Usgs Volcano

List Volcanoes

list_volcanoes

Read-onlyIdempotent

List every US volcano monitored by USGS with current alert level (Normal/Advisory/Watch/Warning) and aviation color code (Green/Yellow/Orange/Red). Filter optionally by observatory.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`observatory`	No	Observatory short code (AVO=Alaska, CVO=Cascades, YVO=Yellowstone, HVO=Hawaiian, CalVO=California). Optional.

Output Schema

TableJSON Schema

Name	Required	Description
`total`	Yes	Total number of US volcanoes monitored
`returned`	Yes	Number of volcanoes returned after filtering
`volcanoes`	Yes	List of volcano records

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedMay 22, 2026

addedInput schema / examples

Added value: +[
+  {},
+  {
+    "observatory": "AVO"
+  }
+]

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "returned": {
+      "description": "Number of volcanoes returned after filtering",
+      "type": "number"
+    },
+    "total": {
+      "description": "Total number of US volcanoes monitored",
+      "type": "number"
+    },
+    "volcanoes": {
+      "description": "List of volcano records",
+      "items": {
+        "properties": {
+          "alert_level": {
+            "description": "Current alert level (Normal/Advisory/Watch/Warning)",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "alert_message": {
+            "description": "Current alert status message",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "alert_url": {
+            "description": "URL to full alert information",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "color_code": {
+            "description": "Aviation color code (Green/Yellow/Orange/Red)",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "elevation_m": {
+            "description": "Elevation in meters",
+            "type": [
+              "number",
+              "null"
+            ]
+          },
+          "latitude": {
+            "description": "Volcano latitude",
+            "type": [
+              "number",
+              "null"
+            ]
+          },
+          "longitude": {
+            "description": "Volcano longitude",
+            "type": [
+              "number",
+              "null"
+            ]
+          },
+          "modified": {
+            "description": "Last modification timestamp",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "name": {
+            "description": "Volcano name",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "observatory": {
+            "description": "Observatory code (AVO, CVO, HVO, etc.)",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "slug": {
+            "description": "USGS volcano slug for URLs",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "synonyms": {
+            "description": "Alternative volcano names",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "vnum": {
+            "description": "USGS volcano number",
+            "type": [
+              "string",
+              "null"
+            ]
+          }
+        },
+        "type": "object"
+      },
+      "type": "array"
+    }
+  },
+  "required": [
+    "total",
+    "returned",
+    "volcanoes"
+  ],
+  "type": "object"
+}

First observedMay 12, 2026

TDQS

A4.1/5.0

Behavior4/5

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

Annotations already indicate read-only, idempotent, and non-destructive behavior. The description adds value by specifying the exact scope ('every US volcano monitored by USGS') and the data fields returned, giving the agent useful behavioral context beyond the 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?

Two succinct sentences: the first conveys the core purpose and output, the second the optional filter. No redundant words, and key information is front-loaded, achieving excellent conciseness.

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 simple tool (1 optional param, full schema, comprehensive annotations, and an output schema), the description covers the scope, filter, and returned data adequately. Nothing essential is missing for agent invocation.

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

Parameters3/5

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

Schema coverage is 100%, so the schema fully documents the 'observatory' parameter. The description merely restates the filter option without adding new details, meeting the baseline but not exceeding it.

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 action ('List'), the resource ('every US volcano monitored by USGS'), and the specific data included (alert level and aviation color code). It also mentions the optional filter, making the tool's purpose precise and distinguishable from unrelated sibling tools.

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

Usage Guidelines3/5

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

The description explains what the tool does but provides no guidance on when to use it versus alternatives. While siblings are in different domains, the description does not explicitly state usage context or exclusions, limiting its helpfulness for selection.

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

All Usgs Volcano tools Inspect

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