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

readOnlyHint=true already covers the safety profile, and the description usefully adds the delivery-status vocabulary and the 100-per-page cap. It does not cover pagination termination, ordering, or what happens with an invalid/unknown broadcast id.

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?

A single front-loaded sentence with no filler; the return content and page size are packed in efficiently. Slightly dense but nothing wasted.

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 no output schema, the description does the important work of telling the agent what a row contains (status per number), and pagination is covered by the schema. Only minor gaps remain around ordering and empty/error cases for a simple read tool.

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 coverage is 100%, so id, limit and start are already fully documented, including the next_start paging hint. The description's '100 per page' only corroborates the limit default; it adds no new parameter meaning beyond the schema.

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 ('List the recipients of a text broadcast'), plus what each row carries (delivery status per number). It implicitly separates itself from list_texts (broadcasts) and get_text (single broadcast), though it never names a sibling to make the distinction explicit.

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?

Usage is implied by the resource description — you call this to inspect who received a given broadcast — but there is no explicit when-to-use, when-not-to-use, or pointer to alternatives such as list_call_recipients or get_text.

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