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

Annotations already provide a strong behavioral profile: readOnlyHint=true, idempotentHint=true, destructiveHint=false. The description adds no additional behavioral context beyond saying 'Check', which is consistent with the annotations. It doesn't disclose potential quirks like whether the response is cached or live, but the annotation coverage lowers the burden.

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, front-loaded sentence with zero wasted words. It states the verb, the target resource, and the parameter in one pass, making it easy to scan and understand.

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 low-complexity tool with one parameter, strong annotations, and an output schema, the description covers the essential selection and invocation context. It doesn't mention how to obtain a valid call_id or enumerate possible statuses, but those are secondary given the output schema and simple purpose.

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% and the schema already explains call_id as 'The call ID to check'. The description's 'by its ID' adds no quantitative or formatting detail beyond the schema, so the baseline score of 3 is appropriate.

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 states a specific verb ('Check'), a clear resource ('status of a call'), and the key discriminator ('by its ID'). This differentiates the tool from siblings like list_recent_calls, get_call_recording, and get_phone_system_status without requiring the agent to infer intent.

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 phrase 'by its ID' provides clear context for when to use this tool: when the agent has a specific call_id and needs that call's status. It doesn't explicitly name alternative tools or exclusions, but for a simple single-resource lookup the usage context is reasonably clear.

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