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watershed

Idempotent

Generates a basin raster (GeoTIFF) from a DEM and pour points, assigning each basin a 1-based ID in point order. Non-draining cells remain nodata; points are aligned to the DEM CRS.

Instructions

Watershed of each pour point: DEM + points in, basin raster out (GeoTIFF).

Basins get 1-based IDs following the pour-point feature order; cells not draining to any point stay nodata. Points are aligned to the DEM CRS automatically (decision recorded). Requires the [whitebox] extra.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "dem_path": "<dem_path>",
      "pour_points_path": "<pour_points_path>",
      "output_path": "<output_path>"
    },
    "name": "watershed"
  }
}

Input Schema

Name	Required	Description	Default
`dem_path`	Yes
`output_path`	Yes
`pour_points_path`	Yes

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.3.0Aug 29, 2026

TDQS

A4.7/5.0

Behavior5/5

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

Beyond annotations, the description discloses the 1-based ID ordering, nodata behavior for non-draining cells, automatic CRS alignment with a recorded decision, and the whitebox dependency. These are meaningful behavioral details an agent would not otherwise know.

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?

Three sentences, each earning its place: purpose, output semantics, and dependency/CRS behavior. The most important information is front-loaded in the first sentence.

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?

For a three-parameter raster-processing tool, this description covers purpose, output format, ID semantics, nodata behavior, CRS handling, and required extra. Nothing essential is missing for an agent to select and invoke it correctly.

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

Parameters4/5

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

The input schema has no parameter descriptions, so the description must compensate. It maps dem_path to DEM, pour_points_path to pour points, and output_path to the basin raster GeoTIFF, and adds CRS alignment context. This is sufficient for correct invocation, though explicit per-parameter naming is absent.

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 names a specific operation (watershed delineation), states the inputs (DEM, pour points), and the output (basin raster GeoTIFF). This clearly differentiates it from sibling tools like flow_accumulation or hillshade.

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

Usage Guidelines4/5

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

The description implies usage clearly: use when you need watersheds from a DEM and pour points. It does not explicitly name alternatives or exclusion cases, but the specialized input/output pattern gives enough context for an agent to select it.

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