searchPhoneNumbers

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

Annotations already mark readOnlyHint=true and openWorldHint=false. The description adds useful behavioral context beyond those: price and validity are flat per region, every result shows identical monthly_rental_usd and validity_days, and that amount is exactly what a purchase charges. No contradiction with 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?

Two sentences, front-loaded with the verb and resource, followed by a compact and important pricing caveat. No filler or repetition.

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?

For a simple read-only search tool with one required parameter and no output schema, the description adequately covers what the tool does, how region affects results, and the key pricing behavior. It doesn't enumerate return fields beyond the two mentioned, but the schema and annotations fulfill the essential calling contract.

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 100% and each parameter has a description, so baseline is 3. The description only reinforces that region determines the flat price; it does not add new parameter-level detail beyond the schema.

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?

States a specific verb ('Search'), a clear resource ('phone numbers available to buy in a region'), and scope. The phrase 'available to buy' distinguishes it from siblings like listPhoneNumbers (which likely lists owned numbers) and purchasePhoneNumber (which actually buys).

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 implies usage for browsing purchasable inventory, but it never explicitly states when to use this tool versus listPhoneNumbers or purchasePhoneNumber. No exclusions or alternative conditions are provided.

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