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NOAA Tides and Currents

by io.github.RyanCardin15
OverviewAdmin

Get Observed Water Levels

noaa_get_water_levels
Read-onlyIdempotent

Get observed water levels from a NOAA tide station as a time series.

Choose the interval: "6" = standard 6-minute observations (preliminary or verified, max 31 days per request), "1" = 1-minute preliminary data (max 4 days), "hourly" = verified hourly heights (max 1 year). Heights are relative to the requested datum (MLLW by default — the US nautical chart zero).

Returns per record: t (timestamp in requested time zone), v (height), s (sigma), f (quality flags, decoded in output), q (p=preliminary, v=verified). Recent data is preliminary; verification takes days to weeks.

Use for: "what is the water level right now" (date=latest), storm surge analysis, comparing observed vs predicted tide. Do NOT use for future tides — use noaa_get_tide_predictions.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
dateNoShortcut window: "today" = midnight to now, "latest" = single most recent reading, "recent" = last 72 hours. Mutually exclusive with begin_date/end_date/range.
datumNoVertical reference datum for heights. MLLW is the standard chart datum for coastal stations. IGLD and LWD apply to Great Lakes stations ONLY; NAVD/CRD exist only at stations where computed. Check a station's supported datums with noaa_get_station_datums.MLLW
rangeNoNumber of hours. With begin_date: hours forward. With end_date: hours back. Alone: hours back from now.
unitsNoUnit system. english: feet, °F, knots (wind AND currents), nautical miles. metric: meters, °C, m/s for wind but cm/s for currents, kilometers. Air pressure is millibars and salinity is PSU in BOTH systems.english
stationYesStation ID. Water-level/met stations use 7-digit numeric IDs (e.g. "9414290" San Francisco); current stations use alphanumeric IDs (e.g. "cb0102"). Find stations with noaa_search_stations or noaa_find_nearest_stations.
end_dateNoEnd date/time. Same formats as begin_date.
intervalNoObservation interval: "6" = 6-minute (standard, 31-day max), "1" = 1-minute preliminary (4-day max), "hourly" = verified hourly heights (1-year max).6
time_zoneNoTime zone for timestamps: gmt = UTC, lst = station local standard time (no DST), lst_ldt = station local time with DST. Note: daily_mean data requires lst.lst_ldt
begin_dateNoStart date/time. Formats: yyyyMMdd, "yyyyMMdd HH:mm", MM/dd/yyyy, or ISO yyyy-MM-dd[THH:mm].
response_formatNoOutput format: "markdown" for a readable summary table, "json" for the complete structured payload.markdown

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

  1. First observed

TDQS

A5/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate read-only, idempotent, non-destructive behavior. The description adds valuable context: data is preliminary until verified (takes days/weeks), intervals have max durations, heights are relative to a datum, and output fields are documented. No contradictions with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is well-structured: first sentence states purpose, then parameter details, then usage guidance. It is front-loaded with essential info, and every sentence adds value. No redundant or vague phrasing.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (10 parameters, no output schema), the description covers all key aspects: what is returned (per record fields), how to interpret data (preliminary vs verified), caveats, and alternatives. It is complete enough for an agent to select and invoke correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, but the description adds significant meaning beyond schema: explains interval types (standard vs preliminary), default datum (MLLW), unit system quirks (air pressure in both systems), and time zone details (daily_mean requires lst). This saves the agent from inferring these nuances.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool gets observed water levels from a NOAA tide station as a time series. It specifies the resource (water levels), action (get), and scope (observed). Sibling tools like noaa_get_tide_predictions are distinguished by noting the tool is not for future tides, providing clear differentiation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly lists use cases (current water level, storm surge analysis, comparing observed vs predicted) and explicitly states what not to use it for (future tides, directing to noaa_get_tide_predictions). It also explains interval constraints (max days per request) and datum behavior, giving comprehensive guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

All NOAA Tides and Currents toolsInspect
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