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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds value beyond that by disclosing the return shape ('{ users[], next }'), which matters because there is no output schema, and by flagging the pagination model via the 'next' token.

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 tight sentences, each earning its place: purpose, capabilities, endpoint, and return shape, all front-loaded with 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 read-only listing tool with nine fully documented optional parameters, the definition covers purpose, endpoint, filtering, and the paginated return contract. Lack of explicit guidance on result size limits or how filters combine is a minor remaining gap rather than a blocking one.

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 every parameter (limit, token, nickname, active_mode, metadata pair, etc.) is already self-documented. The description's filter list maps to those parameters but adds no syntax or pairing detail beyond what the schema provides — the baseline 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?

States a specific verb and resource ('List the users in the application') and enumerates the filter dimensions, so an agent can distinguish this list operation from the singular sendbird_get_user. It stops short of naming that sibling explicitly, so differentiation is implied rather than stated.

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 description lists what can be filtered (activity, nickname, ids, metadata), which implies when the tool is useful, but it never says when to prefer it over sendbird_get_user or how filtering interacts with paging. Usage is inferable rather than guided.

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