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

With annotations already declaring readOnlyHint=true and idempotentHint=true, the description adds valuable behavioral context: the list is sorted by collection-wide frequency, frequency is computed from articles + publications + references, and the Nigeria edge case is explained. These details go beyond the structured annotations and help the agent predict output behavior. It does not describe the return format, but that is a minor gap.

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 three sentences: the first states the main purpose, the second explains the tricky filter semantics, and the third gives a concrete example. Every sentence earns its place, and key information is front-loaded. No fluff.

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 complexity of the country filter, the description covers essential behavioral nuances and the frequency source, making it sufficient for a read-only list tool with pagination parameters documented in the schema. The only gap is the lack of explicit return field specification, but since no output schema exists and the tool is straightforward, this is not a critical omission.

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 67% (limit and country have descriptions; offset does not). The description significantly enriches the 'country' parameter by explaining that it selects mentioned-in entries and can include foreign/cross-border locations, plus the Nigeria caveat. This is more than the schema provides. Limit/offset are standard pagination parameters and need no further explanation.

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 exactly what the tool does: lists lieux from the IWAC index, sorted by frequency. It specifies the resource ('lieux' from the IWAC index) and the ordering, distinguishing it from sibling list tools like list_persons and list_subjects. The country filter semantics further clarify the tool's scope.

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 clear context on how to use the country filter, explaining the 'mentioned-in' versus 'located-in' distinction, which guides correct tool invocation. It also provides a concrete Nigeria example and the reason for the empty result. However, it does not explicitly name alternative tools (e.g., get_place_distribution) or state when not to use this tool, so it falls short of a 5.

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