nwis.streamflow.basin_conditions
Get real-time streamflow readings for all active USGS gauge stations within a HUC-8 watershed basin. Returns current discharge (ft3/s) at every station in the basin — typically 5–40 sites — in a single call. Ideal for watershed-scale flood monitoring, drought assessment, and basin hydrology surve...
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What nwis.streamflow.basin_conditions does on Apibase
AI agents call nwis.streamflow.basin_conditions to retrieve information from Apibase without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
period | string | — | ISO 8601 duration for how recent the data should be (e.g. "PT2H" = last 2 hours, "PT6H" = last 6 hours). Default is "PT2H". Longer periods return more data but |
huc_code | string | Yes | USGS Hydrologic Unit Code (HUC) — 8-digit watershed code (e.g. "02070008" for the Potomac Basin). Use 8-digit HUC for best results. Find HUC codes at water.usgs |
Parameters from the server's own tool schema.
Why nwis.streamflow.basin_conditions is rated Low
Retrieves public USGS streamflow data with no side effects.
From the tool's definition Get real-time streamflow readings for all active USGS gauge stations
Attacks that exploit this kind of access
The rule that runs nwis.streamflow.basin_conditions safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Apibase, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For nwis.streamflow.basin_conditions, this is the rule to start with:
nwis.streamflow.basin_conditions is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Apibase, apply this rule, and every nwis.streamflow.basin_conditions call is checked against it from then on.
Questions about nwis.streamflow.basin_conditions
Get real-time streamflow readings for all active USGS gauge stations within a HUC-8 watershed basin. Returns current discharge (ft3/s) at every station in the basin — typically 5–40 sites — in a single call. Ideal for watershed-scale flood monitoring, drought assessment, and basin hydrology surveys. HUC-8 (8-digit Hydrologic Unit Code) defines a sub-basin level watershed (e.g. "02070008" = Potomac Basin). Find HUC codes at water.usgs.gov or use huc=XXXXXXXX for your area of interest. No auth — USGS public domain, updated every 15 minutes. It is categorised as a Read tool in the Apibase MCP Server, which means it retrieves data without modifying state.
nwis.streamflow.basin_conditions accepts 2 parameters: period, huc_code. Required: huc_code. The full parameter table on this page comes from the server's own tool schema.
Register the Apibase MCP server in PolicyLayer and add a rule for nwis.streamflow.basin_conditions: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Apibase. Nothing to install.
nwis.streamflow.basin_conditions is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the nwis.streamflow.basin_conditions rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for nwis.streamflow.basin_conditions. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
nwis.streamflow.basin_conditions is provided by the Apibase MCP server (apibase-mcp-client). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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