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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds useful non-annotation context: the result ordering (active first, then recently updated/created, with stable tie-breakers) and the volatility note 'Results can change between requests.' It does not mention auth requirements or rate limits, keeping it from a 5.

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 front-loaded with the tool's purpose and returned fields, then adds usage, ordering, pagination, and volatility notes. It is efficient overall, though the 'Defaults: limit 100, offset 0; maximum limit 100' sentence partially duplicates schema information, which slightly reduces the value density.

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?

With an output schema present, the description need not explain return values. It covers the practical needs for a paginated list tool: what is listed, why to use it, how results are ordered, how to paginate, and that results can shift between requests. Nothing essential for correct invocation is missing.

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%, so the schema already documents limit, offset, and include_inactive fully. The description repeats defaults and the maximum limit, and mirrors the schema's guidance to continue with meta.next_offset, adding little beyond the structured fields. Baseline 3 is appropriate when the schema does the heavy lifting.

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 and resource: 'List the iPhones and iPads paired to this account,' and enumerates the returned fields. It clearly distinguishes this tool from siblings like list_account_users and list_channels by scoping to paired devices.

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?

It explicitly says to use it to find device_id values for set_channel_devices, giving a concrete downstream consumer. It does not state when not to use it or name alternative list tools, so it falls short of a full when/when-not/alternatives treatment.

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