What is cozi_mcp CLAUDE.md?

Repository instructions for Cozi Family Organizer, a service for managing family lists and calendars. They describe its Node.js and TypeScript codebase, available development commands, packaging methods, and test setup.

Guiding work on the MCP server, its read and write operations, local development, automated tests, builds, and MCPB or Smithery distribution.

They give coding agents the project context and the commands needed to build, test, type-check, run, and package the service. They also document the migration from an older Python version.

How mjucius/cozi_mcp configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to mjucius/cozi_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/mjucius/cozi_mcp/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/mjucius/cozi_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

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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

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Per session 1,906 This file is loaded in full into every session.

When invoked 1,906 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	$0.01906	$0.01906
Opus 5	$0.00953	$0.00953
Sonnet 5	$0.00381	$0.00381
Haiku 4.5	$0.00191	$0.00191

Measured today against content hash 1eb0840f91ae, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

cozi_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 today.

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 · 105 lines

How it starts

The opening of the file, as written. The whole thing — 105 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.

Project Overview

Node 20+/TypeScript MCP server that exposes Cozi Family Organizer (lists + calendar) to AI assistants. Distributed three ways: MCPB bundle (drag-and-drop into Claude Desktop), Smithery cloud deployment, and npx @mjucius/cozi-mcp for power users.

v2.0 (2026-05) is a ground-up Node/TypeScript rewrite of the prior Python v1. The runtime changed AND the tool surface was consolidated (14 → 12 tools, slim projections). See README.md for the v1→v2 migration table. Legacy Python source is preserved at git tag v1.0.0.

Development Commands

npm install — install dependencies
npm test — vitest (136 tests, mocks CoziClient at the boundary; no creds needed)
npm run typecheck — tsc --noEmit
npm run build — tsup → dist/server.js + dist/bin.js
npm run dev — local stdio dev (needs COZI_USERNAME + COZI_PASSWORD env vars)
npm run playground — @smithery/cli local playground UI
npm run bundle:mcpb — produces cozi-mcp.mcpb at repo root

scripts/smoke.ts, scripts/smoke-write.ts and scripts/smoke-multiday.ts exercise read, write and multi-day/all-day paths against real Cozi (read creds from creds.env or env vars; each cleans up after itself). Useful sanity checks after changes to the HTTP / Cozi client layer.

Architecture

Core components

src/server.ts — createServer({ config }) factory. Smithery default export. Per-credentials Map<string, CoziClient> cache so concurrent sessions stay isolated.
src/bin.ts — npx + MCPB stdio entry point (#!/usr/bin/env node). Reads COZI_USERNAME/COZI_PASSWORD env vars, instantiates createServer, pipes to StdioServerTransport.
src/instructions.ts — SERVER_INSTRUCTIONS constant injected into the MCP server.
src/cozi/ — Inlined Cozi HTTP client. No separate npm package. Cozi API access lives here.
- client.ts — CoziClient class with 13 methods (auth + list/item/calendar CRUD).
- http.ts — fetch wrapper with per-client cookie jar, 100ms rate-limit gate, 3-attempt retry/backoff, 401-once-then-reauth.
- models.ts — Zod schemas with .transform() for camelCase↔snake_case wire mapping.
- appointment-payloads.ts — toApiCreate/Edit/DeleteFormat() builders for the three Cozi appointment payload shapes.
- errors.ts — CoziError hierarchy.
src/tools/ — 12 MCP tools. Each tool has a *Handler function (directly testable) and a register*Tool(server, getClient) registrar.
- projections.ts — slimPerson / slimListSummary / slimItem / slimAppt. Wire keys are exact strings (type, item_count, all_day — not listType, itemCount, allDay).
- parsers.ts — parseIsoDateTime, parseListType.

Read the full file on GitHub · 105 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.

today Changed · +2 lines · +232 tokens per session 1eb0840f91ae
9d ago First seen · 103 lines · 1,674 tokens per session scan A f1ee77ed8760

Subscribe to this mod's changes

cozi_mcp CLAUDE.md is an instructions file published in the GitHub repository mjucius/cozi_mcp (3 stars, last pushed today), licensed MIT. It adds 1,906 tokens to every session, about $0.0095 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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