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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the read-only nature is covered. The description goes well beyond annotations by disclosing the caveats field, that 48% of departures state no destination, that totals are a floor, and that a 2015/2016 definitional break exists. This is exactly the kind of behavioral nuance an agent needs.

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 dense but well-structured: it front-loads the data source, then the return fields, then critical caveats, then usage instructions. It could be slightly trimmed, but the statistical context and caveats are valuable enough to justify the length.

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 description is complete for an agent to call this tool correctly: it identifies the data source, year range, return dimensions, critical caveats, and licensing requirements. With a full input schema, output schema, and read-only annotations, no essential operational context is missing.

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 100%, so the schema already documents all three parameters. The description's 'Pass year, destination or top' adds minimal extra meaning beyond what the schema provides, but it confirms the expected call pattern without conflicting with it.

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 states the tool's function: returning departures, arrivals, net migration, and destination share from official German emigration statistics. It identifies the specific data source (Destatis statistic 12711-0008) and scopes it by destination and year, making it unambiguously distinct from the broad set of migration-related siblings.

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 concrete usage context: pass year, destination, or top, and explicitly warns not to trend across 2015/2016 due to a definitional break. It also frames the tool as revealing preference rather than suitability. However, it does not name alternative tools or explicitly state when to prefer one sibling over another.

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