Nasa Eonet

List Layers

list_layers

Read-onlyIdempotent

Visualization layer reference (mapping the events to imagery layers).

Input Schema

TableJSON Schema

Name	Required	Description	Default
`category`	No	Restrict to one category

Output Schema

TableJSON Schema

Name	Required	Description	Default
`link`	No
`title`	No
`categories`	No
`description`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed6 schema fields changedJun 2, 2026

addedOutput schema / properties / categories

Added value: +{
+  "items": {
+    "properties": {
+      "layers": {
+        "items": {
+          "properties": {
+            "name": {
+              "type": "string"
+            },
+            "parameters": {
+              "items": {
+                "properties": {
+                  "FORMAT": {
+                    "type": "string"
+                  },
+                  "TILEMATRIXSET": {
+                    "type": "string"
+                  }
+                },
+                "type": "object"
+              },
+              "type": "array"
+            },
+            "serviceTypeId": {
+              "type": "string"
+            },
+            "serviceUrl": {
+              "type": "string"
+            }
+          },
+          "type": "object"
+        },
+        "type": "array"
+      }
+    },
+    "type": "object"
+  },
+  "type": "array"
+}

addedOutput schema / properties / description
```
Added value: +{
+  "type": "string"
+}
```

removedOutput schema / properties / layers

Removed value: -{
-  "description": "Visualization layers for event mapping",
-  "items": {
-    "properties": {
-      "category": {
-        "description": "Associated category",
-        "type": "string"
-      },
-      "id": {
-        "description": "Layer id",
-        "type": "string"
-      },
-      "link": {
-        "description": "Layer link",
-        "type": "string"
-      },
-      "title": {
-        "description": "Layer title",
-        "type": "string"
-      }
-    },
-    "type": "object"
-  },
-  "type": "array"
-}

addedOutput schema / properties / link
```
Added value: +{
+  "type": "string"
+}
```
addedOutput schema / properties / title
```
Added value: +{
+  "type": "string"
+}
```
removedOutput schema / required
```
Removed value: -[
-  "layers"
-]
```

Changed2 schema fields changedMay 22, 2026

addedInput schema / examples

Added value: +[
+  {
+    "category": "wildfires"
+  }
+]

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "layers": {
+      "description": "Visualization layers for event mapping",
+      "items": {
+        "properties": {
+          "category": {
+            "description": "Associated category",
+            "type": "string"
+          },
+          "id": {
+            "description": "Layer id",
+            "type": "string"
+          },
+          "link": {
+            "description": "Layer link",
+            "type": "string"
+          },
+          "title": {
+            "description": "Layer title",
+            "type": "string"
+          }
+        },
+        "type": "object"
+      },
+      "type": "array"
+    }
+  },
+  "required": [
+    "layers"
+  ],
+  "type": "object"
+}

First observedMay 13, 2026

TDQS

C2.6/5.0

Behavior2/5

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, covering safety. The description adds the concept of 'mapping events to imagery layers' but does not disclose pagination, filtering behavior, or response format beyond the schema.

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

Conciseness4/5

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

The description is a single sentence—short and to the point. It is front-loaded and avoids wasted words, though it could be more informative.

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

Completeness2/5

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

Despite having an output schema and clear annotations, the description lacks detail on what the tool returns (e.g., layer names, IDs, mapping logic). It is incomplete for an AI agent to fully understand the tool's purpose and output.

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% with the 'category' parameter already described. The description does not add any extra meaning or examples for the parameter, so baseline score applies.

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

Purpose3/5

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

The description 'Visualization layer reference (mapping the events to imagery layers)' indicates the tool provides layers for visualizing events, but it uses a noun ('reference') instead of a clear verb+resource structure. It distinguishes from siblings like 'events' or 'list_categories' but not explicitly.

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

Usage Guidelines2/5

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

No guidance is provided on when to use this tool vs alternatives. Sibling tools exist (e.g., 'list_categories', 'events') but the description does not mention context or exclusions.

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

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