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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered. The description adds real behavioral context beyond that: the default vs detail return shapes and the important constraint that it "Returns keys and coverage only, never figures." That negative guarantee is exactly the kind of info an agent needs to avoid misusing the result.

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?

Two tight sentences with the core behavior front-loaded (what it catalogs), followed by the mode behavior and the return constraint. Little waste, though the opening phrase is slightly opaque.

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 an annotated read-only listing tool with no output schema, the description adequately explains what is returned and in which mode. The gaps are the undocumented filtering parameters (season, entity_kind, limit), which an agent would need to filter the catalog meaningfully.

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 0% across 5 parameters, so the description carries the full burden. It documents only two of them (search, detail) and their effect on output; limit, season, and entity_kind are left entirely unexplained by both schema and description.

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 conveys that this surfaces the metric catalog ("What Muffed can answer on") and describes two output modes, default family summaries vs individual metric keys. However it never uses a clean verb+resource framing and relies on the undefined term "Muffed," so the purpose is inferable rather than stated crisply.

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 explains mode selection (default summary vs search/detail:true for individual keys), which is helpful conditional guidance. But it names no alternatives among siblings like search_metrics or get_metric_definition and gives no explicit when-to-use/when-not-to-use, leaving routing to inference.

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