Skip to main content
Glama
Sign In
QGIS MCP

QGIS MCP

by lefcgis
OverviewSchemaSourceRelated ServersDiscussionsAdmin
Python
Local

Set Layer CRS

set_layer_crs

Assign a coordinate reference system to a QGIS layer to correctly interpret its existing coordinates without reprojecting the data.

Instructions

Set the CRS of a layer (e.g. 'EPSG:4326'). This does NOT reproject data — it only changes how the layer's coordinates are interpreted.

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": {
      "layer_id": "<layer_id>",
      "crs": "<crs>"
    },
    "name": "set_layer_crs"
  }
}

Input Schema

NameRequiredDescriptionDefault
crsYes
layer_idYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.5.0

TDQS

A4.1/5.0
Behavior4/5

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

With no annotations, the description carries full burden. It reveals the key behavioral trait: no data reprojection, only reinterpretation. However, it does not mention reversibility, impact on rendering, or required permissions. Still, the most critical behavior is disclosed.

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 sentences, front-loaded with action, second adds vital nuance. Zero wasted words.

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

Completeness4/5

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

For a simple setter with 2 required params and no output schema, the description covers the core function and crucial caveat. Lacks error behavior or parameter format details, but sufficient for basic usage.

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

Parameters2/5

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

Schema description coverage is 0%, so the description must compensate. It provides one example for 'crs' but nothing for 'layer_id', and does not explain format or source for either parameter beyond name hints.

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 verb ('Set') and the resource ('CRS of a layer'), with an example format ('EPSG:4326'). It explicitly distinguishes from reprojection by stating 'does NOT reproject data', which differentiates it from sibling tools like transform_coordinates.

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 when to use (to assign CRS metadata) and when not (for reprojection), but lacks explicit alternatives or context like 'use transform_coordinates to actually reproject data.' The negative statement is helpful but not fully prescriptive.

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

Deploy Server

Other Tools