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

With no annotations, the description carries full responsibility for disclosing behavior. It clearly explains the dual modes: returning the full catalogue vs. returning available years for a specific metric. It also discloses that coverage differs per metric with specific examples, making behavior predictable.

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 sentences long, front-loaded with the core purpose, and packs essential usage and behavioral details without redundancy. Every clause 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?

The tool has no output schema and only two optional parameters. The description covers what the catalogue contains, how to use parameters to get different results, and the temporal coverage nuances. This is sufficient for an agent to understand what to expect and how to interact.

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?

Although schema coverage is 100%, the description adds significant meaning beyond the schema. It explains that variableCode changes the response from a catalogue to a list of years, and that group filters by theme. This transforms the parameter from a simple filter to a mode switch.

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 identifies the tool as a catalogue of all Suomiatlas metrics and lists concrete examples (population, income, education, etc.). It also names its intended consumers (rank_areas, get_place_stats), distinguishing it from sibling tools.

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 explicitly instructs when to call the tool ('Call this to find the right variableCode for rank_areas or get_place_stats') and explains the alternative behavior when variableCode is passed. This gives clear guidance for usage versus alternatives.

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