list_regions

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, and the description's GET endpoint is consistent with that. However, the description adds no behavioral context beyond the endpoint—no auth requirements, rate-limit notes, or response behavior details.

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 two short lines with no filler: a resource statement and the endpoint. It is appropriately minimal and front-loaded, though it borders on terse.

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 zero-parameter read-only tool, the description combined with annotations and the output schema is sufficient for safe invocation. The only notable gap is the lack of relationship to list_watchproviders_regions, but that does not affect calling this endpoint.

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 has zero parameters, so there is nothing for the description to document; schema coverage is effectively complete. The baseline of 4 applies because no parameter clarification is needed.

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 clearly names the resource ('Regions supported by TMDB') and provides the HTTP endpoint, so the agent can infer this is a read-only list operation. It does not explicitly say 'list' and does not differentiate itself from the similarly named sibling list_watchproviders_regions.

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?

There is no when-to-use guidance, exclusions, or mention of alternative tools. The agent is left to infer from the tool name and endpoint that this is the general regions endpoint, which could be confused with list_watchproviders_regions.

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