, tools/ delegate to business logic managers
Business Logic Layer
- accounts.py: Multi-account management with connection caching
- calendars.py: Calendar CRUD operations
- events.py: Event lifecycle including recurring events (RRULE)
- tasks.py: VTODO task management
- journals.py: VJOURNAL journal entry management
- bulk.py: Parallel bulk operations with rollback support
- search.py: Advanced search with relevance ranking

Read the full file on GitHub · 142 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.

2mo ago First seen · 142 lines · 1,075 tokens per session scan A cea723fcdbc7

Subscribe to this mod's changes

chronos-mcp CLAUDE.md is an instructions file published in the GitHub repository democratize-technology/chronos-mcp (31 stars, last pushed 6d ago), licensed MIT. It adds 1,075 tokens to every session, about $0.0043 per session on Opus 5.5. 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.

Backend and APIs Building agents

chronos-mcp CLAUDE.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
chronos-mcp CLAUDE.mddemocratize-technology/chronos-mcp	Instructions file	31	6d ago	MIT	A	1,075	Claude Code
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	yesterday	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness	Instructions file	274k	2d ago	MIT	A	4,313	Codex, OpenCode

chronos-mcp: Instructions file for Claude Code