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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safe-read nature is known. The description adds useful behavioral context by explaining that validation checks both geocoding and zone membership, and that a phone number is needed when the address is approximate.

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 tight sentences that front-load the core validation check and the pickup/dropoff distinction. The trailing API endpoint reference is minor but not wasteful, and no sentence is bloated.

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 read-only validation tool with full parameter documentation and no output schema, the description covers what is being validated and the key phone condition. It does not explain the return shape or failure behavior, which leaves a small gap given there is no output schema.

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 all parameters are already documented, including the type enum, phone requirement, and coordinates object. The description restates the pickup/dropoff distinction and phone condition but does not add meaningful syntax or format guidance 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?

The description states a specific verb ('Check') and resource ('address'), and clarifies that validation covers both geocoding and Stuart zone inclusion for pickup or dropoff. It is clear what the tool does, but it does not explicitly differentiate itself from the related zone-coverage sibling tool.

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 implies usage before job creation by framing validation around pickup and dropoff addresses, and notes the phone requirement for approximate addresses. However, it gives no explicit guidance on when to use this versus stuart_get_zone_coverage or other siblings, and no when-not-to-use cases.

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