Live tide data for AI assistants

Connect Your AI Assistant

Cal Coast Tides runs a free, read-only MCP server. Add it to your assistant and it can look up our tides, conditions, buoys, surf forecasts, fishing reports and guides instead of guessing. No account or key needed.

The server URL

https://www.calcoasttides.com/api/mcp

It speaks MCP over Streamable HTTP, with no sign-in. Paste it wherever your assistant asks for a custom connector or remote MCP server.

Claude (web, desktop and mobile)

  1. Open Settings, then Connectors.
  2. Choose Add custom connector.
  3. Name it Cal Coast Tides, paste the URL above and save. There is nothing to sign in to.
  4. In a chat, turn the connector on from the tools menu and ask away.

Free plans allow one custom connector. Anthropic's guide: custom connectors.

Claude Code

claude mcp add --transport http cal-coast-tides https://www.calcoasttides.com/api/mcp

Then ask in any session. Claude Code MCP docs.

ChatGPT

  1. In Settings, find Developer mode (under Apps & Connectors, Advanced settings) and turn it on.
  2. Create a new connector, name it Cal Coast Tides and paste the URL above.
  3. Choose no authentication, save, and enable it in a chat.

Custom connectors depend on your ChatGPT plan, and OpenAI moves these menus often. If yours look different, search OpenAI’s help center for “developer mode”.

Cursor, VS Code and other tools

In Cursor, add this to .cursor/mcp.json in your project (or ~/.cursor/mcp.json for every project):

{
  "mcpServers": {
    "cal-coast-tides": {
      "url": "https://www.calcoasttides.com/api/mcp"
    }
  }
}

Any other client that supports remote MCP servers over HTTP works the same way: give it the URL. Cursor MCP docs.

Things to ask

  • “When is the next low tide at Pismo Beach, and is it a minus tide?”
  • “Plan a tidepool morning near Pacific Grove in the next two weeks.”
  • “Is it worth surfing Morro Rock tomorrow? What does the buoy say?”
  • “How has Lopez Lake been fishing this month?”
  • “What does MLLW mean, and why was the water higher than predicted?”

Two ready-made starters show up in clients that support prompts: Plan a tidepool day and Surf check.

What it can look up (17 tools)

list_stationsThe 17 NOAA tide stations Cal Coast Tides covers on the California coast, north to south, with id, name, area, coordinates and site pages.
find_nearestGiven a latitude and longitude on the California coast, returns the nearest NOAA tide stations, offshore wave buoys and named surf spots with distance in miles and direction.
get_tidesPredicted high and low tides from NOAA for one station, from now through the next 1 to 14 days.
tide_nowWhether the tide at a station is rising or falling right now and the next two turns, as one plain-English sentence plus structured fields (Pacific local date and time, feet above MLLW).
tide_calendarA day-by-day tide calendar for up to 14 days from today (Pacific time): each day's highs and lows, lowest and highest water, spring or neap (from the day's tidal swing against the station's range), moon phases, minus tides and sunrise/sunset, plus "heads-up" notes such as highs above MHHW.
plan_tidepoolsLow tides at or below a height (default 1 ft above MLLW) over the next days, tagged by light: GO (daylight), GOLDEN (under 1.5 h before sunset), TWILIGHT (within 30 min of sunrise or sunset) or DARK.
get_conditionsThe Cal Coast Tides console for one station as JSON: tide level and direction with the next two turns, water level measured against the prediction (residual), swell height, period and direction, wind and gusts in knots, sea and water temperature, air, sky and rain chance, today's sunrise and sunset, and ratings (GREAT, GOOD, FAIR, POOR) for surf, tidepooling, harbor and kayak, and fishing, each with its reason and best window in the next 48 h.
list_buoysThe 25 NOAA NDBC and CDIP wave buoys off California, north to south, with id, name, coordinates and NDBC page.
get_buoyThe latest measured reading at one offshore buoy: significant wave height in feet, dominant period, wave direction, wind and gusts in knots, water temperature, each with its measurement time, plus whether waves are building, easing or steady over 3 h and how the last 6 h compare with the forecast model at the buoy.
swell_arrivalWhether a long-period northwest swell seen at buoys up the coast is on the way to a station, and the window when it usually arrives, from the measured travel time between buoys (checked against past swells).
list_surf_spotsThe named surf spots Cal Coast Tides forecasts (San Luis Obispo County so far), with id, region, break type, level, which way the beach faces, offshore wind direction, its tide station and page.
surf_forecastSurf at one named spot now and for up to 7 days: estimated wave face height range in feet, a rating (FLAT, POOR, FAIR, GOOD, GREAT) with reasons, wind relative to the beach (offshore, cross, onshore), swell, tide, and for each day the best daylight window and a confidence (range for days 0 to 3, wide for days 4 to 7, trend beyond).
search_siteSearch the whole site: Journal guides, explainers and fishing reports, Tide School lessons, travel guides and tide stations.
get_postOne Journal post in full: title, date, type (guide, explainer or field report), activities, regions, its tide station, the "before you head out" facts, and the Markdown body (long posts are cut at 15,000 characters).
fishing_reportsSan Luis Obispo County fishing reports with their per-place verdicts (good, fair or rough), newest first, for a date range (default: the last 30 days, at most a year), optionally for one place such as "Lopez Lake", "Lake Nacimiento" or "Morro Bay offshore".
explainPlain-language explanations from the site's Tide School and glossary: a term such as MLLW, MHHW, MSL, minus tide, slack, residual or swell period returns its definition; a topic such as "reading tide tables", "where tide data comes from", "mixed semidiurnal tides", "tide datums" or "predictions vs reality" returns the full lesson with its short answer and key facts.
get_destinationOne of the site's 28 California coast travel guides: its summary, top pick, the places it covers and the guide text (cut at 4,000 characters).

Fair use and fine print

  • Everything is read-only. The server can't change anything, send messages or see your account.
  • Each address can make 300 calls a minute. Answers are cached for up to an hour, so asking again is cheap.
  • Tides and water levels come from NOAA, buoys from NOAA's National Data Buoy Center, and swell, wind and weather from Open-Meteo (weather data by Open-Meteo.com).
  • Every answer carries the same notice the site does: this is not an official forecast, warning or navigation service. See the terms and disclaimer.

Tool names and fields are kept stable; anything that changes gets a note in the tool's description first. Questions or ideas? Get in touch.

Send feedback