brew install shuntaka9576/tap/cal2prompt

git clone https://github.com/shuntaka9576/cal2prompt
cd cal2prompt
cargo install --path .

$ cal2prompt --help
✨ Fetches your schedule (e.g., from Google Calendar) and converts it into a single LLM prompt. It can also run as an MCP (Model Context Protocol) server.

Usage: cal2prompt [OPTIONS] [COMMAND]

Commands:
  mcp   Launch cal2prompt as an MCP server (experimental).
  help  Print this message or the help of the given subcommand(s)

Options:
      --since   Start date (YYYY-MM-DD). Requires --until.
      --until   End date (YYYY-MM-DD). Requires --since.
      --today         Fetch events for today only.
      --this-week     Fetch events for the current week (Mon-Sun).
      --this-month    Fetch events for the current month (1st - end).
      --next-week     Fetch events for the upcoming week (Mon-Sun).
  -h, --help          Print help
  -V, --version       Print version

local M = {}

M.google = {
  clientID = "***.apps.googleusercontent.com",
  clientSecret = "***",
  calendarIDs = {
    "example@gmail.com"
  },
}

return M

local cal2prompt = require("cal2prompt") -- builtin module
local os = require("os") -- stdlib
local secrets = require("secrets")

return {
  settings = {
    -- see https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
    -- TZ = "Etc/UTC",
    TZ = "Asia/Tokyo",
    -- TZ = "America/Los_Angeles"
    -- TZ - "Asia/Shanghai"
  },
  source = {
    google = {
      oauth2 = {
        clientID = secrets.google.clientID,
        clientSecret = secrets.google.clientSecret,
      },
      calendar = {
        getEvents = {
          calendarIDs = secrets.google.calendarIDs,
        },
      },
    },
  },
  output = {
    -- template = cal2prompt.template.google.standard
    template = [[
Here is your schedule summary. Please find the details below:
{% for day in days %}
## Date: {{ day.date }}
--------------------------------------

### All-Day Events:
{% if day.all_day_events|length == 0 %}
  (No all-day events)
{% else %}
  {% for ev in day.all_day_events %}
  - {{ ev.summary }}
    - (All Day)
    - Location: {{ ev.location or "N/A" }}
    - Description: {{ ev.description or "No description." }}
    - Attendees:
      {% if ev.attendees|length > 0 %}
        {% for a in ev.attendees %}
        - {{ a }}
        {% endfor %}
      {% else %}
      - (No attendees)
      {% endif %}
  {% endfor %}
{% endif %}

### Timed Events:
{% if day.timed_events|length == 0 %}
  (No timed events)
{% else %}
  {% for ev in day.timed_events %}
  - {{ ev.summary }}
    - Start: {{ ev.start }}
    - End:   {{ ev.end }}
    - Location: {{ ev.location or "N/A" }}
    - Description: {{ ev.description or "No description." }}
    - Attendees:
      {% if ev.attendees|length > 0 %}
        {% for a in ev.attendees %}
        - {{ a }}
        {% endfor %}
      {% else %}
      - (No attendees)
      {% endif %}
  {% endfor %}
{% endif %}
{% endfor %}
]],
  },
}

cal2prompt

{
  "mcpServers": {
    "cal2prompt": {
      "command": "/Users/username/.cargo/bin/cal2prompt",
      "args": ["mcp"],
      "env": {
        "HOME": "/Users/username"
      }
    }
  }
}