qgis-dev-probe-mcp

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set_widget

Set a QGIS widget's value for text, number, boolean, or combo fields; rejects invisible, disabled, or read-only widgets to avoid invalid UI changes.

Instructions

Set a widget value (text, number, bool, combo index/text, ...). Refuses invisible/disabled/read-only widgets.

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": {
      "window": "<window>",
      "object_name": "<object_name>",
      "value": "<value>"
    },
    "name": "set_widget"
  }
}

Input Schema

Name	Required	Description	Default
`index`	No
`value`	Yes
`window`	Yes
`object_name`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Oct 25, 2026

TDQS

C2.9/5.0

Behavior3/5

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

With no annotations, the description carries the full behavioral burden. It usefully discloses refusal conditions for invisible, disabled, and read-only widgets, but it omits mutation side effects, return behavior, and error handling beyond refusal.

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 compact and front-loaded, with the core action stated first and the refusal constraint second. The trailing ellipsis in the value list is slightly vague but does not bloat the description.

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 mutation tool with no annotations, no output schema, and 0% schema description coverage, the description is incomplete. It should clarify how window/object_name/index identify the target and what happens on success or failure.

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 for four undocumented parameters. It hints at value types but does not explain 'window', 'object_name', or 'index', leaving most parameter semantics unclear.

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 and resource: 'Set a widget value', and lists accepted value categories (text, number, bool, combo index/text). It is clearly different from read-oriented siblings like read_log or dump_widgets, though it does not explicitly contrast with click_widget or trigger_action.

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?

The description gives a behavioral constraint ('Refuses invisible/disabled/read-only widgets') but does not say when to choose this tool over alternatives such as click_widget or trigger_action. There is no explicit when-to-use or prerequisite guidance.

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