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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered; the description adds substantial context beyond that: case-insensitive matching, newest-first ordering, a 100-per-page cap, and the page/page.next continuation protocol with 0 marking the last page. That is exactly the behavioral detail an agent needs to page correctly.

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?

Four short sentences, front-loaded with purpose, then matching semantics, then the sibling alternative, then pagination mechanics. Every sentence carries information the agent needs; no filler.

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 two-parameter, zero-required list tool with an output schema present, the description covers everything the agent must decide: when to use it, matching semantics, ordering, page size, and how to continue paging. Return-value explanation is not needed given the output schema, and the pagination fields are still referenced usefully.

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 the baseline is 3; the description exceeds that by explaining the pagination contract ('Set page to the returned page.next to continue', 'A next value of 0 marks the last page'), which the schema alone does not convey. It adds no extra detail on the query parameter beyond the schema's own 'partial name or email, up to 200 characters'.

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 guests') plus the narrowing scope ('optional partial name or email matching'), and explicitly names the sibling it is not (guests.search for full-text matching). An agent can distinguish it from guests.search without opening either schema.

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?

Explicitly routes the agent: use guests.search for full-text matching, implying this tool is for plain partial name/email lookup. The 'Omit to list all guests' behavior is conveyed via the title/schema, so the choice between listing-all and searching is inferable without ambiguity.

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