STAC MCP Server

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estimate_data_size

Estimate the data size for a STAC query before running it, helping you understand the volume of geospatial assets that match your spatial, temporal, and attribute filters.

Instructions

Estimate the data size for a STAC query.

Input Schema

TableJSON Schema

Name	Required	Default
`bbox`	No
`limit`	No
`query`	No
`datetime`	No
`aoi_geojson`	No
`catalog_url`	No
`collections`	Yes
`output_format`	No	text
`force_metadata_only`	No

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv6.3.0Aug 7, 2026
- addedInput schema / additionalProperties
```
Added value: +false
```

Changed37 schema fields changedv1.0.0Jan 3, 2026

addedInput schema / properties / aoi_geojson / anyOf

Added value: +[
+  {
+    "additionalProperties": true,
+    "type": "object"
+  },
+  {
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

addedInput schema / properties / aoi_geojson / default
```
Added value: +null
```

removedInput schema / properties / aoi_geojson / description

Removed value: -"Area of Interest as GeoJSON geometry for clipping (will use smallest bbox between this and bbox parameter)"

removedInput schema / properties / aoi_geojson / type
```
Removed value: -"object"
```

addedInput schema / properties / bbox / anyOf

Added value: +[
+  {
+    "items": {
+      "type": "number"
+    },
+    "type": "array"
+  },
+  {
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

addedInput schema / properties / bbox / default
```
Added value: +null
```

removedInput schema / properties / bbox / description

Removed value: -"Bounding box [west, south, east, north] in WGS84"

removedInput schema / properties / bbox / items
```
Removed value: -{
-  "type": "number"
-}
```
removedInput schema / properties / bbox / maxItems
```
Removed value: -4
```
removedInput schema / properties / bbox / minItems
```
Removed value: -4
```
removedInput schema / properties / bbox / type
```
Removed value: -"array"
```

addedInput schema / properties / catalog_url / anyOf

Added value: +[
+  {
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

addedInput schema / properties / catalog_url / default
```
Added value: +null
```

removedInput schema / properties / catalog_url / description

Removed value: -"STAC catalog URL (optional, defaults to Microsoft Planetary Computer)"

removedInput schema / properties / catalog_url / type
```
Removed value: -"string"
```

addedInput schema / properties / collections / anyOf

Added value: +[
+  {
+    "items": {
+      "type": "string"
+    },
+    "type": "array"
+  },
+  {
+    "type": "string"
+  }
+]

removedInput schema / properties / collections / description

Removed value: -"List of collection IDs to search within"

removedInput schema / properties / collections / items
```
Removed value: -{
-  "type": "string"
-}
```
removedInput schema / properties / collections / type
```
Removed value: -"array"
```

addedInput schema / properties / datetime / anyOf

Added value: +[
+  {
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

addedInput schema / properties / datetime / default
```
Added value: +null
```

removedInput schema / properties / datetime / description

Removed value: -"Date/time filter (ISO 8601 format, e.g., '2023-01-01/2023-12-31')"

removedInput schema / properties / datetime / type
```
Removed value: -"string"
```

addedInput schema / properties / force_metadata_only

Added value: +{
+  "anyOf": [
+    {
+      "type": "boolean"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": false
+}

addedInput schema / properties / limit / anyOf

Added value: +[
+  {
+    "type": "integer"
+  },
+  {
+    "type": "null"
+  }
+]

changedInput schema / properties / limit / default
```
Previous value: -100New value: +10
```

removedInput schema / properties / limit / description

Removed value: -"Maximum number of items to analyze for size estimation"

removedInput schema / properties / limit / maximum
```
Removed value: -500
```
removedInput schema / properties / limit / minimum
```
Removed value: -1
```
removedInput schema / properties / limit / type
```
Removed value: -"integer"
```

addedInput schema / properties / output_format

Added value: +{
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": "text"
+}

addedInput schema / properties / query / anyOf

Added value: +[
+  {
+    "additionalProperties": true,
+    "type": "object"
+  },
+  {
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

addedInput schema / properties / query / default
```
Added value: +null
```

removedInput schema / properties / query / description

Removed value: -"Additional query parameters for filtering items"

removedInput schema / properties / query / type
```
Removed value: -"object"
```
addedInput schema / required
```
Added value: +[
+  "collections"
+]
```

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "result": {
+      "items": {
+        "additionalProperties": true,
+        "type": "object"
+      },
+      "type": "array"
+    }
+  },
+  "required": [
+    "result"
+  ],
+  "type": "object",
+  "x-fastmcp-wrap-result": true
+}

First observedSep 21, 2025

TDQS

C2.6/5.0

Behavior2/5

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

With no annotations, the description must fully disclose behavioral traits. It only states 'estimate' without saying whether this is a read-only operation, whether it makes network requests, how the estimate is computed, or if it has side effects. This is insufficient for a tool that may execute queries.

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 with no fluff and front-loads the main verb. However, it is so brief that it sacrifices necessary detail, but for pure conciseness it earns a high score.

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?

Given 9 parameters, no annotations, and an output schema that is not provided in context, the one-sentence description is insufficient. It does not explain return values, output format behavior, or the impact of parameters on the estimate.

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

Parameters1/5

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

Schema description coverage is 0% and the description does not discuss any of the 9 parameters. The phrase 'STAC query' implies query parameters but gives no meaning to individual parameters like bbox, datetime, collections, limit, or output_format.

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

Purpose4/5

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

The description uses a specific verb 'estimate' and identifies the resource as 'data size for a STAC query'. This clearly distinguishes it from sibling search and retrieval tools, though the term 'data size' could be more explicit (e.g., number of items vs total bytes).

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 like search_items or get_aggregations. The description does not mention prerequisites, exclusions, or typical scenarios for use.

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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