qgis-dev-probe-mcp

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run_algorithm

Execute a QGIS Processing algorithm synchronously and retrieve its results and log; the QGIS UI is blocked until completion.

Instructions

Run a Processing algorithm synchronously. QGIS UI is blocked meanwhile. Returns results and the log.

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": {
      "algorithm_id": "<algorithm_id>",
      "parameters": "<parameters>"
    },
    "name": "run_algorithm"
  }
}

Input Schema

Name	Required	Description	Default
`timeout_s`	No
`parameters`	Yes
`algorithm_id`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Oct 25, 2026

TDQS

B3.2/5.0

Behavior3/5

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

With no annotations, the description carries the full burden. It usefully discloses that execution is synchronous and blocks the UI, and that results plus a log are returned, but it says nothing about timeout behavior, error handling, or whether a failed run leaves partial state — gaps that matter for a 600s default timeout operation.

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?

Three short sentences, front-loaded with the action and mode, with no filler. It is tight, though the brevity contributes to the semantic gaps noted elsewhere.

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

Completeness3/5

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

It covers return values adequately ('results and the log') so an output schema isn't required, but for a tool with a nested free-form argument and no annotations, the absence of parameter format guidance and timeout/failure semantics leaves the definition short of complete.

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% and the description explains none of the three parameters. The critical details — the expected format of algorithm_id (e.g. provider:name) and the shape of the free-form nested 'parameters' object — are undocumented in both places, and timeout_s is never mentioned.

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?

States a specific verb and resource ('Run a Processing algorithm') plus the execution mode ('synchronously'), which is more than a name restatement. It does not explicitly contrast with siblings like run_recipe or execute_code, so sibling differentiation is left to inference.

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

Usage Guidelines3/5

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

The blocking warning ('QGIS UI is blocked meanwhile') implies this should be used deliberately, but there is no explicit when-to-use / when-not-to-use guidance and no pointer to run_recipe or get_algorithm_params as the discovery path for algorithm_id.

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