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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so safety is covered. The description adds genuinely new behavioral context not derivable from the schema: the default result set is countries and groups (the `level` enum only lists department/municipality/district), and each record includes names, centre coordinates and area. That is meaningful disclosure beyond the structured fields.

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?

A single dense sentence that front-loads the verb and resource, then the default scope, then the drill-down option and returned fields. No filler, though the clause stacking makes it slightly hard to parse.

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?

With no output schema, the description usefully names what comes back (names, centre coordinates, area). It covers both the no-argument default and the filtered hierarchical case, which is the main thing an agent needs; pagination or result-size behavior is the only notable 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 description coverage is 67%: `name` and `within` are documented in the schema, while `level` carries only an enum with no description. The description partially compensates by explaining the hierarchy (departments/municipalities/districts nested under one country or department), clarifying the level/within interplay, but it adds little beyond the schema's own wording for name and within.

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 ("Lists place codes") and spells out both operating modes: the default countries/groups listing and the hierarchical drill-down by level within a country or department. It does not explicitly name the sibling search_places or contrast list-style enumeration with search, so it stops short of full sibling differentiation.

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?

Usage is implied through the default-vs-filtered framing ("by default, or the departments... of one country or department"), which tells the agent roughly when to supply `within`/`level`. However, it never states when to prefer this over search_places, nor any exclusions or prerequisites.

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