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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, covering safety. The description adds 'up to optional limit,' which implies pagination/limiting behavior, but does not disclose additional traits like ordering or default behavior beyond the limit. Since output schema exists, return fields are already documented, so the incremental value is modest.

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 a single, front-loaded sentence that states the action, resource, scope, limit behavior, and return fields without redundancy. Every element earns its place.

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?

Given the simple list operation, a single optional parameter, and comprehensive annotations plus an output schema, the description fully covers the tool's behavior. It explains what is listed and the limit constraint; no further details are necessary for a tool of this complexity.

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 coverage is 0%, so the description must clarify the single 'limit' parameter. The phrase 'up to optional limit' explicitly indicates that limit caps the number of results and is optional. This adds meaningful semantics that the input schema lacks.

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 uses the specific verb 'List' with the resource 'fictional locations' scoped to 'Studio Ghibli films'. It also names the return fields (name, climate, terrain, surface water, films) and notes the optional limit, clearly distinguishing it from the sibling 'location' tool (singular) by implying a collection return.

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 implies its usage—when you want to list locations—but provides no explicit when-to-use vs alternatives, no exclusions, and no mention of the singular 'location' tool for fetching a single location. It lacks the explicit guidance seen in high-scoring examples.

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