QGIS MCP Server

Set Setting

set_setting

Destructive

Writes a QGIS setting using a key and value; use carefully because incorrect settings can change QGIS behavior.

Instructions

Write a QGIS setting. Use with care - incorrect settings can affect QGIS behavior.

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": {
      "key": "<key>",
      "value": "<value>"
    },
    "name": "set_setting"
  }
}

Input Schema

Name	Required	Description	Default
`key`	Yes
`value`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Nov 13, 2026

TDQS

C2.7/5.0

Behavior3/5

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

The annotation destructiveHint already signals that this tool can be destructive, and the description reinforces this by noting that incorrect settings can affect QGIS behavior. This adds a consequence dimension, but it does not disclose other behavioral traits such as persistence, whether a restart is required, whether the setting is validated, or if it overrides existing values. The description adds some value beyond the annotation but not rich context.

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 extremely concise, with two short sentences that front-load the core purpose ('Write a QGIS setting') and follow with a brief warning. Every word earns its place, but the brevity comes at the cost of missing essential parameter and usage details. It is efficient but under-specified.

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?

For a tool with two simple string parameters and no output schema, the description is still incomplete. It lacks any mention of parameter semantics, valid settings, examples, or what the write operation returns (if anything). The warning about affecting QGIS behavior is helpful, but the overall context is insufficient for an agent to invoke the tool correctly without external knowledge of QGIS settings.

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 explain what 'key' and 'value' mean or how they interact. The tool name and description imply a key-value pair, but there is no elucidation of valid keys, value formats, or examples. The description entirely fails to compensate for the schema's lack of parameter documentation.

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 clearly states 'Write a QGIS setting' with a specific verb and resource, distinguishing it from the sibling get_setting (read). However, it does not differentiate from set_project_variable or other setting-related tools, and the exact scope ('QGIS setting') remains somewhat generic without explaining whether it applies to global application settings or project-specific ones.

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 explicit guidance is provided on when to use this tool versus alternatives. The only added context is a cautionary warning ('Use with care'), which implies cautious use but does not state prerequisites, exclusions, or suggest alternatives like get_setting for reading. The description fails to help the agent decide between this tool and its siblings.

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

Deploy Server