Stop an active browser automation task that is still running. Use this to interrupt a task when you need to halt execution without waiting for completion.
Cancel a working task (Tasks extension fallback).
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes |
Changes observed during successful MCP inspections.
v0.2.3Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already declare destructiveHint=true, covering the destructive nature. The description adds the constraint that it applies to a 'working task', suggesting it may only affect in-progress tasks, which is useful but not elaborated. It does not contradict the annotations and provides minimal extra behavioral context beyond what is already structured.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, compact sentence with no wasted words. It is front-loaded with the primary action, though the parenthetical '(Tasks extension fallback)' is slightly cryptic and could be more transparent. Overall it is concise and structurally sound.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple one-parameter tool with destructiveHint annotation, the description still leaves significant gaps: the parameter is undocumented, there is no mention of what happens to the task after cancellation (e.g., status change, irreversibility), and no behavior for edge cases (e.g., task not found or already completed). The description does not fully enable correct invocation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
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 the 'id' parameter at all. The tool has one required parameter, but neither the schema nor the description provides any meaning (e.g., what id refers to, how to obtain it). The description must compensate for the low schema coverage but fails to do so.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description 'Cancel a working task' states a specific verb and resource, clearly distinguishing it from sibling tools like get_task, list_tasks, and wait_task which read or monitor tasks. The parenthetical '(Tasks extension fallback)' adds useful context about its role. This is specific and unambiguous.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description offers no explicit guidance on when to use this tool versus alternatives. It implies it is for tasks that are 'working', but there is no mention of when canceling is appropriate (e.g., task stuck, no longer needed) or when to prefer waiting or checking status instead. No exclusions or alternative pointers are provided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.