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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so safety is covered; the description still adds the auth requirement ('Needs the user's Cotlet API key with access to this app'), which is genuinely useful behavioral context. No pagination or rate-limit detail is provided.

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, front-loaded with the purpose and return content before the dependency and auth notes. Slight redundancy between the title line and the 'Returns every group' sentence, but 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?

With no parameters, no output schema and read-only annotations, the description carries the right load: it summarizes the returned shape (ID plus member count), plus the dependency and auth needs. Only deeper return-format or pagination details are absent, which is minor here.

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?

The tool takes zero parameters, so the baseline is 4. The description adds no parameter guidance, but none is required, and it correctly explains that group_id values flow out of this response into other tools.

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 groups') and clarifies the payload returns every group with its ID and member count. It hints at the distinction from sibling list_group_members by clarifying groups hold 'the people you invite,' though it never names that sibling outright.

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 clear downstream context: 'Use group_id from each item in create_signup, list_group_members and add_group_member,' which tells the agent why this call matters. It stops short of an explicit when-not-to-use or direct alternative comparison.

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