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

Annotations already declare destructive=true, idempotent=false, openWorld=true, and the description adds real context beyond them: paid preparation only cancels dialing with no refund, and dispatched calls require reading later status because charges may still settle. The hedging verb 'Ask for this call to stop' usefully signals the stop is not necessarily immediate.

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?

Three compact sentences, front-loaded with the core action before the two conditional caveats. No filler, though the paid-preparation and dispatched-call sentences are dense enough to merit a second read.

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?

An output schema exists, so return values need not be explained. The description still covers the async nature of the stop, the refund exception, and the confirmation step, leaving little an agent would need before invoking it.

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 100%, with both callId and taskId fully documented (patterns, sources like prepare_task/list_tasks). The description adds no parameter-level detail, so the baseline of 3 applies.

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?

States a specific verb and resource: stop a call, scoped to the owner's intent. It is clearly distinguishable from sibling mutations like retry_call or approve_call by the 'stop' action, though it never names an alternative for comparison.

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?

Gives a triggering condition ('when the owner wants it stopped') plus two situational branches: paid business preparation and dispatched calls. It lacks explicit when-not-to-use guidance or named alternatives (e.g. close_task vs retry_call), which keeps it short of a 5.

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