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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds behavioral context by specifying the maximum number of matches (10), the fields returned (id, name, parent province/city), and the purpose of resolving place names. It doesn't mention edge cases like no matches or error handling, but the added context is valuable and doesn't contradict annotations.

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 concise and well-structured. It front-loads the core function, then provides output details, and finally gives usage guidance with examples. Every sentence earns its place, and there is no redundant information. The length is appropriate for the tool's complexity.

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 a read-only lookup tool. It covers the purpose, output, and usage context. The output schema is absent, but the description explicitly states what the tool returns (up to 10 matches with id, name, parent province/city), which compensates. It doesn't mention pagination or error cases, but for a simple autocomplete tool, this is sufficient. The annotations cover safety, so the description doesn't need to repeat that.

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 both parameters ('query' and 'provinces'). The description adds context about the 'query' parameter by giving examples of free-text place names, but it doesn't add significant meaning beyond the schema. The 'provinces' parameter is not elaborated in the description, but the schema's description is sufficient. Baseline 3 is appropriate.

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: looking up Spanish property areas by free-text name, with a specific verb ('Look up'), a resource ('Spanish property areas'), and a defined output (up to 10 matches with id, name, parent province/city). It distinguishes itself from siblings by explicitly mentioning its role in resolving place names before calling search_properties, which is a clear differentiator.

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 explicitly states when to use this tool: 'Use this to resolve place names before calling search_properties'. It also provides concrete examples of common spelling variations ('Nueva Andalucia' vs 'Nueva Andalucía') and 'Marbella old town', which helps an agent understand the intended use case. It doesn't explicitly mention when not to use it, but the context and examples make the usage clear.

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