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

The annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the HTTP endpoint GET /contacts/groups, but does not disclose return format, pagination, or any other behavioral detail beyond the annotations.

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?

The description is front-loaded and brief, consisting of one useful sentence plus the endpoint. Every element earns its place, with no redundant or filler text.

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 simple, no-parameter list tool with annotations covering safety, the description is largely complete. It tells the agent that the result contains contact groups whose IDs can be used elsewhere, though it does not describe the exact response shape or pagination behavior.

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 has zero parameters, so there are no parameter semantics to explain. The schema is empty and no additional parameter guidance is needed, which matches the baseline of 4 for a no-parameter tool.

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?

The description gives a specific verb and resource: 'List the contact groups.' It also clarifies the relationship to the sibling bukku_list_contacts by explaining that group IDs are used to filter contacts, which distinguishes this tool from listing contacts directly.

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?

It provides a clear use case: retrieve contact groups so their IDs can be used to filter bukku_list_contacts. However, it does not state when not to use this tool or explicitly compare it with alternatives such as bukku_list_tags or bukku_list_contacts.

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