# noaa-tides

MCP server for [NOAA CO-OPS Tides and Currents](https://tidesandcurrents.noaa.gov/). Exposes tide predictions, observed water levels, and meteorological data from ~301 U.S. coastal stations as tools, resources, and prompts via [FastMCP 3.0](https://gofastmcp.com/).

Built for marine planning — fishing trips, boating, crabbing, safety checks.

## Install

```bash
# Run directly (no install needed)
uvx noaa-tides

# Or add to Claude Code
claude mcp add noaa-tides -- uvx noaa-tides

# Local development
uv run noaa-tides
```

## Tools

### `search_stations` — Find stations by name, state, or type

```
search_stations(state="WA")
```

Returns up to 50 matching stations:

```json
[
  {"id": "9447130", "name": "Seattle", "state": "WA", "lat": 47.6026, "lng": -122.3393, "tidal": true},
  {"id": "9446484", "name": "Tacoma", "state": "WA", "lat": 47.2671, "lng": -122.4132, "tidal": true},
  {"id": "9444900", "name": "Port Townsend", "state": "WA", "lat": 48.1129, "lng": -122.7595, "tidal": true}
]
```

Also supports `query` (name search) and `is_tidal` (filter tidal vs non-tidal).

### `find_nearest_stations` — Proximity search by coordinates

```
find_nearest_stations(latitude=47.6, longitude=-122.34, limit=3)
```

Distances in nautical miles:

```json
[
  {"id": "9447130", "name": "Seattle", "state": "WA", "lat": 47.6026, "lng": -122.3393, "distance_nm": 0.2},
  {"id": "9446484", "name": "Tacoma", "state": "WA", "lat": 47.2671, "lng": -122.4132, "distance_nm": 20.1},
  {"id": "9445958", "name": "Bremerton", "state": "WA", "lat": 47.5615, "lng": -122.6225, "distance_nm": 14.7}
]
```

### `get_station_info` — Expanded station metadata

```
get_station_info(station_id="9447130")
```

Returns sensors, datums, products, and station details. Seattle has been operating since 1899.

<details>
<summary>Full response (194 lines)</summary>

See [`examples/station-detail-seattle.json`](examples/station-detail-seattle.json)
</details>

### `get_tide_predictions` — High/low tide times

```
get_tide_predictions(station_id="9447130", hours=24)
```

Defaults to `hilo` interval (high/low times only) — the most useful format for planning:

```json
{
  "predictions": [
    {"t": "2026-02-21 00:49", "v": "2.658", "type": "L"},
    {"t": "2026-02-21 07:08", "v": "12.261", "type": "H"},
    {"t": "2026-02-21 13:43", "v": "1.167", "type": "L"},
    {"t": "2026-02-21 19:54", "v": "9.857", "type": "H"}
  ]
}
```

`type`: `H` = high tide, `L` = low tide. Values in feet above MLLW.

Other intervals: `"h"` (hourly), `"6"` (6-minute). Datum options: `MLLW`, `MSL`, `NAVD`, `STND`.

### `get_observed_water_levels` — Actual readings

```
get_observed_water_levels(station_id="9447130", hours=3)
```

6-minute interval observations. Compare with predictions to see how reality diverges:

```json
{
  "metadata": {"id": "9447130", "name": "Seattle", "lat": "47.6026", "lon": "-122.3393"},
  "data": [
    {"t": "2026-02-21 17:24", "v": "7.41", "s": "0.059", "f": "0,0,0,0", "q": "p"},
    {"t": "2026-02-21 17:30", "v": "7.62", "s": "0.072", "f": "0,0,0,0", "q": "p"},
    {"t": "2026-02-21 17:36", "v": "7.803", "s": "0.069", "f": "0,0,0,0", "q": "p"}
  ]
}
```

`q`: `"p"` = preliminary (real-time), `"v"` = verified (post-processed). `s` = standard deviation.

<details>
<summary>Full 3-hour response (213 lines)</summary>

See [`examples/water-levels-seattle.json`](examples/water-levels-seattle.json)
</details>

### `get_meteorological_data` — Weather observations

One tool, 8 products. Select via `product` parameter:

| Product | Fields | Units |
|---------|--------|-------|
| `air_temperature` | `v` | deg F |
| `water_temperature` | `v` | deg F |
| `wind` | `s` (speed), `d` (dir deg), `dr` (compass), `g` (gust) | knots |
| `air_pressure` | `v` | millibars |
| `conductivity` | `v` | mS/cm |
| `visibility` | `v` | nautical miles |
| `humidity` | `v` | percent |
| `salinity` | `v` | PSU |

```
get_meteorological_data(station_id="8454000", product="wind", hours=1)
```

```json
{
  "metadata": {"id": "8454000", "name": "Providence", "lat": "41.8072", "lon": "-71.4007"},
  "data": [
    {"t": "2026-02-21 22:24", "s": "2.72", "d": "109.0", "dr": "ESE", "g": "3.3", "f": "0,0"},
    {"t": "2026-02-21 22:30", "s": "3.3", "d": "103.0", "dr": "ESE", "g": "3.89", "f": "0,0"},
    {"t": "2026-02-21 22:36", "s": "2.72", "d": "108.0", "dr": "ESE", "g": "3.5", "f": "0,0"}
  ]
}
```

Not all stations support all products — use `get_station_info` to check available sensors.

### `marine_conditions_snapshot` — Everything at once

```
marine_conditions_snapshot(station_id="9447130")
```

Fires 6 parallel API calls (predictions, water level, water temp, air temp, wind, pressure) and returns a combined snapshot. Products that aren't available at a station appear under `unavailable` instead of failing the whole request:

```json
{
  "station_id": "9447130",
  "fetched_utc": "2026-02-22T04:15:38.291Z",
  "predictions": {"predictions": [{"t": "...", "v": "12.261", "type": "H"}, "..."]},
  "water_level": {"data": [{"t": "...", "v": "10.22", "s": "0.053", "f": "0,0,0,0", "q": "p"}, "..."]},
  "air_pressure": {"data": [{"t": "...", "v": "1012.4", "f": "0,0,0"}, "..."]},
  "unavailable": {
    "water_temperature": "ValueError: No data was found...",
    "air_temperature": "ValueError: No data was found...",
    "wind": "ValueError: No data was found..."
  }
}
```

Best starting point for trip planning or safety assessments.

## Resources

| URI | Description |
|-----|-------------|
| `noaa://stations` | Full station catalog (~301 stations) |
| `noaa://stations/{station_id}` | Expanded metadata for one station |
| `noaa://stations/{station_id}/nearby` | Stations within 50 nm |

## Prompts

### `plan_fishing_trip`

Guides the LLM through station discovery, tide analysis, and weather assessment to recommend optimal fishing windows.

```
plan_fishing_trip(location="Narragansett Bay", target_species="striped bass", date="20260615")
```

### `marine_safety_check`

GO / CAUTION / NO-GO assessment based on wind, visibility, water temperature, and pressure trends.

```
marine_safety_check(station_id="9447130")
```

## Response field reference

| Field | Meaning |
|-------|---------|
| `t` | Timestamp (local station time) |
| `v` | Value (water level ft, temp F, pressure mb, etc.) |
| `type` | `H` (high) or `L` (low) — predictions only |
| `s` | Speed (wind, knots) or sigma (water level, std deviation) |
| `d` | Wind direction in degrees true |
| `dr` | Wind compass direction (N, NE, SW, etc.) |
| `g` | Wind gust speed (knots) |
| `f` | Data quality flags (comma-separated) |
| `q` | QA level: `p` = preliminary, `v` = verified |

## Development

```bash
git clone <repo-url> && cd noaa-tides
uv sync --dev

# Run tests (13 tests, mock client, no network)
uv run pytest tests/ -v

# Lint
uv run ruff check src/

# Start server locally
uv run noaa-tides

# Headless test with Claude
claude -p "Search for tide stations in Rhode Island" \
  --mcp-config .mcp.json \
  --allowedTools "mcp__noaa-tides__*"
```

## Data source

All data from [NOAA Center for Operational Oceanographic Products and Services (CO-OPS)](https://tidesandcurrents.noaa.gov/). No API key required. Station IDs are 7-digit numbers (e.g. `9447130` for Seattle, `8454000` for Providence).

Two separate APIs are used:
- **Data API** — observations and predictions (`api.tidesandcurrents.noaa.gov/api/prod/datagetter`)
- **Metadata API** — station info, sensors, datums (`api.tidesandcurrents.noaa.gov/mdapi/prod/webapi`)

## License

MIT