Mobile Automator MCP Server

Overview Schema Source Related Servers Discussions Admin

Cancel Task

cancel_task

DestructiveIdempotent

Abort a running task by sending SIGTERM to its child processes, executing cleanup callbacks, and marking it as cancelled. Idempotent operation.

Instructions

Aborts a running task: sends SIGTERM to children, runs registered cleanups in reverse order, marks the task cancelled. Idempotent and never throws.

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": {
      "taskId": "<taskId>"
    },
    "name": "cancel_task"
  }
}

Input Schema

Name	Required	Description	Default
`reason`	No
`taskId`	Yes

Output Schema

Name	Required	Description	Default
`taskId`	Yes
`notFound`	No
`cancelled`	Yes
`finalStatus`	No
`cancelReason`	No
`previousStatus`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jun 28, 2026

TDQS

A3.9/5.0

Behavior4/5

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

The description adds behavioral details (SIGTERM, cleanup order, never throws) beyond annotations that already indicate destructiveness and idempotency. No contradiction found.

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?

The description is two sentences, front-loaded with the core action, and every word adds value. No redundancy.

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?

Given the presence of an output schema and annotations, the description covers purpose, behavior, and safety. However, it misses prerequisites like the task must be running.

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?

With 0% schema description coverage, the description should explain parameters. It does not mention the 'reason' parameter and only implicitly references taskId. This forces the agent to infer parameter meaning from context.

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 tool aborts a running task with specific actions (SIGTERM, cleanups). It distinguishes itself from sibling tools like list_tasks or poll_task_status by focusing on cancellation.

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 cancel a running task) but does not explicitly mention when not to use or provide alternatives. It states idempotent and never-throws, which aids usage decisions.

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