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

The annotations already indicate read-only, idempotent, and non-destructive behavior. The description adds meaningful context beyond that: 'Free to call, no credits consumed' and the follow-up action of connecting to a URL or sending the X-Tool-Groups header. This gives the agent useful operational behavior not present in 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 with the core purpose and contains several valuable details: domain/tool counts, usage instructions, the loading URL/header, cost implications, and the optional query. The content is dense but useful; minor redundancy exists because the query parameter is already fully documented in the schema.

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?

Since there is no output schema, the description compensates by stating what the tool returns ('domain count and tool count'). It also covers the no-cost behavior, the optional filter, and the recommended next step for loading groups. The description is complete for a simple metadata-discovery tool with one optional parameter.

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 input schema fully documents the single optional query parameter, including that it is a case-insensitive substring filter. The description only repeats 'Optional query filters group names' without adding new semantic detail, so the baseline score of 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?

The description states a specific verb and resource: 'List every tool group ... with its domain count and tool count.' It clearly identifies what the tool does and what it returns, but it does not explicitly differentiate the tool from the similarly meta sibling search_available_datasets.

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 gives explicit usage guidance: 'Use this to discover which groups exist, then connect to ... to load ONLY those groups.' It also explains the benefit of filtering, which helps an agent know when to rely on this tool. It lacks explicit 'when not to use' statements or named alternatives.

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