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

Annotations already declare readOnlyHint/destructiveHint, so the bar is lower, but the description still adds real behavior: the default exclusion of deactivated clients, client ordering as Trainerize presents it, a 200-per-page limit with cursor continuation, and the Cotlet API key requirement with app access. No rate limits or error behavior mentioned, so not 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?

Five tight sentences, front-loaded with what the tool returns and the scope, then filtering, pagination and prerequisites. Nothing is padding, and the next_cursor/cursor mapping is a genuinely useful clarification rather than 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 list tool with no output schema and zero required params, the description covers scope, default filtering, ordering, paging and auth prerequisites. It hints at returned fields (client type, trainer, tags, last activity) but doesn't describe the response shape, which is the only notable gap.

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 tag, limit, cursor, search and the client_type enum with its default. The description largely restates these (tag grouping, name/email search, 200 per page, deactivated default), adding only the 'next_cursor back as cursor' clarification. Baseline 3 is correct.

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?

Opens with a specific verb ('Lists') and resource ('clients'), then names the scope ('clients you can see') and the ordering semantics. An agent can distinguish it from trainerize_get_client (single client) and from the other trainerize_list_* tools without opening the 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?

Gives concrete routing guidance: deactivated clients are excluded unless requested via client_type, use tag to get a group, use search for name/email. It never names a sibling alternative (e.g. get_client for one record), so it stops short of the explicit when-not/alternative framing of a 5.

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