Spam Check

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds the useful constraint of 'one North American phone number' but does not disclose additional behavioral details such as response shape, data sources, or rate limits.

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, front-loaded sentence captures the tool's purpose with no filler. Every word earns its place, and the key scope qualifiers ('one', 'North American') are included without redundancy.

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, single-parameter, read-only tool with an output schema and full schema coverage, this description is complete enough. It tells the agent what the tool does and its geographic/single-number scope, while the annotations and schema cover safety and parameter details.

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?

The schema already documents the only parameter with 100% coverage, so the description adds little beyond reinforcing that it accepts one phone number. 'North American' aligns with the schema's US/Canada note but does not meaningfully extend the schema's meaning.

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 providing spam/scam/robocall reputation for a single phone number. The 'one North American phone number' qualifier distinguishes it from bulk-oriented siblings, though it does not name them explicitly or use an explicit verb like 'checks'.

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 by the domain terms 'spam/scam/robocall' and the single-number scope, so an agent can infer when to use it. However, the description offers no explicit when/when-not guidance or mention of alternatives such as vri_bulk_lookup or vri_sms_deliverability.

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